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Grade 12 Chemistry national exam, 2016 E.C. (2024 G.C.)
73 questions · 120 minutes. The first 5 answers are shown with explanations; sit the whole paper timed in the app to get your score and the textbook page behind every question.
- 1.What are the molecular formulae of an alkene and alkyne containing seven carbon atoms, respectively?
- A. C 7 H 14 and C 7 H 12
- B. C 7 H 16 and C 7 H 14
- C. C 7 H 14 and C 7 H 16
- D. C 7 H 12 and C 7 H 14
Answer: A. The question tests the general formulas for alkenes and alkynes. For seven carbon atoms, an alkene has formula $\mathrm{C_nH_{2n}}$, giving $\mathrm{C_7H_{14}}$; an alkyne has formula $\mathrm{C_nH_{2n-2}}$, giving $\mathrm{C_7H_{12}}$. B and C use the wrong hydrogen numbers, while D gives the alkyne and alkene formulas in the wrong order. Textbook: Grade 10, unit 6 · section 6.3. - 2.Which of the following is the CORRECT method of preparation of alkenes in the laboratory?
- A. Alkylation of sodium acetylide with a primary alkyl halide.
- B. Heating of sodium salt of an organic acid with soda lime.
- C. Reaction of halogenated alkane with sodium.
- D. Dehydration of alcohols with concentrated sulfuric acid.
Answer: D. The key idea is that alcohols can form alkenes by losing water. Heating an alcohol with concentrated sulfuric acid removes water and forms an alkene, so D is correct. A prepares an alkyne; B prepares an alkane; C is a method for making alkanes, not alkenes. Textbook: Grade 10, unit 6 · section 6.2. - 3.Which of the following is the CORRECT structure of benzene?
- 4.What is the molecular formula and IUPAC name of a saturated monocarboxylic acid having six carbon atoms?
- A. C 5 H 11 COOH, heptanoic acid
- B. C 6 H 13 COOH, heptanoic acid
- C. C 5 H 11 COOH, hexanoic acid
- D. C 6 H 13 COOH, hexanoic acid
Answer: C. For a carboxylic acid, count the carbon in the $\mathrm{COOH}$ group as well as the other carbons. In C, $5+1=6$ carbons, so $C_5H_{11}COOH$ has molecular formula $C_6H_{12}O_2$ and is hexanoic acid. A has the right six-carbon formula, but heptanoic acid has seven carbons. B has seven carbons, so it does not fit the question. D also has seven carbons, and its name hexanoic acid does not match that formula. Textbook: Grade 11, unit 6 · section 6.4. - 5.During summer, the average value for the temperature measured in a certain chemistry laboratory is 298.15 K. How many decimal places are there in the measured value?
- A. 5
- B. 3
- C. 2
- D. 1
Answer: C. The key idea is that decimal places count the digits to the right of the decimal point. The value $298.15\,\mathrm{K}$ has two digits after the decimal point. A and B count too many places; D counts too few. Textbook: Grade 9, unit 2 · section 2.1. - 6.Given the following structure: What is the IUPAC name for the above structure?
- A. Methyl ethanoate
- B. Ethyl ethanoate
- C. Propyl formate
- D. Ethyl acetate
- 7.A student collected four beakers in his/her laboratory and added some small amounts of the following: naphthalene to the first, graphite to the second, iodine to the third and alcohol to the fourth. If they added equal volume of water to each of the above beakers and shake each beaker, which of the following will be their observation?
- A. There will be dissolution in the first three beakers.
- B. Water will dissolve iodine rather than graphite.
- C. Water will dissolve the whole given chemicals in the four beakers.
- D. There will be dissolution of alcohol in the fourth beaker.
Answer: D. This question tests which substances mix with water. Alcohol mixes with water, so it dissolves in the fourth beaker. A is wrong because naphthalene and graphite do not dissolve in water; B is wrong because iodine dissolves only very slightly, not enough to count as dissolving in this observation; C is wrong because not all four substances dissolve. Textbook: Grade 11, unit 2 · section 2.3. - 8.Which of the following explanations about reversible and irreversible reactions is CORRECT?
- A. A reaction that has only a forward reaction or a reverse reaction is known as a reversible chemical reaction.
- B. A reaction that proceeds from reactant to product and from product to reactant is known as an irreversible reaction.
- C. Chemical reactions that proceed only towards the formation of a product are known as irreversible reactions.
