MATTER
Matter is anything that has weight and can occupy space or volume. Matter can be pure (elements and compounds) or impure (mixtures). Mixtures can be homogenous (exist in one phase and it is uniform) or heterogeneous (exist in two or more phases and it is non-uniform).
A molecule is defined as the smallest uncharged particle of an element or a compound which moves about as a whole such that its components part do not detach during the motion. E.g a water molecule consists of two atoms of hydrogen and one atom of oxygen, a molecule of element can be monoatomic [Ar(argon), He(helium)]. Diatomic (H2, N2, Cl, O2), or polyatomic (O3, P4, S8)
STATES OF MATTER
STATES OF MATTER
Matter exist in five states. But the three major ones are the solid, liquid and gases.
1. Solid: the molecules that make up a solid are arranged in regular, repeating patterns. They are held firmly in place but can vibrate within a limited area.
2. Liquid: the molecules that make up a liquid flow easily around one another. They are kept from flying apart by attractive forces between them. Liquid assume the shape of their containers.
3. Gas: `The molecules that make up a gas fly in all directions at great speeds. They are so far apart that the attractive forces between them is insignificant .
4. Plasma: At the very high temperature of stars, atoms lose their electrons. The mixtures of electrons and nuclei that results is the plasma state of matter.
CHANGES IN MATTER
Physical and chemical changes
Chemical changes means change in chemical state or composition while physical change involve changes in the physical state.
3. PHYSICAL CHANGES
2. CHEMICAL CHANGES
JAMB QUESTION
1. These are basic particles from which matter could be made except . A. Atom B. Salt. C. Ion. D. Molecule
Answer
Recall from the notes that the basic particles that form matter are: Sub atomic particles → atoms → elements(or ions) → molecules → compounds → mixture → matter. Salt are generally made up of aggregate of ions. ANS: SALT
2. It is difficult to achieve an orderly arrangement of the molecules of a gas because they __. A. have no definite shape B. have little force of attraction between them. C. are too small in size D. can collide with one another in the container
Answer
It is difficult to achieve an orderly arrangement of the molecules of a gas because they have little force of attraction between them [B]
There are three major types of matter (Solid, Liquid and Gases). These three states can be differentiated based on the arrangement of their particles, which is as a result of forces of attraction between the molecules, space or volume occupied, degree of movement (kinetic energy). If the force of attraction is appreciable between the molecules, the molecules have an orderly arrangement ( as seen in solids). The gaseous molecules have great entropy (disorder) due to negligible forces of attraction that exist.
3. Which of the following properties is not peculiar to matter? A. Kinetic energy of particles increases from solid to gas B. Random motion of particles increases from gas to solid C. Orderliness of particles increases from gas to liquid. D. Random motion of particles increase from liquid to gas
Answer
Recall, the degree of disorderliness[Entropy] increase from solid to gas. Because the molecules gain more kinetic energy and move at random in gas than in liquid and solid
4. When a solid substance disappears completely as a gas on heating, the substance is said to have undergone A. evaporation B. distillation C. crystallization. D. sublimation
Answer
SUBLIMATION
The three states of matter can be change from one phase to the other. This is called Change of State. Evaporation involves the loss of vapour from the surface of a liquid ( it is a liquid-vapour transition). Distillation is a separating technique used to separate two miscible liquids mixtures at their different boiling points. Distillation is different from evaporation in that the liquid lost can be recovered through condensation. Crystallization is the separating technique used in recovering two soluble salts mixture. Sublimation is the change of state of some solid substances directly to the gaseous phase without passing through the liquid. ANS: D
5. solid begins to melt when? A. constituents particles acquire a greater kinetic energy. B. energy vibration of particles of the solid less than the intermolecular forces C. constituent particles acquire energy above the average kinetic energy D. energy of vibration of particles of the solid equals the intermolecular forces.
