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6. Balance the following equations (Note: the exercises cannot be done until the topics of naming and formula writing of compounds have been learned.)
a. iron(III) hydroxide + sulfuric acid iron(III) sulfate + water
2Fe(OH)3 + 3H2SO4 Fe2(SO4)3 + 6H2O
b. calcium carbonate + nitric acid calcium nitrate + water + carbon
dioxide
CaCO3 + 2HNO3 Ca(NO3)2 + H2O + CO2
c. phosphoric acid + sodium hydroxide sodium phosphate + water
H3PO4 + 3NaOH Na3PO4 + 3H2
d. silver nitrate + cupric chloride barium carbonate + ammonium nitrate
2Ag NO3 + CuCl2 2AgCl + Cu(NO3)
e. barium nitrate + ammonium carbonate
barium carbonate + ammonium nitrate
Ba(NO3)2 + (NH4)2CO3 BaCO3 + 2NH4NO3
f. lead(II) chloride + nitric acid lead(II) nitrate + hydrogen chloride
PbCl2 + 2HNO3 Pb(NO3)2 + 2HCl
g. magnesium chloride + ammonium carbonate ammonium chloride + magnesium carbonate
MgCl2 + (NH4)2CO3 2NH4Cl + MgCO3
h. mercurous nitrate + sodium chloride mercurous chloride + sodium nitrate
Hg2(NO3)2 + 2NaCl Hg2Cl2 + 2NaNO3
i. barium nitrate + sodium hydroxide barium hydroxide + sodium nitrate
Ba(NO3)2 + 2NaOH Ba(OH)2 + 2NaNO3
j. iron + sulfur ferrous sulfide Fe + S FeS
k. aluminum + nitric acid aluminum nitrate + hydrogen
2(Al + 3HNO3 Al(NO3)3 + (3/2)H2)2Al + 6HNO3 2Al(NO3)3 + 3H2
l. calcium oxide + hydrochloric acid calcium oxide + hydrochloric
acid
CaO + 2HCl CaCl2 + H2
m. stannic nitrate + potassium sulfate stannic sulfate + potassium nitrate
Sn(NO3)4 + 2K2SO4 Sn (SO4)2 + 4KNO3
n. mercurous oxide mercury +oxygen
2(Hg2O Hg + (1/2)O2) 2Hg2O 2Hg + O2
o. lithium chloride + plumbous nitrate plumbous chloride +lithium nitrate
2LiCl + Pb(NO3)2 PbCl2 + 2LiNO3
p. calcium + aluminum chloride calcium chloride + aluminum
3Ca + 2AlCl3 3CaCl2 + 2Al
q. nitric acid + aluminum hydroxide aluminum nitrate + water
3HNO3 + Al(OH)3 Al(NO3)3 + 3H2O
23. 6.75g of aluminum is reacted with excess H2SO4. (a) Find the volume of H2 produced at STP. (b) What volume is this at 880mm and 27°C?
2Al(s) + 3H2SO4(aq) → Al2(SO4)3(aq) + 3H2(g)
(a) moles Al = 6.75g/27g/mole = 0.25mole moles H2 = (0.25 molesAl)(3 moles H2/2 moles Al) = 0.375 mole VH2 @ STP = (0.375 moles)(22.4 liters/mole) = 8.4 liters
(b) P1V1/T1 = P2V2/T2
V2 = (P1)(V1)(T2)/(P2)(T1) = (760mm)(8.4 liters)(27+273°K) = 7.95 liters (880mm)(273°K)
1. Find the density of a peice of wood measuring 2cm x 1.5cm x 1cm and weighing 2.8g.
V = L x W x H = 2cm x 1.5cm x 1cm = 3cm3
D = M/V = 2.8g / 3cm3 = 0.93 g/cm3
2. Will the wood in question 1 float on fresh water? (Density of fresh water = 1.00 g/ml)
Since Dwood < DH2O, the wood floats!Dwood = .93 g/cm3
DH2O = 1.00 g/ml or 1.00 g/cm3
3. Find the density of a piece of lead measuring 5cm x 30mm x 20mm and weighing 336g.
30mm = 3cm and 20mm = 2cm V = 5cm x 3cm x 2cm = 30cm3
D = M/V = 336g/30cm3 = 11.2 g/cm3
4. Find the density of a sugar solution having a 15g mass and a 13.5ml volume.
D = M/V = 15g/13.5ml = 1.11 g/ml
5. 100,000ml of a gas weighs .02g. Find the density of the gas.