- D. Chemical reactions that proceed only towards the formation of a product are known as reversible reactions.
Answer, explanation and textbook page: open in the app. - 9.Consider the following three steps: Step 1 : Electrolysis of water and fractional distillation of air Step 2 : Passing hot mixture of gases through a condenser Step 3 : Introducing hydrogen and nitrogen gases in a chamber containing iron particles at a temperature of 300 - 500 °C and a pressure of 15 - 25 MPa Which of the following is the CORRECT sequence involved during the industrial production of ammonia using the Haber process?
- A. Step 1 → Step 3 → Step 2
- B. Step 2 → Step 3 → Step 1
- C. Step 2 → Step 1 → Step 3
- D. Step 1 → Step 2 → Step 3
Answer, explanation and textbook page: open in the app. - 10.Which of the following is a physical property of nitric acid, HNO 3 ?
- A. On exposure to light, it turns brown.
- B. Nitric acid is a corrosive chemical.
- C. Nitric acid has a pungent smell.
- D. It forms large number of salts.
Answer, explanation and textbook page: open in the app. - 11.Which of the following is the CORRECT explanation about herbicides?
- A. Selective herbicides control specific weed species, leaving the desired crop unharmed.
- B. Organochlorine compounds are the most common herbicide substances.
- C. Herbicides are substances that are used to control unwanted insects.
- D. Herbicides are substances that are used to enhance the growth of important plants.
Answer, explanation and textbook page: open in the app. - 12.A student collected the following information from the community on the preparation of the local alcoholic drink "ARAKI": Step 1 : Distillation of the liquid mixture in traditional ways Step 2 : Adding a proportional amount of water to liquidity the tick dough - like mixture and leaving for 1-2 days for further fermentation Step 3 : "Bikel" preparation from barely, the starter ("Tinsess") preparation by mixing the Bikel with Gesho (Rhamunspronoides) powder and fermentation of the starter for few days Step 4 : Baking of bread from different ingredients and breaking down the bread and mixing with the fermented starter and leaving for fermentation for couple of days Which of the following is the correct procedure for the preparation of Araki?
- A. Step 2 → Step 4 → Step 3 → Step - 1
- B. Step 2 → Step 3 → Step 4 → Step - 1
- C. Step 3 → Step 4 → Step 2 → Step - 1
- D. Step 4 → Step 3 → Step 2 → Step - 1
Answer, explanation and textbook page: open in the app. - 13.Which one of the following synthetic polymers is used to make squeeze bottles, plastic wrapping and electrical insulation?
- A. Polypropylene
- B. Polymethyl methacrylate
- C. Polyvinylchloride
- D. Polyethylene
Answer, explanation and textbook page: open in the app. - 14.Which of the following descriptions of the property of a covalent compound is CORRECT?
- A. Covalent compounds have low melting and boiling points.
- B. Most covalent compounds are solids at room temperature.
- C. Most covalent compounds are soluble in water.
- D. Covalent compounds are non-volatile.
Answer, explanation and textbook page: open in the app. - 15.The attractive force between molecules is known as _________.
- A. nuclear force
- B. intermolecular force
- C. lattice force
- D. intramolecular forces
Answer, explanation and textbook page: open in the app. - 16.The hybridization of the central atom xenon (Xe) in xenon tetraflouride, XeF 4 , is sp 3 d 2 . Which of the following is the shape of XeF 4 ?
- A. Octahedral
- B. Square planar
- C. Tetrahedral
- D. Seesaw shape
Answer, explanation and textbook page: open in the app. - 17.Consider the following reaction between nitrogen (N 2 ) and oxygen (O 2 ): N 2 (g) + O 2 (g) → 2NO(g) If the rate of disappearance of N 2 is 2.5 x 10 -6 M/s, what is the rate of reaction for the formation of NO?
- A. 5.0 x 10 -6 M/s
- B. 1.25 x 10 -3 M/s
- C. 2.50 x 10 -3 M/s
- D. 2.50 x 10 -6 M/s
Answer, explanation and textbook page: open in the app. - 18.Which of the following is a Lewis acid?
- A. SO 4 2-
- B. SO 3 2-
- C. BF 3
- D. NH 3
Answer, explanation and textbook page: open in the app. - 19.Which of the following is the CORRECT electron configuration of a peroxide ion, O 2 2- ?