Answer
Note that the kinetic energy of particles can increase and the state of matter might not undergo changes. Solid particles can continue to vibrate, more and more in their mean position. But, there would be a change of state when the particles that make up matter acquire kinetic energy above the average kinetic energy of the particles. The energy involved in the change of state at a constant temperature is called Latent energy (Hidden energy). ANS: C
6. A difference between chemical and physical change is that in a chemical change A. oxygen consumed. B. heat is supplied C. a reversible process occurs D. a new substance is formed
Answer
Matter undergoes two changes which are physical and chemical changes. Physical changes are associated with physical properties in which no new substance are formed and are easily reversible while chemical changes involve transformation in which new substances are formed and are not easily reversible. ANS: D
7. Which of the following process is a physical reaction? A. Electrolysis B. Hydrolysis C. Allotropic change D. Neutralization E. Corrosion
Answer
Every forms of chemical reactions are chemical changes such as; Fermentation, rusting of iron ( a form of corrosion), neutralization, dissolution of metals in acids, decay of substances, burning of candle wax ( every form of burning), hydrolysis 9 splitting with water). Physical changes are; change of states, dissolution of salts in water, melting of candle wax, allotropic change (this involve same element existing in different forms at different conditions of temperature and pressure, but exhibiting same chemical properties). ANS: C
8. The addition of water to calcium oxide leads to? A. a physical change B. a chemical change C. the formation of a mixture D. an endothermic change
Answer
The addition of water to calcium oxide (quick lime) is called slaking of lime. This produces slaked lime (calcium hydroxide). It is an exothermic process. ANS: B
9. A small quantity of solid ammonium chloride ( NH4Cl) was heated gently in a test-tube, the solid gradually disappears to produce two gases. Later, a white cloudy deposit was observed on the cooler part of the test tube. The ammonium chloride is said to have undergone. A. distillation B. sublimation C. precipitation. D. evaporation E. decomposition
Answer
Ammonium chloride in this case undergoes thermal dissociation. It is a form of decomposition reaction. But the process of changing from solid directly to the gaseous state is known sublimation.
10. Which of the following substances is a mixture? A. Sulphur powder B. Bronze. C. Distilled water. D. Ethanol
Answer
Mixture is formed from the combination of two or more substances cannot be represented with a formula e.g Air, alloys, vulcanizer’s solution, urine, blood, flood and sea water e.t.c. Bronze is an alloy of copper and tin. ANS: B
11. In an attempt to remove sugar from a beaker containing a quantity of sand and sugar, 2M ammonium chloride solution was accidentally, added instead of water. Which of the following method could be used to remove the ammonium chloride from the mixture? A. Fractional distillation B. Crystallization c. Filtration followed by evaporation. D. Evaporation followed by sublimation E. Filtration followed by sublimation
Answer
Since the ammonium chloride is in solution (ammonium chloride and water), you have to filter it first to separate the insoluble sand, then evaporate the water and sublimate the ammonium chloride leaving sugar behind. ANS: D
12. The presence of an impurity in substance will cause the melting point to. A. be zero B. reduce. C. increase D. be stable
Answer
If it is pure, it melt at exact or narrow range of melting points but if it’s impure it decrease or melt at a wide range of temperature below the normal melting point. ANS: B
13. The dissolution of common salt in water is a physical change because. A. the salt can be obtain by crystallization B. the salt can be recovered by the evaporation of water C. heat is not generated during mixing. D. the solution will not boil at 1000c
Answer
To recover salt from its solution, it is evaporation to dryness. ANS: B
14. Which of the following is a physical change? A. The bubbling of chlorine into water B. The bubbling of chlorine into a jar containing hydrogen C. The dissolution of sodium chloride in water D. The passing of steam over heated iron
Answer
The dissolution of sodium chloride in water [C]
15. The filter in the cigarette reduce the nicotine by A. burning B. absorption C. evaporation D. absorption
Answer
Just like chromatography, the nicotine content is a solute carried by the smoke (mobile phase) and it is removed by filter (stationary phase) by absorption. ANS: D
16. Which of these require crystallization most? A. Drug making B. Cement making C. Paint making D. Perfume making
Answer
A. Drug making
17. Which of the following is an example of a mixture? A. Common salt B. Blood. C. Sand. D. Washing soda
Answer
Is blood.