100,00 ml = 100D = g/ = .02g/100 = 0.0002 g/
6. A solid aluminum cylinder has a diameter of 3.0cm and a height of 6cm. The cylinder weighs 114.5g. Find the density. (i.e. V = pr2h for cylinders.)
V = pr2h = (3.14)(3cm/2)2 (6cm) = 42.39cm3
D = M/V = 114.5g/42.39cm3 = 2.7 g/cm3
7. What is the mass of a piece of metal which has a density of 6 g/cm3 and a volume of 8cm3?
D = M/VM = DV = (6 g/cm3)(8cm3) = 48g
8. What is the volume of a solution which has a density of 1.2 g/ml and a
mass of 5g?
D = M/V
9. 10gof H2O at 4°C has a 10ml volume while the same weight of H2O at 98°C has a volume of 10.05ml.
a. Calculate the density of H2O at the 2 temperatures.
4°C:D 4°C = 10g/10ml = 1.00 g/ml
98°C:D 98°C = 10g/10.05ml = 0.995 g/ml
b. State a general relationship between temperatures, volume, and density.
When a substance is heated, it expands (V ). Since mass is unchanged, the fraction M/V decreases (or D decreases).
10. A rock has a 3.2 g/cm3 density and weighs 20g. What is the rock’s volume?
D = M/V
18. Fill out the table below:
Element Ion Ion Name (Give two)
IronFe2+ Ferrous, Iron(II)Fe3+ Ferric, Iron(III)
MercuryHg2
2+ Mercurous, Mercury(I)Hg2+ Mercuric, Mercury(II)
TinSn2+ Stannous, Tin(II)Sn4+ Stannic, Tin(IV)
LeadPb2+ Plumbous, Lead(II)Pb4+ Plumbic, Lead(IV)
CopperCu1+ Cuprous, Copper(I)Cu2+ Cupric, Copper(II)
4. Find the # oxygen atoms present in 20g of each of the following
# moles CO = = = .71 moles
1 mole CO 1 mole C and 1 mole O.71 moles CO .71 moles O
# O atoms = (.71 moles)(6 x 1023 atoms/mole)= 4.26 x 1023 atoms
MW CO2 = = 44g/mole
# moles CO2 = = .45 moles
1 mole CO2 1 mole C atoms and 2 moles O atoms.45 Moles CO2 2(.45 moles) = .90 moles O atoms
# O atoms = (.90 moles)(6 x 1023 atoms/mole)= 5.4 x 1023 atoms
MW H2O = 2(1g) + 1(16g) = 18g/mole
# moles H2O = = 1.1 moles
1 mole H2O 2 moles H atoms and 1 mole O atoms1.1 moles H2O 1.1 moles O atoms
# O atoms = (1.1 moles)(6 x 1023 atoms/mole)= 6.6 x 1023 atoms
MW Al2(SO4)3 == 54g + 96g + 192g = 342g/mole
Moles Al2(SO4)3 = = .059 moles
1 mole Al2(SO4)3 12 moles O atoms
.059 moles Al2(SO4)3 (12 moles)(.059 moles)= .70 moles O
# O atoms = (.70 moles)(6 x 1023 atoms/mole)= 4.2 x 1023 atoms
5. 320g of Bromine molecules contains how many…
a) molecules?MW Br2 = 2(80g) = 160g/mole
# moles Br2 = 2 moles
# Br2 molecules= (2 moles)(6 x 1023 molecules/mole)= 12 x 1023 molecules = 1.2 x 1024 molecules
b) atoms?1 mole Br2 molecules 2 moles Br atoms
# Br atoms = (2 atoms/mole)(1.2 x 1024 molecule)= 2.4 x 1024 atoms
6. Find the # of each atom present in a 77.5g sample of Ca3(PO4)2.
MW Ca3(PO4)2 = = 120g + 62g + 128g = 310g/mole
# moles Ca3(PO4)2 = = .25 moles
1 mole Ca3(PO4)2 3 moles Ca atoms, 2 moles P atoms and 8 moles O atoms
.25 moles Ca3(PO4)2 3(.25) = .75 moles Ca, 2(.25) = .5 moles P,and 8(.25) = 2 moles O
# Ca atoms = (.75 moles)(6 x 1023 atoms/mole) = 4.5 x 1023 atoms# P atoms = (.5 moles)(6 x 1023 atoms/mole) = 3 x 1023 atoms# O atoms = (2 moles)(6 x 1023 atoms/mole) = 12 x 1023 = 1.2 x 1024 atoms