- A. (σ 11 ) 2 (σ* 1s ) 2 (σ 2s ) 2 (σ* 2s ) 2 (σ 2px ) 2 (π 2py 2 = π 2pz 2 )(π* 2py = π* 2pz ) 2 (σ* 2z ) 2
- B. (σ 11 ) 2 (σ* 1s ) 2 (σ 2s ) 2 (σ* 2s ) 2 (σ 2px ) 2 (π 2py 2 = π 2pz 2 )(π* 2py = π* 2pz ) 2 (σ* 2z )
- C. (σ 11 ) 2 (σ* 1s ) 2 (σ 2s ) 2 (σ* 2s ) 2 (σ 2px ) 2 (π 2py 2 = π 2pz 2 )(π* 2py = π* 2pz ) 2 (σ* 2z ) 2
- D. (σ 11 ) 2 (σ* 1s ) 2 (σ 2s ) 2 (σ* 2s ) 2 (σ 2px ) 2 (π 2py 2 = π 2pz 2 )(π* 2py = π* 2pz ) 2 (σ* 2z )
Answer, explanation and textbook page: open in the app. - 20.The shift in the position of equilibrium caused by the addition of an ion already involved in the reaction is known as _________.
- A. common-ion effect
- B. buffer-ion effect
- C. hydrolysis-effect
- D. titration-effect
Answer, explanation and textbook page: open in the app. - 21.Which of the following is CORRECT about equivalents of acids and bases?
- A. The volume of an acid or base required to reach equivalence point during acid-base titration reaction.
- B. The number of moles of an acid or base required to form a one molar aqueous acidic or basic solution.
- C. It is the amount of a substance that is required to react with one mole of hydroxide ions in redox reactions.
- D. It is the amount of a substance that is required to react with one mole of hydrogen ions in acid-base reactions.
Answer, explanation and textbook page: open in the app. - 22.A 250 mL solution is formed from 24.5 g of sulfuric acid (H 2 SO 4 ). What is the normality of this solution? (Mol. wt. H 2 SO 4 = 98 g/mol)
- A. 4.00 N
- B. 2.00 N
- C. 0.250 N
- D. 0.125 N
Answer, explanation and textbook page: open in the app. - 23.Which of the following reaction is used for the preparation of bases?
- A. Reaction of metal hydroxides with dilute acids.
- B. Reaction of active metal oxides with water
- C. Heating of a salt with a non-volatile acid.
- D. Heating of carbonates with dilute acids.
Answer, explanation and textbook page: open in the app. - 24.Which of the following salts is used in the treatment of waste water?
- A. CaCO 3
- B. BaSO 4
- C. FeCl 3
- D. KNO 3
Answer, explanation and textbook page: open in the app. - 25.A student prepared two beakers, each containing 100 mL of water. The student dissolved 10 mL of concentrated HCl in the first beaker and 10 mL of concentrated CH 3 COOH in the second beaker, which of the following would occur in the solution?
- A. In the first beaker, a large fraction of HCl dissociates into ions and in the second beaker, a small fraction of CH 3 COOH dissociates into ions.
- B. In the first beaker, a small fraction of HCl dissociates into ions and in the second beaker, a large fraction of CH 3 COOH dissociates into ions.
- C. There is no dissociation or ionization of the HCl and CH 3 COOH in both the first and second beakers.
- D. The amount of HCl dissociated in the first beaker and the amount of CH 3 COOH dissociated in the second beaker are identical.
Answer, explanation and textbook page: open in the app. - 26.Consider the following five-steps during the extraction of aluminum from its bauxite ore by the Hall process: I. Treating the mixture of an aqueous solution of sodium silicate and aluminate with an acid II. Heating aluminum oxide strongly in a furnace III. Heating the ore with sodium hydroxide solution IV Conversion of aluminum oxide to soluble sodium aluminate V. Electrolysis of molten mixture of cryolite and aluminum oxide Which of the following is the CORRECT sequence of production?
- A. III, IV, I, II and V
- B. IV, II, I, III and V
- C. V, I, II, IV and III
- D. II, I, III, IV and V
Answer, explanation and textbook page: open in the app. - 27.Which of the following food preservation methods leaves a product without loss of aroma or flavor?
- A. Vacuum-packing
- B. Freeze-drying
- C. Freezing
- D. Melting
Answer, explanation and textbook page: open in the app. - 28.The electronic configuration of an element in the periodic table is 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 5 . In which block does this element belong?