18. Which of the following compounds and elements would sublime on exposure to the atmosphere? A. Ice B. Sulphur C. Phosphorous D. Iodine E. Potassium iodide
Answer
Examples of substance that will sublime on heating are; dry ice, iodine crystal, naphthaline, ammonium chloride, camphor. ANS: D
NOTE: dry ice is different from ice
19. A mixture of sand, ammonium chloride and sodium chloride is best separated by ? A. Sublimation followed by addition of water and filtration. B. Sublimation followed by addition of water and evaporation C. addition of water followed by filtration and sublimation. D. addition of water followed by crystallization and sublimation
Answer
Sublimation followed by addition of water and filtration
Sublimation helps to remove ammonium chloride. Dissolution allows the sodium chloride to dissolve which is then filtered leaving the sand as a residue. ANS: A
20. A pure solid usually melts? A. Over a wide range of temperature. B. Over a narrow range of temperature. C. at a lower temperature than the impure one. D. at the same temperature as the impure one
Answer
A pure solid usually melts over a narrow range of temperature
21. Which of the following methods can be used to obtain pure water from a mixture of sand, water and methanoic acid? A. neutralization with NaOH followed by filtration B. neutralization with NaOH followed by distillation C. fractional distillation D. filtration followed by distillation
Answer
Filtration removes sand as a residue. The mixture of two miscible liquids ( water and methanoic acid) can be separated by distillation.
22. A liquid begins to boil when? A. its vapour pressure is equal to the vapour pressure of it solid at room temperature B. molecules start escaping from its surface. C. its vapour pressure equals the atmosphere pressure D. its volume is slightly increased
Answer
its vapour pressure equals the atmosphere pressure
23. The movement of liquid molecules from the surface of the liquid to the gaseou s phase above it is known as? A. Brownian movement B. Condensation C. Evaporation D. Liquefaction
Answer
The movement of liquid molecules from the surface of the liquid to the gaseous phase above it is known as Evaporation
24. In the experiment, which of the following observations would suggest that a solid sample is a mixture? The. A. solid can be ground to a fine powder B. density of the solid is 2.25gdm-3 C. solid begins to melt at 573k but is not completely melted until 648k D. solid absorbs moisture from the atmosphere and turns into liquid E. solid melts at 300k
Answer
Option C shows that the solid melts at a wide range of temperature. Which means it is impure. Having a constant density, or exact melting point shows it is pure. ANS C
25. Which of the following substance is a mixture? A. granulated sugar. B. Sea-water C. Sodium chloride D. iron fillings
Answer
Sea water
26. The boiling point of water, ethanol, toluene and butan-2-ol are 375.0k, 351.3k, 383.6k and 372.5k respectively. Which liquid has the has the highest vapour pressure at 323.0k? A. water B. Toluene C. ethanol D. butan-2-ol E. None
Answer
The vapour pressure is the rate at which the molecules of liquid escape and collide with one another and with the walls of the container. Highly volatile liquids have high vapour pressure. A liquid with high boiling point have low vapour pressure. Ethanol has the lowest boiling point at the temperature indicated, it therefore has the highest vapour pressure. ANS: C
27. Which of the following properties is NOT peculiar to matter? A. Kinetic energy of particles increased from solid to gas B. random motion of particles increased from liquid to gas C. Orderliness of particles increases from gas to liquid D. Random motion of particles increases from gas to solid
Answer
Random motion of particles increases from gas to solid
28. A mixture of calcium chloride and calcium trioxocarbonate (IV) in water can be separated by A. evaporation B. sublimation C. distillation D. filtration
Answer
Calcium chloride is soluble in water while calcium trioxocarbonate (IV) is insoluble. The best method of seperation is filtration. ANS: D
29. A chemical reaction is always associated with A. an increase in the composition of one of the substance B. a change in the volume of the reactant. C. a change in the nature of the reactants. D. the formation of new substance
Answer
the formation of new substance
