CHM192_PRACTISE TEST/PAST QUESTION

1. In a molecule of CH4, the hydrogen atoms are spatially oriented towards the center of a regular ___________ ANS: tetrahedron 2. When measuring a liquid, you use a_________, and you should also put it on a flat surface and get at _________ level to read it properly. ANS: graduated cylinder, eye 3. What is the appropriate way to test gases for odour? ANS: fan some of the vapour towards your nose 4. How should the meniscus be read? ANS: read the bottom of the meniscus with the eye horizontal to the surface 5. Which equipment can be used for a fire? ANS: fire extinguisher 6. What is the use of a dessicator? ANS: cooling samples 7. The following methods can be used to separate liquids and solids except ANS: distillation 8. Which of these helps you to keep solutions at a constant temperature while stirring? (A)Magnetic stirrer (B) Hot plate stirrer (C)Mechanical stirrer (D)Stirrer motor ANS: B 9. What would you use to achieve a constant stirring? ANS: stirrer motor 10. Which of these is more suitable for accurate measurement of mass? (A)Spring balance (B)Top-loading balance (C)Analytical balance (D)None of the above ANS: C 11. Which of the following can cause error during weighing? (A)Presence of air currents in the lab (B)Balance door being open (C)Non-equilibration of balance (D)All of the above ANS: D 12. What is the maximum capacity of the analytical balance? ANS: 110g 13. ____________ is the maximum capacity of the top- loading machine. ANS: 620g 14. If a procedure tells you to "add about 3 g of ammonium sulphate", which balance would you use? ANS: top loading balance 15. During the same experiment, one must be careful to always use _____________. ANS: different balance CHM192_PRACTISE_SET2 1. If you weighed a hot object on the balance, the reading would be _____________. ANS: lower 2. Which of the following is a recrystallization solvent? (A)Diethylether (B)Ethanol (C)Water (D)All of the above ANS: A 3. What is the meaning of oiling out during recrystallization? ANS: compound melts before dissolving 4. What is the principal purpose of extraction? ANS: to recover a substance from a mixture 5. The following are criteria for selecting an extracting solvent except _____________. (A)It should be insoluble with the solvent of the solution being extracted (B)It should be chemically inert to the extracted substance (C)It should be easily removed from the extracted substance (D)All of the above ANS: D 6. A cube of copper was found to have a mass of 630 g. What are the dimensions of the cube given the density of copper to be 8.94 g/cm3. ANS: 4.13cm 7. You are given a bottle that contains 4.59 cm3 of a metallic solid. The total mass of the bottle is 35.66 g. The empty bottle weighs 14.23 g, what is the density of the solid? ANS: 4.67g{/}cm^{3} 8. Mercury is traded by the "flask", a unit that has a mass of 34.5 kg. What is the volume of a flask of mercury if the density of mercury is 13.6 g/ml? ANS: 2537ml 9. Ethyne gas may be tested for saturation in the laboratory. Which of these is a positive test?(A)It changes the colour of cobalt chloride paper from blue to pink(B)It changes the colour of bromine water from red to blue(C)It turns lime water milky(D)It decolorizes acidified potassium permanganate solution. ANS: D 10. Which of the following features decreases boiling point? (A)Polarity (B)Branching (C)Molecular weight (D)None of the above ANS: B 11. Which of these statements is true? (A)Ethyne will dissolve in water and cyclohexane (B)Ethyne will dissolve in water and dilute hydrochloric acid (C)Ethyne will dissolve in cyclohexane and methyl benzene (D)All of the above ANS: C 12. Which of these properties is considered during recrystallization process? (A)Temperature (B)Pressure (C)Volume (D)Density ANS: A 13. Which of the following is isomeric to pentane?(A)2,2-Dimethylpropane(B)2,2- Dimethylpentane(C)1,1-Dimethylcyclopropane(D)2,3- Dimethylbutane ANS: A 14. Which of the following will undergo an addition reaction with chlorine?