- A. f-block
- B. d-block
- C. p-block
- D. s-block
Answer, explanation and textbook page: open in the app. - 29.Which of the following is CORRECT about the formation of a covalent bond? A covalent bond is formed
- A. between positively and negatively charged ions.
- B. between mobile and stationary electrons.
- C. by the sharing of valence electrons.
- D. by the transfer of valence electrons.
Answer, explanation and textbook page: open in the app. - 30.The molecule of carbon tetrachloride (CCl 4 ) has four polar (C - Cl) bonds. However, CCl 4 is a non-polar molecule. Which of the following explains the reason for the observed property of CCl 4 ?
- A. The molecule is non-polar because of the presence of four polar C-Cl bonds in the molecule.
- B. The molecule is non-polar because of the difference in electronegativity between carbon and chlorine.
- C. Even though the bond in CCl 4 is polar, the net dipole moment of the molecule is different from zero.
- D. Even though the bond in CCl 4 is polar, the net dipole moment of the molecule is zero.
Answer, explanation and textbook page: open in the app. - 31.Which of the following is responsible for the unusual high boiling points of HF, H 2 O and NH 3 ?
- A. London dispersion forces
- B. Hydrogen bonding
- C. Covalent bonding
- D. Ionic bonding
Answer, explanation and textbook page: open in the app. - 32.Consider the following chart of general periodic properties in the periodic table. From the given periodic properties, which one CORRECTLY agrees with the periodic trend in the chart?
- A. Electronegativity
- B. Electron affinity
- C. Ionization energy
- D. Atomic radius
Answer, explanation and textbook page: open in the app. - 33.Which of the following is CORRECT about the phase change observed in water?
- A. Water starts to evaporate at the boiling point and condenses at the melting point.
- B. When a solid ice is heated, it is changed to liquid water without melting.
- C. At the boiling point temperature, water exists in three different physical states.
- D. At the melting point of ice, the temperature remains constant.
Answer, explanation and textbook page: open in the app. - 34.Given the symbols of the three subatomic particles; electrons (e - ), protons (p + ) and neutrons (n 0 ), which of the following is the CORRECT comparison of the absolute masses of protons, electrons and neutrons?
- A. Mass of e - > mass of p + = mass of n 0
- B. Mass of e - = mass of p + > mass of n 0
- C. Mass of e - < mass of p + < mass of n 0
- D. Mass of e - > mass of p + > mass of n 0
Answer, explanation and textbook page: open in the app. - 35.In the modern periodic table, what is the name of the group that contains the most electronegative elements?
- A. Alkali
- B. Halogens
- C. Chalcogens
- D. Noble gases
Answer, explanation and textbook page: open in the app. - 36.A given element has atomic number of 55 and mass number of 133. Which of the following describes CORRECTLY the property of this element?
- A. The non-metallic character of the element is high.
- B. The metallic character of the element is high.
- C. The element has high electron affinity.
- D. The element has high electronegativity.
Answer, explanation and textbook page: open in the app. - 37.Consider the mechanism for the decomposition of N 2 O 5 to NO 2 : First step: 2N 2 O 5 (g) = 4NO 2 (g) Second step: N 4 O 10 (g) → NO 3 (g) + 2 NO 2 (g) + O 3 (g) Third step: N 2 O 5 (g) + O 3 (g) → 2 NO 2 (g) + O 2 (g) Overall: 2N 2 O 5 (g) → 4 NO 2 (g) + O 2 (g) Which step is the rate-determining step?
- A. Third step
- B. First step
- C. The overall step
- D. Second step
Answer, explanation and textbook page: open in the app. - 38.Consider the following reaction: N 2 (g) + O 2 (g) = 2NO(g) The equilibrium concentrations of gaseous nitrogen, oxygen and nitrogen monoxide in a sealed container are as follows: [N 2 ] = 1 x 10 -3 M, [O 2 ] = 2 x 10 -5 M and [NO] = 4 x 10 -5 M. What is the value of the equilibrium constant for the reaction?
- A. 8
- B. 2
- C. 16
- D. 4
Answer, explanation and textbook page: open in the app. - 39.At a certain temperature the following reaction has an equilibrium constant Kc = 12.4. N 2 (g) + 3H 2 (g) ⇌ 2NH 3 (g) If [N 2 ] = 2.0 M, [H 2 ] = 2.0 M and [NH 3 ] = 10.0 M, to which direction will the reaction proceed to reach equilibrium?
