Exam 3
Hydrogen gas reacts with oxygen to form water, 2 H2 + O2 2 H2O. If you want to convert moles of O2 to moles of water, what mole ratio do you use?
a. (2 moles H2/1 mole O2) b. (1 mole O2/2 moles H2O) >>c. (2 moles H2O/1 mole O2) d. (1 mole H2O/1 mole O2)
What is the equilibrium constant expression for the reaction 2 POCl3 ↔ 2 PCl3 + O2?
a. ([PCl3][O2])/[POCl3] b. ([PCl3]2+[O2])/[POCl3]2 >>c. ([PCl3]2[O2])/[POCl3]2 d. [POCl3]2/([PCl3]2[O2])
What is the oxidation number of carbon in CO2?
a. 0 >>b. +4 c. +2 d. -4
If I add 5.00 grams of sucrose (C12H22O11) to my cup of coffee, how many moles of sucrose did I add?
a. 0.172 mol >>b. 0.0146 mol c. 68.4 mol d. 1710 mol
What is the molecular weight of Ca(NO3)2?
a. 102.1 g/mol >>b. 164.1 g/mol c. 204.2 g/mol d. 120.4 g/mol
What is the molecular weight of iodine pentafluoride?
a. 145.9 g/mol b. 653.5 g/mol >>c. 221.9 g/mol d. 1241.9 g/mol
Suppose 10.0 g of CH4 is used in a reaction that can theoretically produce 95.8 g of CCl4. What is the percent yield of CCl4 if the reaction produced only 80.0 g of CCl4?
a. 15.8% b. 120% >>c. 83.5% d. 80%
. Propane (C3H8) burns in oxygen to form carbon dioxide and water. What is the balanced chemical equation for this reaction?
a. 2 C3H8 + 9 O2 6 CO2 + 6 H2O b. C3H8 + O2 CO2 + H2O >>>c. C3H8 + 5 O2 3 CO2 + 4 H2O d. C3H8 + 3 O2 5 CO2 + 4 H2O
Which of the following is an endothermic reaction?
a. 2 SO2 + O2 2 SO3 H = -47 kcal/mole >>b. The enthalpy of the reactants is less than the enthalpy of the products. c. CH4 + 2 O2 CO2 + 2 H2O + 213 kcal d. None of the above
Natural gas (CH4) burns in oxygen to form carbon dioxide and water, as shown below. How many moles of carbon dioxide are produced from 3.8 moles of oxygen? CH4 + 2 O2 2 H2O + CO2
a. 3.8 moles b. 2 moles c. 7.6 moles >>d. 1.9 moles
If 3.0 moles of gaseous SO2 react with oxygen to produce sulfur trioxide, how many mole of oxygen are needed?
a. 6.0 moles O2 b. 4.0 moles O2 >>c. 1.50 moles O2 d. 3.0 moles O2
When you metabolize 50.0 grams of sucrose (C12H22O11), how many grams of CO2 are produced? C12H22O11 + 12 O2 11 H2O + 12 CO2
a. 6.43 g b. 600 g >>c. 77.2 g d. 0.536 g
What are the spectator ions in the reaction AgNO3(aq) + NaCl(aq) AgCl(s) + NaNO3(aq)?
a. Ag+ and NO3- b. Na+ and Cl- c. Ag+ and Cl- >>d. Na+ and NO3-
Which of the following is the net ionic equation for the reaction of barium nitrate with calcium sulfate?
a. Ba(NO3)2(aq) + CaSO4(aq) BaSO4(s) + Ca(NO3)2(aq) b. Ba2+(aq) + 2 NO3-(aq) + Ca2+(aq) + SO42-(aq) BaSO4(s) + Ca2+(aq) + 2 NO32-(aq) >>c. Ba2+(aq) + SO42-(aq) BaSO4(s) d. Ca2+(aq) + 2 NO32-(aq) Ca(NO3)2(aq)
Which of the following is not true of the reaction N2(g) + 3 H2(g) ↔ 3 NH3(g) + heat?
a. Heating the reaction will shift the reaction to the left. b. An increase in pressure will shift the reaction to the right. c. Removal of ammonia will shift the reaction to the right. >>d. Addition of a catalyst will shift the reaction to the right.