7. Find the grams of each atom present in the sample of Ca3(PO4)2 from question 6.
#g Ca = (.75 moles)(40g/mole) = 30g Ca#g P = (.5 moles)(31g/mole) = 15.5g P#g O = (2 moles)(16g/mole) = 32g O
8.a) Find the # nitrogen and oxygen atoms present in a 23g sample of N2O4.
MW N2O4 = = 28g + 64g = 92 g/mole
# moles N2O4 = = .25 mole
1 mole N2O4 2 moles N and 4 moles O
.25 moles N2O4 2(.25) = .5 moles N and 4(.25) = 1 mole O
# N atoms = (.5 moles)(6 x 1023 atoms/mole) = 3 x 1023 N atoms# O atoms = (1 mole)(6 x 1023 atoms/mole) = 6 x 1023 O atoms
8.b) Find the #g of each atom.
#g N = (.5 moles)(14 g/mole) = 7g N#g O = (1 mole)(16 g/mole) = 16g O
9.a) Find the # oxygen atoms in 284g of P2O5.
MW P2O5 = = 62g + 80g = 142 g/mole
# moles P2O5 = = 2 moles
1 mole P2O5 5 moles O2 moles P2O5 2(5 moles O) = 10 moles O
# O atoms = (10 moles)(6 x 1023 atoms/mole)= 60 x 1023 atoms = 6 x 1024 atoms
13. Find the molecular weight of…
Molecular Weight (MW) = #g/# moles
a) A molecule for which 3 moles weigh 180g.
MW = 180g/3 moles = 60 g/mole
b) A molecule for which 0.5 moles weigh 150g.
MW = 150g/.5 moles = 300 g/mole
c) A molecule for which 2 moles weigh 80g.
MW = 80g/2 moles = 40 g/mole
14. Consider the reaction C + O2 CO2. If 6g of carbon are used…
a) How many moles of carbon is this? # moles C = = .5 moles
b) How many carbon atoms is this? # C atoms= (.5 moles)(6 x 1023 atoms/mole)= 3 x 1023 atoms
c) How many moles of O2 molecules would be needed to react with the 6g of carbon?
Same # moles… .5 moles(See the reaction)
d) How many molecules of O2 is this?
(.5 mole)(6 x 1023 molecules/mole)= 3 x 1023 O2 molecules
e) How many atoms of O is this? # O atoms = 2(3 x 1023 atoms)= 6 x 1023 atoms
f) How many moles of CO2 are formed?
C + O2 CO2
.5 moles + .5 moles .5 moles
g) How many molecules of CO2 is this?
# CO2 molecules = (.5 moles)(6 x 1023) = 3 x 1023 molecules
h) How many grams of CO2 form? MW CO2 = 44 g/mole#g CO2 = (.5 moles)(44 g/mole)= 22g
Molar Volume of a Gas
1. Calculate the number of moles of each gas that are present for each. Give volume at STP.
a) 8 liters of N2
x = = .36 moles
b) 134.4 liters of H2
x = = 6 moles
c) 5.6 liters of CO
x = = .25 moles
d) 67.2 liters of N2O4
x = = 3 moles
e) 89,600ml of NO2 89,600ml= 89.6
x = = 4 moles
2. Find the number of molecules present in exercises 1 a), b), and c).
a) N2 # N2 molecules = (.36 moles)(6 x 1023 molecules/mole)= 2.16 x 1023 molecules
b) H2 # H2 molecules = (6 moles)(6 x 1023 molecules/mole)= 36 x 1023 molecules = 3.6 x 1024 molecules
c) CO # CO molecules = (.25 moles)(6 x 1023 molecules/mole)= 1.5 x 1023 molecules
3. Four moles of N2O5 gas will occupy what volume at STP.
x = = 89.6
4. 1.5 moles of NH3 gas will occupy what volume at STP.