- A mixture of sugar and sulphur can be separated by. A. Dissolution in water, evaporation and filtration B. Filtration, evaporation and dissolution in water. C. in water, filtration and evaporation. D. Evaporation, dissolution in water and filtration
Answer
The first step is dissolution ( to form sugar solution), followed by filtration and then evaporation to dryness. ANS: C - Which of the following is a physical change? A. Freezing ice cream. B. Dissolving calcium in water. C. Burning kerosene. D. Exposing white phosphorus to air
Answer
Freezing ice cream - Which of the following processes NOT lead to a chemical change? A. Stirring iron in sulphur (IV) acid. . B. Stirring sodium carbonate in water. C. Stirring glucose in concentrated sulphur (IV) acid . D. Mixing sulphur (IV) acid with potassium carbonate . E. Titrating an acid against base
Answer
Reaction of iron with sulphur (IV) acid will liberate SO2. Stirring glucose in concentration. H2SO4 is called charring of sugar ( it produces sugar charcoal). Mixing sulphur (IV) acid with potassium carbonate liberates CO2. Acid against a base is a neutralization reaction. Option B shows dissolution of salt in water which is a physical change. ANS: B - Which of the following statements about volatile liquid is correct? A. High vapour pressure and low boiling point. B. Low vapour pressure and low boiling point. C. High vapour pressure and low boiling point . D. Low vapour pressure and high boiling point
Answer
High vapour pressure and low boiling point
Volatility deals with the rate at which the vapour escapes into the atmosphere. Ethanol (boiling point of 78⁰c ) is more volatile than water (boiling point of 100⁰c). This shows that, the higher the boiling point, the lower the vapour pressure and the lower the volatility. - The separation of a mixture of calcium trioxocarbonate (IV) is most easily carried out by using the differences in their. A. Physical state. B. Melting point. C. Rf. Values. D. Solubility. E. Boiling points
Answer
All salts of sodium, potassium and ammonium are water soluble. Calcium trioxocarbonate (IV) is insoluble. To seperate a mixture of the two salts, we use crystallization which the principle is based on their solubility. ANS: D - Which separation technique is routinely applied in the petroleum industry? A. Chromatography. B. Distillation. C. Evaporation. D. Fractional crystalization. E. Fractional distillation
Answer
The fraction of crude oil are seperated into their components by fractional distillation at their different boiling point. - A mixture of iodine and sulphur crystals can be separated by treatment with. A. Water to filter off sulphur. B. Carbon (IV) sulphide to filter off iodine. C. Ethanoic acid to filter off sulphur. D. Methanol to filter off iodine
Answer
The suitable solvent for sulphur is carbon (IV) sulphide. When sulphur dissolves, the solid iodine is filtered off. - A little quantity of trichloromethane (b.pt60⁰c) was added to a large quantity of ethanol (b.pt78⁰C). The most probable boiling point of the resultant mixture is from. A. 69⁰C-70⁰C. B. 70⁰c-74⁰c. C. 82⁰c-84⁰c. D. 60⁰c-78⁰c
Answer
Mixing trichloromethane with ethanol makes the mixture impure. Impurity always increases the boiling point of liquids as opposed to melting point of solid which is reduced. Impure liquid as a wide range of boiling point above the normal boiling point. Since they both boil normally at 60⁰c and 78⁰c and are mixed. The mixture will boil at a temperature higher than 78⁰c ANS: C - The chromatography separation of ink is based on the ability of the components to A. React with solvent. B. React with each other. C. Dissolve in each other in the column. D. Move at different speeds in the column
Answer
Chromatography is a seperating technique majorly used in seperating colours, ink and blood components. It has two phases, a stationary ( usually an absorbent) and a mobile phase(eluent). The solute to be seperated move at different speed and are collected at the surface (Absorption). The principle chromatography works on is the rate of migration of the solute over the absorbent. ANS: D - A mixture is different from a compound because. A. the properties of a compound are those of its individual constituents while those of a mixture differ from its constituents. B. a mixture is always homogeneous while a compound is not. C. the constituents of a compound are chemically bound together while those of a mixture are not. D. a mixture can be represented by a chemical formula while a compound cannot