What precipitate is formed in the reaction of aqueous Pb(NO3)2 with aqueous KI?
a. KNO3 b. PbI c. KI >>d. PbI2
In which of the following cases does entropy increase?
a. Liquid water freezes and becomes ice. b. Cl2(g) + H2C=CH2(g) ClCH2CH2Cl(l) c. N2(g) + 3 H2(g) 2 NH3 (g) >>d. H2O(l) H2O(g)
For the following reaction, which reactant is reduced? Mg + Cu2+(aq) Mg2+(aq) + Cu
a. Mg >>b. Cu2+ c. Mg2+ d. Cu
What happens when oxidation occurs?
a. Oxygen is gained, hydrogen is gained, or electrons are gained. b. Oxygen is lost, hydrogen is lost, or electrons are gained. c. Oxygen is lost, hydrogen is lost, or electrons are lost. >>d. Oxygen is gained, hydrogen is lost, or electrons are lost.
Which of the following objects has mainly kinetic energy?
a. a flashlight >>b. a baseball that has just been pitched c. a book sitting on the edge of a shelf d. a sandwich
What happens to the activation energy of a reaction when a catalyst is added?
a. activation energy is increased >>b. activation energy is decreased c. there is no change in activation energy d. it depends on whether the reaction is endothermic or exothermic.
Which of the following will not increase the rate of the reaction A + B C?
a. addition of a catalyst b. increasing concentrations of A and B >>c. decreasing the temperature d. all of these will increase the rate of reaction
In an acid-base neutralization, what is the origin of the cation in the product salt?
a. cation from the acid b. anion from the acid >>>c. cation from the base d. anion from the base
Which three factors affect the rate of reaction?
a. temperature, volume, and concentration b. temperature, pressure, and concentration >>c. temperature, catalyst, and concentration d. temperature, catalyst, and humidity
How many moles of Pb(C2H3O2)2 are in 25.4 grams of Pb(C2H3O2)2?
>>a. 0.0781 mol b. 0.0536 mol c. 8.26 x 103 mol d. 12.8 mol
Which of the following is an oxidation-reduction reaction?
>>a. 2 Al(s) + 3 Br2 → 2 AlBr3(s) b. Ca(OH)2(aq) + 2 HNO3(aq) → 2 H2O(l) + Ca(NO3)2(aq) c. Ag (NO3)(aq) + KCl(aq) → AgCl(s) + KNO3(aq) d. None of the above
Which of the following is a precipitation reaction?
>>a. BaCl2(aq) + Na2SO4(aq) BaSO4(s) + 2 NaCl(aq) b. NaOH + HCl H2O + NaCl c. NH3 + HCl NH4Cl d. 2 Na + Cl2 2 NaCl
Which of the following statements describes an endothermic reaction?
>>a. Energy is absorbed. b. Energy is released. c. Energy is conserved. d. Energy is not involved in the reaction
If 5.0 gram of H2 reacts with 42 g of O2 according to the reaction 2 H2 + O2 2 H2O, what is the limiting reactant?
>>a. H2 b. O2 c. H2O d. both H2 and O2
Which of the following favors a spontaneous process?
>>a. increasing entropy b. decreasing entropy c. decreasing enthalpy d. none of the above
For a particular reaction, K = 1.6 x 10-5. Does the equilibrium for this reaction favor the reactants or the products?
>>a. reactants b. products c. neither d. both
Which weighs larger?
>>a. two moles of H2O b. 30 grams of SiO2 c. two mole of boron d. 0.5 moles of calcium
What are the products of an acid-base neutralization reaction?
>>a. water and a salt b. water and a precipitate c. a different acid-base pair d. carbon dioxide and water