x = = 33.6
5. How many grams of Cl2 gas are present in 11.2 liters of gas at STP?
x = = .5 molesMW Cl2 = 2(35.5) = 71 g/mole#g Cl2 = (MW)(moles) = (71 g/mole)(.5 moles) = 35.5g
6. How many grams of NH3 gas are present in 44.8 liters of the gas at STP?
x = = 2 molesMW NH3 = 14 + 3(1) = 17 g/mole#g NH3= (MW)(moles) = (17 g/mole)(2 moles) = 34g
7. 2.5g of a gas occupies 4 liters at STP. Find the molecular weight of the gas.
x = = 14g = MW
8. 1.25g of a gas occupies 2.5 liters at STP. Find the molecular weight of the gas.
x = = 11.2g = MW
9. A gas has a density of 1.75g/l at STP. Find its molecular weight.
x = = 39.2g = MW
10. A gas has a density of 2.75g/l at STP. Find its molecular weight.
x = = 61.6g = MW
11. Calculate the density of the following gases at STP:
a) SO2MW SO2 = = 64 g/mole1 mole = 22.4D = 64g/22.4 = 2.9 g/
b) O3MW = O3 = = 48 g/moleD = 48g/22.4 = 2.1 g/
c) PCl5MW PCl5 = = 208.5 g/moleD = 208.5g/22.4 = 9.3 g/
12. Calculate the volume (in liters and milliliters) occupied by each of the following gases at STP:
a) 14g of N2 MW N2 = 2(14) = 28 g/mole
x = x = 11.2 = 11,200ml
b) 528g of UF6MW UF6 = = 352 g/mole
x = x = 33.6 = 33,600ml
c) 90g of H2OMW H2O = = 18 g/mole
x = x = 112 = 112,000ml
Percent Composition Problems
1. Find the percent composition of the following compounds:
a. KBrAtomic Weights: K=39 Br=80
MW: 39 + 80 = 119g/mole
%K = (39/119) x 100 = 32.8%
%Br = (80/119) 100 = 67.2%
b. MgCO3
Atomic Weights: Mg=24 C=12 O=16
MW: 24 + 12 + 3(36) = 84g/mole
%Mg = (24/84) x 100 = 26.8%
%C = (12/84) x 100 = 14.3%
%O = (48/84 ) x 100 = 57.1%
c. Ca3(PO4)2
Atomic Weights: Ca=40 P=31 O=16
MW: 3(40) + 2(31) + 8(16) = 310g/moles
%C = (120/310) x 100 = 38.7%
%P = (62/310) x 100 = 20%
%O = (128/310) x 100 = 41. 3%
d. CO2
Atomic Weights: C=12 O=16
MW =12 + 2(16) = 44g/moles
%C = (12/44) x 100 = 27.3%
%O = (32/44 )x100 = 72.7%
e. COAtomic Weight: C=12 O=16
MW: 12 + 16 = 32g/mole
%C = (12/28) x 100 = 42.9%
%0 = (16/28 ) x 100 = 57.1%
f. C11H22O11
Atomic Weights: C=12 H=1 O=16
MW: 11(12) + 22(1) + 11(16) = 330g/mo.
%C = (132/330) x 100 = 40%
%H = (22/330) x 100 = 6.7%
%O = (176/330) x 100 = 53.3%
2. Find the percent H2O in each hydrate:
a. CaSO4× 2H2OAtomic Weights: Ca=40 S=32 O=16 H2O=18
MW: 40 + 32 + 4(16) + 218) = 172g/mole
%H2O = (36/127) x 100 = 20.9%
b. NiSO4× 6H2OAtomic Weights: Ni=59 S=32 O=16 H2O=18
MW: 59 + 32 + 4(16) + 6(18) = 263g/mole
%H2O = (108/263) x 100 = 41.0%
c. Na2SO4× 10H2OAtomic Weights: Na=23 S=32 O=16 H2O=18
MW: 2(23) + 32 + 4(16) + 10(18) = 322g/mole
%H2O = (180/322) x 100 = 55.9%
3. Find the percent of each element in CaCl2.2H2O.
Atomic Weights: Ca=40 Cl=35.5 H=1 O=16
MW: 40 + 2(35.5) + 4(1) + 2(16) = 147g/mole
%Ca = (40/147) x 100 = 27.2%
%Cl = (71/147) x 100 = 48.3%
% H = (4/147 ) x 100 = 2.7%
%O = (32/147)x100 = 21.8%
4. Find the percent oxygen in Na2SO4× 10H2O.
Atomic Weights: Na=23 S=32 O=16 H=1
MW: 2(23) + 1(32) + 14(16) + 20(1) = 322g/m
%O = ((14 x 16)/322) x 100 = (224/322) x 100 =
69.6%
5. A 10g sample of CO2 contains (a) how many grams of oxygen? (b) how many oxygen atoms? Use the percent composition of CO2 to solve this problem.