Answer
A compound has a property entirely different from those of it constituent elements. A mixture can be homogeneous or heterogeneous while a compound is always homogeneous. The constituents of a compound are chemically bound while those of mixture are are physically mixed and can be seperated physically. A mixture cannot be represented with a chemical formula while a compound is represented with a chemical formula. ANS: C - The vapour pressure of a liquid depends on I. temperature. II. rate of condensation. III. cohesive forces holding the particle together
A. I only. B. I and II only. C. I and III only. D. II and III only
Answer
C ( temperature and cohesive forces holding the particle together)
The vapour pressure of a liquid is the pressure exerted by the escaping molecules of the liquid. The type of force (cohesive) between the molecules determine how easily it will evaporate. Weak forces evaporate easily and have high vapour pressure but strong forcesdo not allow easy evaporation and this confer low vapour pressure. - When naphthalene on heating changes from the solid state directly to the gaseous state it undergoes. A. evaporation. B. sublimation. C. decomposition. D. combustion. E. ionization
Answer
Sublimation takes place - CuSO4.5H2O can be obtained from an aqueous solution of copper (II) tetraoxosulphate (IV) by A. evaporation to dryness. B. using chromatography. C. Precipitation. D.
Answer
The water associated with CuSO4.5H2O is called water of crystalization which gives a blue colour and crystaline shape. The salt is obtained through the process of crystallization. ANS: D - A visible change is observed when a strip of iron is placed in an aqueous solution of
A. FeSO4. B. ZnSO4 C.CuSO4 D. MgSO4
ANS
Iron has the ability to displace copper from its solution. A visible color change occur. ANS: C - One of the following technique can be used to show the chlorophyll pigment is a mixture of chemical compounds and not a single coloured compound. A. crystallization B. hydrolysis C. sublimation D. filtration E. chromatography
Answer
Chromatography is used to analyze plant pigments. ANS: E - The most suitable method to use when separating an insoluble solid from a liquid is A. evaporation B. filtration C. magnetization D. sublimation E. distillation
Answer
Filtration - Sieving is a technique used to separate mixture containing solid particles of A. small sizes B. large sizes C. different sizes D. the same sizes
Answer
Different sizes - which of the following can be obtained by fractional distillation? A. nitogen from liquid air B. sodium chloride from sea water C. iodine from a solution of iodine in carbon tetrachloride D. sulhur from a solution of sulphur in carbon disulphide
Answer
During the liquefaction of air, the components of air are seperated using fractional distillation at their different boiling points. ANS: A - Which of the following are mixtures i. petroleum ii. Ruber lartex iiii. Vulcanizer’s solution iv. Carbon (ii) sulphide A. I, ii and iii B. I, ii and iv C. I and ii only D. I and iv
Answer
Petroleum, rubber latex and vulcanizer’s solution [A] - A difference between chemical and physical change is that in a chemical change A. oxygen is consumed B. heat is supplied C. the reversible process occurs D. a new substance is formed
Answer
Is D [ a new substance is formed] - A mixture of iron and sulphur can be separated by dissolving the mixture in? A. steam B. dilute hydrochloric acid C. dilute sodium hydroxide D. benzene
Answer
In order to seperate the mixture into their components. Benzene is best used. Benzene being non polar dissolves non polar sulphur. But the iron will dissolve with HCL. If HCL is used and it will lead to a chemical change. The use of benzene is a physical change - The property of calcium chloride which makes it useful as drying agent is that it is A. ionic B. deliquescent C. a strong electrolyte D. a normal salt
Answer
Deliquescent substances are substance which absorbs mosture from the atmosphere and turn to solution when exposed.so calcium chloride is a deliquescent substance which makes it a drying agent. - Which of the following element is diatomic? A. sodium B. oxygen C. iron D. neon
Answer
