Chemistry Chapter 12: Stoichiometry

Calculate many moles of Al2O3 are needed to produced when 0.60 mol of Fe is produced in the following reaction. 2Al(s) + 3FeO(s) --> 3Fe(s) + Al2O3(s) a. 0.20 mol b. 0.40 mol c. 0.60 mol d. 0.90 mol

a. 0.20 mol

Which conversion factor do you use first to calculate the number of grams of CO2 produced by the reaction of 50.6 g of CH4 with O2 ? The equation for the complete combustion of methane is: CH4 (g) + 2O2 (g) --> CO2 (g) + 2H2O(l) a. 1 mol CH4/16.0 g CH4 b. 2 mol O2/ 1 mol CO2 c. 16.0g CH4/1 mol CO4 d. 44.0g CO2/ 2 mol CO2

a. 1 mol CH4/16.0 g CH4

At STP, how many liters of oxygen are required to react completely with 3.6 liters of hydrogen to form water? 2H(2) (g) + O(2) (g) -->> 2H(2)O(g) a. 1.8 L b. 3.6 L c. 2.0 L d. 2.4 L

a. 1.8 L

How many grams of chromium are needed to react with an excess of CuSO4 to produce 27.0g Cu? 2Cr(s) + 3CuSO4(aq)---->Cr2(SO4)3(aq) + 3Cu(s)

a. 14.7 grams

Methane and hydrogen sulfide form when hydrogen reacts with carbon disulfide identify the excess reagent and calculate how much remains after 36 l of h2 reacts with 12 l of cs2 4 h2 g cs2 g ch4 g 2 h2s g

a. 3 L CS2

Which of the following would be the limiting reagent in the reaction shown below? 2H2(g) + O2(g) --> 2H2O(g)

a. 50 molecules of H2

Which of the following is true about the total number of reactants and the total number of products? C2H12(l) + 8O2 = 5Co2(g) + 6H2O(g) a. 9 moles of reactants chemically change into 11 moles of products b. 9 grams of reactants chemically change into 11 grams of products c. 9 liters of reactants chemically change into 11 grams of products d. 9 atoms of reactants chemically change into 11 atoms of products

a. 9 moles of reactants chemically change into 11 moles of products

Which statement is true if 12 mol CO and 12 mol Fe2O3 are allowed to react? 3CO (g) + Fe2O3 (s) ---> 2Fe (s) + 3CO2(g)

a. limiting reagent is CO and 8.0 mol Fe will be formed.

The calculation of quantities in chemical equations is called a. stoichiometry b. dimensional analysis c. percent composition d. percent yield

a. stoichiometry

How many liters of chlorine gas can be produced when 0.98 L of HCl react with excess O2 at STP? 4HCl(g) + O2(g) -- >2Cl2 (g) + 2H2O(g)

b. 0.49 L

How many moles of aluminum are needed to react completely with 1.2 mol of FeO? 2Al(s) + 3FeO(s) --> 3Fe(s) + Al2O3(s) a. 1.2 mol b. 0.8 mol c. 1.6 mol d. 2.4 mol

b. 0.8 mol

How many moles of H3PO are produced when 71g P4O10 reacts completely to form H3PO4? a. 0.635 mol b. 1.00 mol c. 4.00 mol d. 16.0 mol

b. 1 mol

Which of the following statements is true about the following reaction? 3NaHCO3(aq) + C6H8O7(aq) --> 3CO2(g) + 3H2O(s) +Na3C6H5O7(aq) a. 22.7 L of CO2 (g) are produced for every liter of C6H8O7 (aq) reacted b. 1 mole of water is produced for every mole of carbon dioxide produced c. 6.02 x 10^23 molecules of Na3C6H5O7 (aq) are produced for every NaHCO3 (aq) used d. 54 g of water are produced for every mole of NaHCO3 (aq) produced

b. 1 mole of water is produced for every mole of carbon dioxide produced

How many moles of glucose, C6H12O6, can be "burned" biologically when 10.0 mol of oxygen is available? C6H12O6 (s) + 6O2 (g) --> 6CO2 (g) + 6H2O(l) a. 0.938 mol b. 1.67 mol c. 53.3 mol d. 60.0 mol