a. Find grams of oxygen:Atomic Weights: C=12 O=16
MW: 12 + 2(16) = 44g/mole
%O = ((2 x 16)/44) x 100 = (32/44) x 100 = 72.7%
gO = 10g x .727 = 72.7gO
b. Find number of oxygen atoms:
moles of O = (7.27/16g per mole) = 0.45 moles atoms = (.45 mole) x (6 x 1023 atoms per mole) = 2.7 x 1023 atoms
6. A 90g sample of glucose (C6H12O6) contains how many grams of oxygen?
Atomic weights: C=12 H=1 O=16
MW: = 6(12) + 12(1) + 6(16) = 180g/mole
%O = ((6 x 16)/180) x 100 = 53.34%
gO = (.533) x 90g = 48gO
Empirical & Molecular Formulas
1. Find empirical formulas for the compounds containing the following percentages of each element. Use these atomic weights: Li=7 Br=80 K=39 S=32 Mg=24 C=12 O=16 Ca=40 Sc=45
In all problems in which percentages of each element are given, because all the percentages of the elements in a compound add up to 100%, simply assume a 100g sample, then the weight of each element is the same as the percent. Calculate the moles of each element as: moles = grams/atomic weight.
a. 8.04 percent lithium, 91.96 percent bromide
b. 70.9 percent potassium, 29.1 percent sulfur
c. 28.6 percent magnesium, 14.3 percent carbon, 57.1 percent oxygen
d. 29.4 percent calcium, 23.5 percent sulfur, 47.1 percent oxygen
e. 65.2 percent scandium, 34.8 percent oxygen
f. 42.9 percent carbon, 57.1 percent oxygen
2. A 20g sample of a hydrate of nickel sulfate (NiSO4) lost 9.63g of water when heated. Determine the hydrate’s formula.
3. A hydrate containing copper, sulfur, oxygen, and water lost 9g upon heating. Originally the hydrate had weighed 25g. Analysis of the anhydrous substance revealed that the 6.4g of Cu, 3.2g of S, and 6.4g of O were present. Find the formula of the hydrate.
4. When heated in the presence of oxygen, 12g of the magnesium forms and oxide weighing 20g. Find the empirical formula of the oxide formed.
5. A sample of gas occupies 2.0 liters at STP. The sample contains 2.143g of carbon and 0.358g of hydrogen. Find the empirical and molecular formulas of the gas.
6. A compound was found to contain 55.2 percent xenon and 44.8 percent chlorine. Find the empirical formula.
7. Find the empirical and molecular formulas for the compounds given below. Atomic weights: C=12 H=1 O=16 N=14 Cl=35.5
a. 51.28 percent C, 9.40 percent H, 27.35 percent O, 11.97 percent N, MW=234
b. 33.18 percent C, 4.60 percent H, 29.49 percent O, 32.72 percent Cl, MW=108.5
c. 45.71 percent C, 10.48 percent H, 30.48 percent O, 13.3 percent N, MW=210
d. 40.00 percent C, 6.67 percent H, 53.33 percent O, MW=330
8. A 10g sample of a compound contains 4.00g C, 0.667g H, and 5.33g O. Find the empirical and molecular formulas. The MW is 180 amu.