- A. The reaction will proceed to the reverse direction.
- B. The reaction is at a chemical equilibrium.
- C. The equilibrium is independent of the concentration.
- D. The reaction will proceed to the forward direction.
Answer, explanation and textbook page: open in the app. - 40.Upon standing long, "Tella" or "Tej" turns sour. Which of the following is the CORRECT explanation for the observed effect?
- A. The reduction of alcohol to an acid.
- B. The oxidation of alcohol to an acid.
- C. Addition reaction of alcohol with an acid.
- D. Decomposition reaction of alcohol.
Answer, explanation and textbook page: open in the app. - 41.A student is interested in determining the content of a leaf from his/her environment and performed the following: Step: 1 He/she dried the leaves up in sun light Step: 2 Evaluated the work and draw conclusions Step: 3 Collected leaves from the tree around his village Step: 4 He/she boiled the leaves and collected the leaves extracted Step: 5 Analyze the content of the leaves extracted using an instrument Which of the following is the CORRECT procedure if a student developed an experimental skill?
- A. Steps: 3 → 5 → 4 → 1 → 2
- B. Steps: 3 → 4 → 1 → 5 → 2
- C. Steps: 3 → 1 → 4 → 5 → 2
- D. Steps: 3 → 1 → 5 → 4 → 2
Answer, explanation and textbook page: open in the app. - 42."The hydrogen atom moves in a fixed circular orbit associated with allowable energy states" This is called ____.
- A. Planck's theory
- B. Bohr's theory
- C. Pauli's principle
- D. Aufbau's principle
Answer, explanation and textbook page: open in the app. - 43.Which of the following is the core electron configuration of the metal ion in ferric sulfate, Fe 2 (SO 4 ) 3 ? (Atomic Number of Fe = 26)
- A. [Ar]4s 2 3d 6
- B. [Ar]4s 1 3d 6
- C. [Ar]3d 6
- D. [Ar]3d 5
Answer, explanation and textbook page: open in the app. - 44.A chemical bond that results from the attractive force between shared electrons and nonmetal nucleus is called _____.
- A. covalent bond
- B. ionic bond
- C. hydrogen bond
- D. metallic bond
Answer, explanation and textbook page: open in the app. - 45.Which of the following is peroxide?
- A. ZnO
- B. FeO
- C. K 2 O
- D. CaO 2
Answer, explanation and textbook page: open in the app. - 46.Among the following which one is a ternary acid?
- A. HBr
- B. HCl
- C. H 2 SO 4
- D. H 2 S
Answer, explanation and textbook page: open in the app. - 47.Which of the following characteristics of an electromagnetic radiation is CORRECT?
- A. The speed of an electromagnetic radiation decreases with increase in its wavelength.
- B. The speed of an electromagnetic radiation increases with increase in its frequency.
- C. The speed of an electromagnetic wave is independent of the nature of the medium it travels through.
- D. The wave length of an electromagnetic radiation is directly proportional to its frequency.
Answer, explanation and textbook page: open in the app. - 48.The hydrogen ion concentration in a certain solution at 25 °C is 10 × 10 -6 M. What is the pH of this solution?
- A. 8
- B. 10
- C. 2
- D. 6
Answer, explanation and textbook page: open in the app. - 49.Given the following oxidation-reduction reaction: H 2 S + HNO 3 → S + NO + H 2 O Which of the following is CORRECT from the given equation?
- A. The oxidation number of N is increased.
- B. The oxidation number of S is decreased.
- C. S is a reducing substance.
- D. HNO 3 is an oxidizing agent.
Answer, explanation and textbook page: open in the app. - 50.Consider the following diagram of an electrolytic cell: Which of the following is CORRECT from the given diagram
- A. Oxidation takes place at the cathode.
- B. Reduction takes place at the anode.
- C. Magnesium ion is oxidizing agent in the electrode reaction.
- D. There is a decrease in oxidation number of chloride ion.
Answer, explanation and textbook page: open in the app. - 51.Which of the following is CORRECT about molten electrolytes and aqueous electrolytes?
- A. The possible half reactions in molten electrolytes are more compared to aqueous electrolytes.