(A)Butane(B)Pent-2- ene(C)Benzene(D)Butanoic acid ANS: B 15. What is the expected product formed from the reaction between 2-butene and chlorine? ANS: 2,3-dichlorobutane CHM192_PRACTISE_SET3 1. Why is ethanol not a suitable solvent for extracting aqueous solutions? ANS: Because it is soluble in water 2. What happens when bromine water is added to a saturated hydrocarbon and an unsaturated hydrocarbon? ANS: the colour of bromine water remains unchanged with an unsaturated hydrocarbon but will be decolourised by an unsaturated hydrocarbon 3. Which statement about benzene is correct? (A)Benzene is an isomer of cyclohexane (B)The ratio of carbon to hydrogen atoms in benzene is the same as in ethyne (C)Benzene reacts with bromine solution as if it is saturated (D)Benzene undergoes addition reaction more readily than hexene. ANS: B 4. What is the best treatment for a serious burn? ANS: apply cold compressed air 5. Which of these actions is appropriate in the laboratory? (A)Smoking (B)Eating and Drinking (C)Washing hands frequently (D)Wearing contact lenses ANS: C 6. Which of the following is not a laboratory accident? (A)Cut (B)Heat burn (C)Malaria (D)Chemical burn ANS: C 7. What should you do if a chemical gets into your eye? ANS: flush with gently flowing water for 15 minutes 8. Which of these can be used to measure mass? (A)Graduated cylinder (B)Conical flask (C)Balance (D)Ruler ANS: C 9. What is the unit for measuring length? ANS: meter 10. Which of these flasks is useful in a distillation process? (A)Erlenmeyer flask (B)Round-bottom flask (C)Filter flask (D)Conical flask ANS: B 11. Which of the following is used to separate two immiscible liquids? (A)Buchner funnel (B)Filter flask (C)Conical flask (D)Separatory funnel ANS: D 12. When is the best time to clean glass wares? ANS: immediately after use 13. Which of the following is a dessicant used in the laboratory? (A)Drier (B)Silica gel (C)Ammonia (D)Carbonmonoxide ANS: B 14. Which of these is not a component of the bunsen burner? (A)Chimney (B)Needle valve (C)Tube (D)Air vent ANS: C 15. Name the apparatus used to crush solids into powder for experiments. ANS: mortar and pestle CHM192_PRACTISE_SET4 1. Which element is present in all organic compounds? (A)Nitrogen (B)Oxygen (C)Carbon (D)Phosphorus ANS: C 2. Which statement explains why the element "Carbon" forms so many compounds? (A)Carbon atoms combine readily with Oxygen (B)Carbon atoms have very high electronegativity (C)Carbon atoms readily form ionic bonds with other carbon atoms (D)Carbon atoms readily form covalent bonds with other carbon atoms ANS: D Emostel Academy CHM192 iLearn Questions and Answers 4 info@emostelacademy.com|www.emostelacademy.com|08089896529, 08067481833 DISCLAIMER: FOR REVISION PURPOSE ONLY, PLEASE DO NOT TAKE TO THE EXAM HALL 3. What is the name of the compound that has the molecular formula C6H6? ANS: benzene 4. The following except one will help to view the meniscus correctly? (A)Dim lighting (B)Proper lighting (C)Eye level viewing (D)White background ANS: A 5. Breaking of a larger hydrocarbon molecule into a smaller one by heating in the presence of a catalyst is called ___. ANS: cracking 6. Which of these compounds is a saturated hydrocarbon? (A)Ethane (B)Ethene (C)Ethyne (D)Ethanol ANS: A 7. Which molecule contains a total of three carbon atoms? (A)2-methyl propane (B)2-methyl butane (C)Propane (D)Butane ANS: C 8. The representation CH3CH2CH2CH2CH3 for the alkane pentane is an example of ____________ ANS: condensed formula 9. Which of these funnels is used in suction filtration? (A)Buchner funnel (B)Filter funnel (C)Long stem funnel (D)Separatory funnel ANS: A 10. Which of these is useful in suction filtration set ups? (A)Round-bottom flask (B)Evaporating dish (C)Filter flask (D)Beaker ANS: C 11. The melting point of ice is ___________. ANS: 0^{o}C 12. The S.I unit of heat is ____________. ANS: joule 13. If you weighed a hot object on the balance, the reading would be _____________. ANS: lower 14. If you weighed a cold object on the balance, the reading would be _____________. ANS: higher 15. ____________ of a liquid is the temperature at which the vapour pressure equals atmospheric pressure. ANS: boiling point CHM_PRACTISE_SET5 1. Solids are purified through ___________. ANS: recrystallization 2. A small amount of impurity ___________ the boiling point of an organic compound. ANS: increases 3. Freezing points are difficult to determine because of the phenomenon of ___________ ANS: super cooling 4. The process of going from a solid, directly to a gasseous state is called ___________. ANS: sublimation 5. The phenomenon whereby a solid suddenly shrinks before melting is termed ___________ ANS: sintering 6. ____________ is the boiling point of water. ANS: 100^{o}C Emostel Academy CHM192 iLearn Questions and Answers 5 info@emostelacademy.com|www.emostelacademy.com|08089896529, 08067481833 DISCLAIMER: FOR REVISION PURPOSE