b. 1.67 mole of glucose

When iron rusts in air, iron(III) oxide is produced. How many moles of oxygen react with 2.4 mol of iron in the rusting reaction? 4Fe(s) + 3O2(g) --> 2Fe2O3(s) a. 1.2 mol b. 1.8 mol c. 2.4 mol d. 3.2 mol

b. 1.8 mol

Metallic copper is formed when aluminum reacts with copper(II) sulfate. How many grams of metallic copper can be obtained when 54.0 g of Al react with 319 g of CuSO4 ? Al + 3CuSO4--> Al2 (SO4 )3+ 3Cu

b. 127 g

Which of the following is an INCORRECT interpretation of the balanced equation shown below? 2S(s) + 3O2(g) -->2SO3(g) a. 2 atoms S + 3 molecules O2 --> 2 molecules of SO3 b. 2 g S + 3 g O2 --> 2 g SO3 c. 2 mol S + 3 mol O2 --> 2 mol SO3 d. 5 mol of reactants --> 2 mol of products

b. 2 g S + 3 g O2--> 2 g SO3

The equation below shows the decomposition of lead nitrate. How many grams of oxygen are produced when 11.5 g NO2 is formed? 2Pb(NO3) 2(s) --> 2PbO(s) + 4NO2 (g) + O2(g) a. 1.00 g b. 2.00 g c. 2.88 g d. 32.0 g

b. 2.00 g

How many liters of NH3, at STP, will react with 5.3g of 02 to form NO2 and water.?

b. 2.12 liters of NH3

How many liters of NH3 are needed to react completely with 30.0 L of NO (at STP)? 4HN3(g) + 6NO(g) ----> 5H2(g) +6H2O(g) a. 5.0 L b. 20.0 L c. 7.5 L d. 120.0 L

b. 20.0 L

Iron(III) oxide is formed when iron combines with oxygen in the air. How many grams of Fe2O3 are formed when 16.7 g of Fe reacts completely with oxygen? 4Fe(s) + 3O2(g) --> 2Fe2O3(s) a. 12.0 g b. 23.9 g c. 47.8 g d. 95.6 g

b. 23.9g

Aluminum reacts with sulfuric acid to produce aluminum sulfate and hydrogen gas. How many grams of aluminum sulfate would be formed if 250 g H2SO4 completely reacted with aluminum? 2AL(s) + 3H2SO4 (aq) --> Al2 (SO4)3 (aq) + 3H2 (g) a. 0.85 g b. 290 g c. 450 g d. 870 g

b. 290 g

What is the maximum number of grams of PH3 that can be formed when 6.2 g of phosphorus reacts with 4.0 g of hydrogen to form PH3 ? P4 (g) + 6H2(g) --> 4PH3 (g)

b. 6.8 g

Calcium oxide, or lime, is produced by the thermal decomposition of limestone in the reaction CaCO3 (s) --> CaO(s) + CO2(g). What mass of lime can be produced from 1.5 x 10^3 kg of limestone? a. 8.4 x 10^5 kg b. 8.4 x 10^2 kg c. 8.4 kg d. none of the above

b. 8.4 x10^2 kg

When 0.1 mol of calcium reacts with 880 g of water, 2.24 L of hydrogen gas form (at STP). How would the amount of hydrogen produced change if the volume of water was decreased to 440 mL (440 g)? a. Only one half the volume of hydrogen would be produced b. The volume of hydrogen produced would be the same c. The volume of hydrogen produced would double d. No hydrogen would be produced

b. The volume of hydrogen produced would be the same.

What is the first step in most stoichiometry problems? a. add the coefficients of the reagents b. convert given quantities to mole c. convert given quantities to volumes d. convert given quantities to masses

b. convert given quantities to mole

When two substances react to form products, the reactant used up is called what? a. determining reagent b. limiting reagent c. excess reagent d. catalytic reagent

b. limiting reagent

Mercury can be obtained by reacting mercury(II) sulfide with calcium oxide. How many grams of calcium oxide are needed to produce 36.0 g of Hg? 4HgS(s) + 4CaO(s) -->4Hg(l) + 3CaS(s) + CaSO4 a. 1.80 g b. 7.56 g c. 10.1 g d. 13.4 g

c. 10.1 g

. How many grams of beryllium are needed to produce 36.0 g of hydrogen? (Assume an excess of water.) Be(s) + 2H2O(l) --> Be(OH)2 (aq) + H2(g)