- B. Both molten and aqueous electrolytes involve preferential discharge of ions at each electrode.
- C. An electrolyte that conducts electricity when dissolved in a certain liquid is molten electrolyte.
- D. During the electrolysis of a molten electrolyte, the reduction of cations occurs at the cathode.
Answer, explanation and textbook page: open in the app. - 52.Which of the following is NOT the industrial application of electrochemistry?
- A. Electrolytic refining
- B. Electroplating
- C. Electromagnetism
- D. Electro synthesis
Answer, explanation and textbook page: open in the app. - 53.A student collected few leaves from his/her backyard, brought it to their class and prepared a litmus paper since in a beaker. They got blue and red litmus papers from his/her teacher and placed few drops of the beaker liquid on the litmus papers. What will be their observations on the litmus papers?
- A. The blue litmus paper as well as the red litmus paper will maintain their color.
- B. The blue litmus paper and the red litmus paper will turn colorless.
- C. The red litmus paper will turn to blue and the blue litmus paper will maintain its color.
- D. The blue litmus paper will turn red and the red litmus paper will maintain its color.
Answer, explanation and textbook page: open in the app. - 54.A student added 25 mL of AgNO 3 solution to a beaker and weighed the mass of the beaker and its content as m 1 . He/she added 50 mL of a saturated solution of NaCl into the second beaker and weighed the mass of the beaker and its content as m 2 . Finally, he/she mixed the two solutions and weighed the mass of the resulting solution with the two beakers and recorded as m 3 . If he/she found that m 1 = m 2 , which one of the following laws is investigated by this trial?
- A. Law of definite composition
- B. Law of multiple proportions
- C. Law of conservation of energy
- D. Law of conservation of mass
Answer, explanation and textbook page: open in the app. - 55.A chemical reaction that releases heat energy to the surrounding is known as _____.
- A. exothermic reaction
- B. endothermic reaction
- C. decomposition reaction
- D. combination reaction
Answer, explanation and textbook page: open in the app. - 56.A type of reaction in which two compounds react together to form two or more products by exchanging reactants ions is known as _____________.
- A. Decomposition reaction
- B. Combination reaction
- C. Double Displacement reaction
- D. Single Displacement reaction
Answer, explanation and textbook page: open in the app. - 57."At a given temperature and pressure, equal volumes of different gases contain equal number of molecules", this is known as _______
- A. Charle's law
- B. Boyle's law
- C. Gay Lussac's law
- D. Avogadro's law
Answer, explanation and textbook page: open in the app. - 58.Which of the following includes the preconditions required for a chemical reaction to occur?
- A. Temperature, activation energy, proper orientation
- B. Temperature, pressure and proper orientation
- C. Activation energy, proper orientation and collision between reactants
- D. Activation energy, pressure and collision between reactants
Answer, explanation and textbook page: open in the app. - 59.Consider the following reaction of zinc carbonate, ZnCO 3 : ZnCO 3 (s) → ZnO(s) + CO 2 (g) The chemical reaction that takes place during the conversion of ZnCO 3 is classified as
- A. decomposition reaction
- B. combination reaction
- C. double displacement reaction
- D. single displacement reaction
Answer, explanation and textbook page: open in the app. - 60.Given the following reaction: CaCO 3 + HCl → CaCl 2 + CO 2 + H 2 O (unbalanced) If 40 g of CaCO 3 reacts with 30 g of HCl, which substance is the limiting and which is the excess reagent? (Atomic Mass: Ca=40 g/mol, C=12 g/mol, O=16 g/mol, H=1 g/mol and Cl=35.5 g/mol)
- A. HCl is limiting and CaCl 2 is excess reagents.
- B. HCl is limiting and CaCO 3 is excess reactants.
- C. CaCO 3 is limiting and CaCl 2 is excess reagents.
- D. CaCO 3 is limiting and HCl is excess reactants.
Answer, explanation and textbook page: open in the app. - 61.A sample of a certain gas has a volume of 100 L at 27 °C and 750 torr. The gas is expanded to a volume of 250 L at 200 torr. What is the final temperature of the gas?
- A. -83 °C
- B. -73 °C
- C. -17 °C
- D. -273 °C
Answer, explanation and textbook page: open in the app. - 62.Which of the following is a CORRECT explanation of the given term?
- A. Boiling point is the temperature at which the vapor pressure of the liquid equals the atmospheric pressure.
