Chemistry Choice Questions - 2


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Q.1: Theoretically, when an ideal gas in a closed container cools, the pressure will drop steadily until the pressure inside is essentially that of a vacuum. At what temperature should this occur?
A: 0ºC
B: -460 ºC
C: -273 K
D: 0 K
Select the labelled statement that best fits your answer.

Q.2: If the attractive forces among solid particles are less than the attractive forces between the solid and a liquid, the solid will
A: probably form a new precipitate as its crystal lattice is broken and re-formed.
B: be unaffected because attractive forces within the crystal lattice are too strong for the dissolution to occur.
C: begin the process of melting to form a liquid.
D: dissolve as particles are pulled away from the crystal lattice by the liquid molecules
Select the labelled statement that best fits your answer.
Select the labelled statement that best fits your answer.
Select the option that best fits your answer.
Select the option that best fits your answer.

Q.3: If the solubility of NaCl at 25 ºC is 36.2 g/100 g H2O, what mass of NaCl can be dissolved in 50.0 g of H2O?
A: 18.1 g
B: 36.2 g
C: 72.4 g
D 86.2 g
Select the option that best fits your answer.

Q.4: How many moles of HNO3 are needed to prepare 5.0 liters of a 2.0 M solution of HNO3?
A: 2.5
B: 5
C: 10
D: 20
Select the option that best fits your answer.

Q.5: The Dead Sea is the saltiest sea in the world. It contains 332 grams of salt per 1000 grams of water. What is the concentration in parts per million (ppm)?
A: 0.332 ppm
B: 332 ppm
C: 33,200 ppm
D: 332,000 ppm
Select the option that best fits your answer.

Q.6: The random molecular motion of a substance is greatest when the substance is
A: condensed.
B: a liquid.
C: frozen.
D: a gas.
Select the option that best fits your answer.

Q.7: Which of these is an example of an exothermic chemical process?
A: evaporation of water
B: melting ice
C: photosynthesis of glucose
D: combustion of gasoline
Select the option that best fits your answer.

Q.8: The boiling point of liquid nitrogen is 77 kelvin. It is observed that ice forms at the opening of a container of liquid nitrogen. The best explanation for this observation is
A: water at zero degrees Celsius is colder than liquid nitrogen and freezes.
B: the nitrogen boils and then cools to form a solid at the opening of the container.
C: water trapped in the liquid nitrogen escapes and freezes.
D: the water vapor in the air over the opening of the liquid nitrogen freezes out.
Select the option that best fits your answer.

Q.9: The specific heat of copper is about 0.4 joules/gram ºC. How much heat is needed to change the temperature of a 30-gram sample of copper from 20.0 ºC to 60.0 ºC?
A: 1000 J
B: 720 J
C: 480 J
D: 240 J
Select the option that best fits your answer.

Q.10: Equal volumes of 1 molar hydrochloric acid (HCl) and 1 molar sodium hydroxide base (NaOH) are mixed. After mixing, the solution will be
A: strongly acidic.
B: weakly acidic.
C: nearly neutral.
D: weakly basic.
Select the option that best fits your answer.

Q.11: Which of the following is an observable property of many acids?
A: They become slippery when reacting with water.
B: They react with metals to release hydrogen gas.
C: They produce salts when mixed with other acids.
D: They become more acidic when mixed with a base.
Select the option that best fits your answer.

Q.12: Copper(II) nitrate and sodium hydroxide solutions react in a test tube as shown below:
Cu(NO3)2(aq) + 2NaOH(aq) = Cu(OH)2(s) + 2NaNO3(aq)
If nitric acid is added to the test tube, the amount of solid precipitate decreases. The best explanation for this is that the acid
A: dilutes the solution making the precipitate dissolve.
B: reacts with the copper (II) nitrate, pulling the equilibrium to the left.
C: will dissolve most solids, including sodium nitrate.
D: will react with the copper (II) hydroxide to form water and soluble copper (II) nitrate.
Select the option that best fits your answer.