ONLY, PLEASE DO NOT TAKE TO THE EXAM HALL 7. __________ layers are usually formed in a separating funnel. ANS: two 8. Isomers have the same _____________. ANS: molecular formula 9. Dehydration of an alcohol leads to the formation of an ____________. ANS: alkene 10. The boiling point of ethanol is __________. ANS: 78.3^{o}C 11. ____________ is used to heat and evaporate liquids. ANS: bunsen burner 12. The bunsen burner is named after _____________. ANS: Robert Bunsen 13. _____________ of a liquid is the temperature at which the vapour pressure equals the applied pressure. ANS: The boiling point 14. Branching ________ boiling point ANS: decreases 15. Increased molecular weight _________ boiling point ANS: increases CHM192_PRACTISE_SET6 1. Ethane is a ____________ hydrocarbon. ANS: saturated 2. ____________ gives the accurate measurement of mass. ANS: analytical balance 3. _________ occurs when a liquid is cooled below its freezing point and does not solidify. ANS: supercooling 4. Hydrocarbons containing at least one carbon-to- carbon double bond are called _________. ANS: alkenes 5. Hydrocarbons with at least one carbon-to-carbon triple bond are called ____________. ANS: alkynes 6. The separatory funnel is used to separate two ____________ liquids. ANS: immiscible 7. The unit of length is _________________. ANS: meter 8. The maximum capacity of the analytical balance is ____________. ANS: 110g 9. ___________ is the breaking of a larger hydrocarbon molecule into a smaller one by heating in the presence of a catalyst ANS: cracking 10. Short-fitted clothes are proper apparel for the laboratory. True or false?_________ ANS: false 11. A small amount of impurity ________ the melting point of an organic compound. ANS: reduces 12. The phenomenon whereby solids pass directly from the solid state to the gaseous state is termed ___________ ANS: sublimation 13. ___________ is used for holding and organizing test tubes on the laboratory counter. ANS: clamp 14. ____________ is used to hold flasks and crucibles when they are hot. ANS: crucible tong 15. During the same experiment, one must be careful to always use _____________balance. ANS: different CHM192_PRACTISE_SET7 Emostel Academy CHM192 iLearn Questions and Answers 6 info@emostelacademy.com|www.emostelacademy.com|08089896529, 08067481833 DISCLAIMER: FOR REVISION PURPOSE ONLY, PLEASE DO NOT TAKE TO THE EXAM HALL 1. If the density of a solid is less than the liquid medium in which it is immersed, the object will ____________. ANS: float 2. The loss of water from a molecule is called ____________. ANS: dehydration 3. ___________ is used to provide heat for experimentation ANS: Bunsen burner 4. The process by which a substance moves from liquid state to gas state is called ___________. ANS: vapourisation 5. Sublimation and decomposition points are useful in establishing the purity of a compound. True or false? __________ ANS: false 6. The maximum capacity of the analytical balance is ___________. ANS: 110 g 7. An isomer of n-butane is ___________. ANS: 2-methylpropane 8. Hydrocarbons that contain only carbon-to-carbon single bonds are called ____________. ANS: alkanes 9. A hot object has a lower temperature than a cold one. True or false? __________ ANS: false 10. ___________ is a measure of the degree of hotness of an object. ANS: Temperature 11. In the metric system, the basic unit of mass is the ____________. ANS: gramme 12. If the density of a solid is greater than the liquid medium in which it is immersed, the object will ____________. ANS: sink 13. When salt is added to water, its melting point ___________. ANS: reduces 14. For correct determination of boiling point of water , we should note reading when temperature starts rising. True or false? ______ ANS: true 15. The boiling point of salty water will be _________ than the boiling point of pure water. ANS: higher CHM192_PRACTISE_SET8 1. A volatile liquid has a high boiling point. True or false? _____________ ANS: false 2. The ratio of carbon to hydrogen atoms in benzene is the same as in ethyne. True or false? _______ ANS: true 3. For safety in the lab, long hair needs to be tied back. True or false? __________ ANS: true 4. __________ is used to remove solid chemicals from a bottle. ANS: Spatula 5. Insoluble impurities have no effect on melting point. True or false? _________ ANS: true 6. The ____________ of a solid is defined as the temperature at which the liquid and solid phases are in equilibrium. ANS: melting point