- B. Condensation is the process by which a liquid changes to a gas at the boiling point of the liquid.
- C. Normal boiling point is the temperature at which the liquid starts to be converted to the gaseous state.
- D. Heat of vaporization is the energy required to convert one gram of a solid to a gas at its boiling point.
Answer, explanation and textbook page: open in the app. - 63.Which of the following is the general formula of alkenes?
- A. C n H 2n-2
- B. C n H 2n+2
- C. C n H n
- D. C n H 2n
Answer, explanation and textbook page: open in the app. - 64.What are the two types of polymerizations?
- A. Condensation and substitution polymerizations
- B. Addition and decomposition polymerizations
- C. Condensation and displacement polymerizations
- D. Addition and condensation polymerizations
Answer, explanation and textbook page: open in the app. - 65.Which of the following is a monomer of natural rubber?
- A. Ethylene terephthalate
- B. Styrene
- C. Hexamethylene diamine
- D. Isoprene
Answer, explanation and textbook page: open in the app. - 66.The component of the environment consisting earth's upper outer most skin, and accessible to human beings is known as _____.
- A. biosphere
- B. lithosphere
- C. hydrosphere
- D. atmosphere
Answer, explanation and textbook page: open in the app. - 67.Consider the following steps that occur during the nitrogen cycle: Step: 1 Reduction of nitrate by microbial action Step: 2 Fixation of nitrogen by bacteria and algae Step: 3 Nitrification by nitrososnas and nitrobactra Step: 4 Denitrification of nitrate with acid and formaldyde Which of the following is the CORRECT sequence in the nitrogen cycle?
- A. Step 2 → Step 3 → Step 4 → Step 1
- B. Step 1 → Step 2 → Step 3 → Step 4
- C. Step 2 → Step 3 → Step 1 → Step 4
- D. Step 1 → Step 3 → Step 4 → Step 2
Answer, explanation and textbook page: open in the app. - 68.Some hazardous substances damage and create unwanted changes in air, water, soil or any other natural resource. The resulting change created is known as:
- A. afforestation
- B. pollution
- C. greenhouse effect
- D. global warming
Answer, explanation and textbook page: open in the app. - 69.Given the following heterogeneous reaction: CaCO 3 (s) ⇌ CaO (s) + CO 2 (g) What is the equilibrium constant expression for the above reaction?
- A. K c = [CaO][CO 2 ]
- B. K c = [CaO][CO 2 ]/[CaCO 3 ]
- C. K c = [CO 2 ]
- D. K c = [CaO]/[CaCO 3 ]
Answer, explanation and textbook page: open in the app. - 70.Which of the following statements is CORRECT regarding the properties of monocarboxylic acids?
- A. Carboxylic acids react with active metals to form salt and hydrogen gas.
- B. The hydrolysis of carboxylic acids in water produces an ester and water.
- C. Carboxylic acids react with strong bases to form esters and water.
- D. Heating of carboxylic acid with alcohol produces salt and water.
Answer, explanation and textbook page: open in the app. - 71.A water molecule has two bond pairs and two lone pairs of electrons. Which of the following is CORRECT about these pairs of electrons?
- A. The repulsion between the two bonding pairs is greater than the repulsion between the two lone pairs.
- B. The repulsion between the two lone pairs is greater than the repulsion between the two bonding pairs.
- C. Bonding pair - lone pair repulsion is greater than lone pair - lone pair repulsion.
- D. Lone pair - lone pair repulsion is exactly identical with bonding pair - bonding pair repulsion.
Answer, explanation and textbook page: open in the app. - 72.Which of the following CORRECTLY describes conjugate acids and conjugate bases?
- A. Conjugate acid is a species formed after a removal of a proton from a base whereas conjugate base is formed after addition of proton to an acid.
- B. Conjugate base is a species formed after removal of a proton from an acid whereas conjugate acid is formed after addition of a proton to a base.
- C. Conjugate acid has one fewer hydrogen and one more minus charge than the corresponding acid.
- D. Conjugate base has one more hydrogen and one fewer minus charge than the corresponding base.
Answer, explanation and textbook page: open in the app. - 78.What is the scientific notation for 0.00 30055?
- A. 55 x 10^-7
- B. 5.5x10^-6
- C. 55 x 10^-5
- D. 5.5 x 10^-4
Answer, explanation and textbook page: open in the app.