Q.13: Potassium hydroxide (KOH) is a strong base because it
A: easily releases hydroxide ions.
B: does not dissolve in water.
C: reacts to form salt crystals in water.
D: does not conduct an electric current.
Select the option that best fits your answer.

Q.14: Of four different laboratory solutions, the solution with the highest acidity has a pH of
A: 11.
B: 7.
C: 5.
D: 3.
Select the option that best fits your answer.

Q.15: 2CO + O2 = 2CO2
If the above reaction takes place inside a sealed reaction chamber, then which of these procedures will cause a decrease in the rate of reaction?
A: raising the temperature of the reaction chamber
B: increasing the volume inside the reaction chamber
C: removing the CO2 as it is formed
D: adding more CO to the reaction chamber
Select the option that best fits your answer.

Q.16: A catalyst can speed up the rate of a given chemical reaction by
A: increasing the equilibrium constant in favor of products.
B: lowering the activation energy required for the reaction to occur.
C: raising the temperature at which the reaction occurs.
D: increasing the pressure of reactants, thus favoring products.
Select the option that best fits your answer.

Q.17: When a reaction is at equilibrium and more reactant is added, which of the following changes is the immediate result?
A: The reverse reaction rate remains the same.
B: The forward reaction rate increases.
C: The reverse reaction rate decreases.
D: The forward reaction rate remains the same
Select the option that best fits your answer.

Q.18: 4HCl(g) + O2(g) = 2H2O(l) + 2Cl2(g) + 113 kJ
Which action will drive the reaction to the right?
A: heating the equilibrium mixture
B: adding water to the system
C: decreasing the oxygen concentration
D: increasing the system’s pressure
Select the option that best fits your answer.

Q.19: A mass of 5.4 grams of aluminum (Al) reacts with an excess of copper(II) chloride (CuCl2 ) in solution, as shown below:
3CuCl2 + 2Al = 2AlCl3 + 3Cu
What mass of solid copper (Cu) is produced?
A: 0.65 g
B: 8.5 g
C: 13 g
D: 19 g
Select the option that best fits your answer.

Q.20: Fe2O3 + 3CO = 2Fe + 3CO2
In this reaction, how many grams of Fe2O3 are required to completely react with 84 grams of CO?
A: 64 g
B: 80 g
C: 160 g
D: 1400 g
Select the option that best fits your answer.

Q.21: How many moles of chlorine gas are contained in 9.02 ×1023 molecules?
A: 1.5 moles
B: 2.0 moles
C: 6.02 moles
D: 9.03 moles
Select the option that best fits your answer.

Q.22: How many moles of CH4 are contained in 96.0 grams of CH4?
A: 3.00 moles
B: 6.00 moles
C: 12.0 moles
D: 16.0 moles
Select the option that best fits your answer.

Q.23: In a sealed bottle that is half full of water, equilibrium will be attained when water molecules
A: cease to evaporate.
B: begin to condense.
C: are equal in number for both the liquid and the gas phase.
D: evaporate and condense at equal rates
Select the option that best fits your answer.

Q.24: C3H8 + O2 = CO2 + H2O
This chemical equation represents the combustion of propane. When correctly balanced, the coefficient for water is
A: 2.
B: 4.
C: 8.
D: 16.
Select the option that best fits your answer.

Q.25: How many moles of carbon-12 are contained in exactly 6 grams of carbon-12?
A: 0.5 mole
B: 2 moles
C: 3.01 × 1023 moles
D: 6.02 × 1023 moles
Select the option that best fits your answer.

Q.26: NO2(g) + CO(g) = NO(g) + CO2(g)
The reaction shown above occurs inside a closed flask. What action will shift the reaction to the left?
A: pumping CO gas into the closed flask
B: raising the total pressure inside the flask
C: increasing the NO concentration in the flask
D: venting some CO2 gas from the flask
Select the option that best fits your answer.




                     
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