Oxygen [O2], because it’s made up of two atoms - Pure solvents are obtained by A. distillation B. condensation C. extraction D. evaporation
Answer
Distillation combines with evaporation or vaporization ( the heated molecules gain kinetic energy and vaporize) and condensation (using a condenser to collect the vapourized liquid) to obtain pure solvent. ANS: A - For iodine crystals to sublime on heating, the molecules must acquire energy that is? A. less than the forces of attraction in the solid B. equal to the forces of attraction in the solid C. necessary to melt the solid D. greater than the forces of attraction in both the solid and the liquid phases
Answer
greater than the forces of attraction in both the solid and the liquid phases - The fundamental differences between the three state of matter is the A. shape of the particles B. number of particles in each state C. shape of the container they occupy D. degree of movement of the particles
ANS
Degree of movement of the particles - Which of the following is physical change? A. burning kerosene B. freezing ice cream C. exposing white phosphorous D. dissolving calcium in water
Answer
freezing ice cream - A mixture of petrol and water can be separated through A. centrifugation B. distillation C. the use of separating funnel D. the use of filter paper
Answer
Petrol is non-polar and water is polar. To seperate two immiscible liquid we use seperating funnel - A substance is said to be impure if A. its melting point ranges is wide B. it dissolves
in water with difficult C. it has a low melting point b D. it is coloured
Answer
A. its melting point ranges is wide - The principle of column chromatography is based on the ability of the constituents to?
A. Move at different speeds in the column
B. Dissolve in each other in the column
C. React with the solvent in the column
D. React with each other in the column
Answer
A. Move at different speeds in the column - Chromatography is used to separate components of mixtures which differ in their rates of? A. diffusion B. migration C. reaction D. sedimentation
Solution
Check solution 38, migration is the answer (B) - Methanoic acid mixes with water in all proportions and has about the same boiling point as water which of the following methods would you adopt to obtain pure water from a mixture of sand, water and methanoic acid? A. fractional distillation B. filtration followed by distillation C. neutralization with sodium hydroxide followed by distillation D. esterification with ethanol followed by distillation E. neutralization with sodium hydroxide followed by filtration
Answer
Don’t think of neutralization or esterification because they’ll give birth to another product. Filtration will help to remove the sand as a residue while the miscible liquids (water and methanoic ) can be seperated by distillation. ANS is B - An orange drink concentrate is suspected to contain traces of poisonous green dye and a harmless dye having the same boiling point. Which of the following techniques is most suitable for isolating the dyes? A. Fractional distillation B. Paper chromatography C. Coagulation D. Recrystallization
Answer
Please be careful here. The dyes are the solutes carried by the mobile phase (drink). In order to seperate them, paper or partition chromatography is used. Since they’ve the same boiling point fractionalization can’t be used. ANS: B (Paper chromatography) - The separation of petroleum fractions depends on the differences in their A. boiling point B. molar masses C. melting point D. solubilities
Solution
A. Boiling point ( check solution ’35’) - When a substance changes directly from the solid state to the gaseous state without forming a liquid, the substance is said to A. condense B. evaporate C. sublime D. precipitate
Answer
C. Sublime ( check solution ‘5’ ) - Which of the following is a example of a chemical change? A. Dissolution of salt in water. B. Rusting of iron. C. Melting of ice. D. Seperating a mixture by distillation
Answer
B. Rusting of iron - A mixture of common salt, ammonium chloride and barium sulphate can best be separated by. A. Addition of water followed by filtration then sublimation. B. Addition of water followed by sublimation then filtration. C. Sublimation followed by addition of water then filtration. D. Fractional distillation. E. Fractional crystalization
Solution
Sublimation followed by addition of water then filtration.