c. 162 g

In the reaction 2CO(g)+O2(g)-->2CO2(g) what is the raito of the moles of oxygen used to moles of CO2 produced? a. 1:1 b. 2:1 c. 1:2 d. 2:2

c. 1:2

If 1 egg and 1/3 cup of oil are needed for each bag of brownie mix, how many bags of brownie mix do you need if you want to use up all 3 eggs and 1 cup of oil? a. 1 b. 2 c. 3 d. 4

c. 3

In a particular reaction between copper metal and silver nitrate, 12.7 g Cu produced 38.1 g Ag. What is the percent yield of silver in this reaction? Cu + 2AgNO3--> Cu(NO3) 2 + 2Ag

c. 88.2%

In a chemical reaction, the mass of the products is? a. is less than the mass of the reactants b. is greater than the mass of reactants c. is equal to the mass of the reactants d. has no relationship to the mass of the reactants

c. is equal to the mass of the reactants

Which of the following are conserved in every chemical reaction? a. mass and molecules b. moles and liters c. mass and atoms d. moles and molecules

c. mass and atoms

What is conserved in the reaction shown below?N2(g)+3F2(g)__2NF3(g) a. atoms only b. mass only c. mass and atoms only d. moles only

c. mass and atoms only

In any chemical reaction, what quantities are always preserved? a. the number of moles and the volumes b. the number of molecules and the volumes c. mass and number of atoms d. mass and moles

c. mass and number of atoms

When an equation is used to calculate the amount of product that will form during a reaction then the value obtained is called the what?

c. theoretical yield

How many liters of hydrogen gas are needed to react with CS2 to produce 2.50 L of CH4 at STP? 4H2(g)+CS2(l) = CH4(g) +2H2S(g) a. 2.50 L b. 5.00 L c. 7.50 L d. 10.0

d. 10.0 L

Hydrogen gas can be produced by reacting aluminum with sulfuric acid. How many moles of sulfuric acid are needed to completely react with 15.0 mol of aluminum? 2Al(s) + 3H2SO4 (aq) --> Al2 (SO4 )3 (aq) + 3H2(g) a. 0.100 mol b. 10.0 mol c. 15.0 mol d. 22.5 mol

d. 22.5 mol

Hydrogen gas is produced when zinc reacts with hydrochloric acid. If the actual yield of this reaction is 85%? how many grams of zinc are needed to produce 112 l of H2 at STP?

d. 380

How many grams of H3PO4 are produced when 10.0 moles of water react with an excess of P4O10 ? P4O10 (s) + 6H2O(l) --> 4H3PO4 (aq) a. 1.22 g b. 6.7 g c. 147 g d. 653 g

d. 653 g

When glucose is consumed, it reacts with oxygen in the body to produce carbon dioxide, water, and energy. How many grams of carbon dioxide would be produced if 45 g of C6H12O6 completely reacted with oxygen? a. 1.5 g b. 1.8 g c. 11 g d. 66 g

d. 66 g

Lead nitrate can be decomposed by heating. What is the percent yield of the decomposition reaction if 9.9 g Pb(NO3 )2 are heated to give 5.5 g of PbO? 2Pb(NO3 )2(s) -->2PbO(s) + 4NO2(g) + O2 (g)

d. 82%

Glucose, C6H12O6, is a good source of food energy. When it reacts with oxygen, carbon dioxide and water are formed.How many liters of CO2 are produced when 126 grams of glucose completely react with oxygen? C6H12O6 (s) + 6 O2 --> 6 CO2 (g) + 6 H2O (l) = 673 kcal a. 4.21 L b. 5.33 L c. 15.7 L d. 94.1 L

d. 94.1 L

Which of the following is NOT true about "yield"?

d. The actual yield may be different from the theoretical yield because reactions do not always go to completion.

Which of the following is NOT true about limiting and excess reagents?

d. The reactant that has the smallest given mass is the limiting reagent.

Which of the following is NOT a reason why actual yield is less than theoretical yield?

d. conservation of mass

What is conserved in the reaction shown below? H2(g) + Cl2 (g) --> 2HCl(g) a. mass only b. mass and moles only c. mass, moles, and molecules only d. mass, moles, molecules, and volume

d. mass, moles, molecules, and volume

Which type of stoichiometric calculation does NOT require the use of the molar mass? a. mass-mass problems b. mass-volume problems c. mass-particle problems d. volume-volume problems

d. volume-volume problems