The first thing is to sublime Ammonium chloride, then add water to filter salt, so as to have barium sulphate as a residue. - Which of the following methods can be used to separate a mixture of two miscibility liquids with different boiling points? A. Decantation. B. Distillation. C. Evaporation. D. Filtration
Answer
Distillation ( check solution’4′) - The order in which a mixture of sand, ammonium chloride and sodium chloride can be seperated is. A. Dissolution→ dryness → filtration→evaporation. B. Filtration→ sublimation→evaporation→dryness. C. Sublimation→dissolution → filtration→ evaporation. D. Dissolution→ filtration →sublimation → evaporation
Answer
Sublimation→dissolution → filtration→ evaporation - Chlorophyll obtained from given leaves of plants can be shown to be composed of more than one coloured components by the technique of. A. Crystallization. B. Hydrolysis. C. Chromatography. D. Sublimation
Answer
Chromatography (c) - Which of the following modes of motion is exhibited by the particles of a solid? A. Vibrational and random motion. B. Vibrational and translational motion. X. Translational and random motion. D. Vibrational motion only. E. Translational motion only
Answer
Vibrational motion only (D) - The purity of a solid sample can best be determined by its. A. Boiling point. B. Melting point. C. Conductivity. D. Solubility
Answer
Melting point - A dye is suspected to have contaminated a lollipop. Which of the following is the best method by which the contaminant may be isolated? A. Fractional distillation. B. Recrystallization. C. Filtration. D. Paper chromatography. E. Evaporation
Answer
Paper chromatography - A mixture of NaCl(s) and CaCO3(s) is best seperated by A. Dissolution followed by filtration. B. Sublimation followed by crystallization. C. Dissolution followed by evaporation. D. Dissolution followed by crystallization. E. Sublimation followed by dissolution
ANS
Dissolution followed by filtration. - Which of the following increases as boiling water changes to steam? A. Temperature of the system. B. Degree of disorder in the system. C. Number of molecules. D. Activation energy
Answer
When change of state occurs, temperature remains constant. Because it is going from liquid to gaseous state, degree of disorder increases in the system. The number of molecules remains constant provided it is a closed system. There’s no need for activation energy, sice it is a physical change [B] - Sugar is seperated from its impurities by A. Precipitation. B. Crystallization. C. Distillation. D. Evaporation
Answer
Crystallization is used to separate sugar from its impurities - A heterogeneous mixture can be defined as any mixture. A. Of a solute and a solvent. B. Whose composition is uniform. C. Whose composition is not uniform. D. Formed by solids and liquids
Answer
A homogeneous mixture is a mixture that exist as a single phase or with uniform composition (e.g air, alloys e.t.c) while heterogeneous mixture exist in More than one phases or non-uniform composition - Which of the following phenomena lead to decrease in volume of a liquid in an open container? A. Brownian motion. B. Diffusion. C. Evaporation. D. Sublimation
Answer
Distillation liquid are recovered but Evaporated liquid are not recovered, so therefore it will continue to reduce the volume of liquid in the container. - Chromatography is used to separate components of mixtures which differ in their rates of. A. Diffusion. B. Migration. C. Reaction. D. Sedimentation. E. Sublimation
Answer
Migration - The heat accompanying the reaction represented by the equation H2O(l) → H2O(g) is described as the heat of A. Solution. B. Neutralization. C. Vaporization. D. Sublimation. E. Activation
Answer
The change of state from liquid to vapour is achieved by the internal heat called the heat of vaporization - When a solid melts and consequently boils, there is. A. A gradual increase in the average kinetic energy of the particles. B. A sudden decrease in the kinetic energy of the particles. C. No Change in the average kinetic energy of the particles. D. A rapid change in the nature of bonding of the components. E. A change in the size of the fundamental particles
Answer
A gradual increase in the average kinetic energy of the particles. - Which of the following changes is physical? A. Adding iron filing to aerated water. B. Adding sodium metal to water C. Cooling a solution of Iron (II) sulphate to obtain the hydrated salt. D. Cooling water to obtain ice E. Burning the domestic gas (Utilgas) for cooking
Answer
Cooling water to obtain ice - Naphthalene when heated melts at 354K (81⁰C). At this temperature the molecules of naphthalene. A. Decompose into smaller molecules. B. Change their shape. C. Are oxidized by atmospheric oxygen. D. Contract. E. Become mobile as the intermolecular forces are broken
Answer
Heating naphthalene breaks the forces and makes the molecules to go wide apart or slide over one another - A sample of orange juice is suspected to have been contaminated with a yellow dye. Which of the following methods can be used to detect the dye? A. Decantation. B. Chromatography. C. Distillation. D. Filtration. E. Evaporation
Answer
Chromatography - In countries where the temperature falls below 273k, salt always spilled on the icy road in order to. A. Increase the melting point of the ice B. Increase the density of the ice. C. Make the ice impure. D. Reduce the melting point of the ice
Answer
Reduce the melting point of the ice - When ammonium chloride is dissolved in water in a test tube, the tube feels colder showing that. A. The solution is unsaturated. B. Sublimation has occurred. C. Ammonia gas is evolved. D. The process is endothermic. E. Condensation has occurred
Answer
The process is endothermic. - The components of the universal indicator solution can best be separated. A. Chromatography B. Filtration. C. Evaporation. D. Crystallization. E. Fractional distillation
Answer
Chromatography - A mixture of kerosene and diesel oil can be separated by. A. Crystallization. B. Distillation. C. Precipitation. D. Sublimation
Solution
They’re miscible liquids, so they can be separated by distillation - By means of filtration, one component can be obtained pure from an aqueous mixture of sodium chloride and A. Potassium nitrate. B. Sand. C. Lead nitrate. D. Sugar (glucose). E. Starch
Answer
All nitrate salts are water soluble. Sugar is water soluble due to multiple hydrogen bonds and polarity. Starch forms a colloidal solution that might not be easily seperated. Aqueous mixture of sand and sodium chloride can be easily seperated. ANS: B - The normal boiling point of a liquid is defined as. A. The temperature at which it’s vapour pressure equals the atmospheric pressure. B. The temperature at which bubbles begin to form. C. the temperature at which the vapour pressure equals 1 temperature. D. The temperature at which the rate of condensation of vapour equals the rate of vaporization of the liquid. E. The temperature at which the space above the liquid is saturated
Answer
A. The temperature at which it’s vapour pressure equals the atmospheric pressure. - Which of the following would support the conclusion that a solid sample is a mixture? A. The solid can be ground to a fine powder. B. The density of the solid is 2.25gdm–³. C. The solid has a melting range of 300⁰C to 375⁰C. D. The solid absorbs mosture from the atmosphere
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The solid has a melting range of 300⁰C to 375⁰C - Which of the following gases is monoatomic? A. Argon. B. Chlorine. C. Nitrogen. D. Oxygen
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Argon - Polyatomicity is illustrated by molecules of. A. Sulphur. B. Carbon (IV) oxide. C. Noble gases. D. Liquefied oxygen. E. Liquefied nitrogen.
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Sulphur - The following gases are diatomic except. A. Nitrogen. B. Helium. C. Hydrogen. D. Fluorine. E. Oxygen
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Helium - Atomicity of ozone is A. 1. B. 2. C. 3. D. 4
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C. 3. I.e O3 - When ice is changing to water, it’s temperature remains the same because the heat gained is. A. Used to separate the molecules. B. Lost partially to the atmosphere. C. Used to increase the volume of ice. D. Less than the activation energy
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Used to separate the molecules. - Which of the following procedures is suitable for identifying the food colouring added to pastry sample? A. Carry out some food tests. B. Examine the pastry sample under a microscope. C. Do a chromotogram of the colouring extract. D. Determine the molar mass of the colouring
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C. Do a chromotogram of the colouring extract.
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