Chemical Equations
Balance the following equations:
1. Combination
a. C + O2 CO2 C + O2 CO2
b. H2 + Cl2 HCl H2 + Cl2 2HCl
c. I2 + Br2 IBr I2 + Br2 2IBr
d. Fe + S Fe2S3 2Fe + 3S Fe2S3
e. Mg + N2 Mg3N2 3Mg + N2 Mg3N2
f. Fe + O2 Fe2O3 2(2Fe + (3/2)O2 Fe2O3)4Fe + 3O2 2Fe2O3
2. Decomposition
a. SO3 S + O2 2(SO3 S + (3/2)O2)2SO3 2S + 3O2
b. KNO3 KNO2 + O2 2(KNO3 KNO2 + (1/2)O2)2KNO3 2KNO2 + O2
c. HgO Hg + O2 2(HgO Hg + (1/2)O2)2HgO 2Hg + O2
d. H2O H2 + O2 2(H2O H2 + (1/2)O2)2H2O 2H2 + O2
e. H2O2 H2O + O2 2(H2O2 H2O + (1/2)O2)2H2O2 2H2O + O2
f. NO2 N2 + O2 2(NO2 (1/2)N2 + O2)2NO2 N2 + 2O2
g. Na2SO4 10H2O Na2SO4 + H2O Na2SO4 10H2O Na2SO4 + 10H2
h. NaNO3 NaNO2 + O2 2(NaNO3 NaNO2 + (1/2)O2)2NaNO3 2NaNO3 + O2
3. Single displacement
a. K + CuCl2 KCl + Cu 2K + CuCl2 2KCl + Cu
b. Li + Zn(NO3)2 LiNO3 + Zn 2Li + Zn (NO3)2 2LiNO3 + Zn
c. Fe + HNO3 Fe(NO3)3 + H2 2(Fe + 3HNO3 Fe(NO3)3+ (3/2)H2)2Fe + 6HNO3 2Fe(NO3)3 + 3H2
d. Cl2 + NaBr NaCl + Br2 Cl2 + 2NaBr 2NaCl + Br2
e. Zn + Ag2SO4 ZnSO4 +Ag Zn + Ag2SO4 ZnSO4 + 2Ag
f. Al + H2SO4 Al2(SO4)3 + H2 2Al + 3H2SO4 Al2(SO4)3 + 3H2
g. F2 + CuCl2 CuF2 + Cl2 F2 + CuCl2 CuF2 + Cl2
4. Double displacement
a. Ba(NO3)2 + H2SO4 BaSO4 + HNO3
Ba(NO3)2 + H2SO4 BaSO4 + 2HNO3
b. PbCl2 + Na2SO4 PbSO4 + NaCl PbCl2 + Na2SO4 PbSO4 + 2NaCl
c. AgNO3 + K2CrO4 Ag2CrO4 + KNO3
2AgNO3 + K2CrO4 Ag2CrO4 + KNO3
d. B(OH)3 + NaCl NaOH + BCl3 B(OH)3 + 3NaCl 3NaOH + BCl3
e. Ca(NO3)2 + KOH Ca(OH)2 + KNO3
Ca(NO3)2 + 2KOH Ca(OH)2 + 2KNO3
f. Fe(NO3)3 + LiOH Fe(OH)3 + LiNO3
Fe(NO3)3 + 3LiOH Fe(OH)3 + 3LiNO3
g. SnCl4 + Na3PO4 Sn3(PO4)4 + NaCl
3SnCl4 + 4Na3PO4 Sn3(PO4)4 + 12NaCl
5. Neutralization
a. HNO3 + KOH H2O + KNO3 HNO3 + KOH H2O + KNO3
b. HCl + Ca(OH)2 H2O + CaCl2 2HCl + Ca(OH)2 2H2O + CaCl2
c. H2SO4 + LiOH H2O + Li2SO4 H2SO4 + 2LiOH 2H2O + Li2SO4
d. HClO4 + Mg(OH)2 H2O + Mg(ClO4)2
2HClO4 + Mg(OH)2 2H2O + Mg(ClO4)
e. H2SO4 + Ca(OH)2 H2O + CaSO4
H2SO4 + Ca(OH)2 2H2O + CaSO4
f. HCl + NaOH H2O + NaCl HCl + NaOH H2O + NaCl
6. Balance the following equations (Note: the exercises cannot be done until the topics of naming and formula writing of compounds have been learned.)
a. iron(III) hydroxide + sulfuric acid iron(III) sulfate + water
2Fe(OH)3 + 3H2SO4 Fe2(SO4)3 + 6H2O
b. calcium carbonate + nitric acid calcium nitrate + water + carbon
dioxide
CaCO3 + 2HNO3 Ca(NO3)2 + H2O + CO2
c. phosphoric acid + sodium hydroxide sodium phosphate + water
H3PO4 + 3NaOH Na3PO4 + 3H2
d. silver nitrate + cupric chloride barium carbonate + ammonium nitrate
2Ag NO3 + CuCl2 2AgCl + Cu(NO3)
e. barium nitrate + ammonium carbonate
barium carbonate + ammonium nitrate
Ba(NO3)2 + (NH4)2CO3 BaCO3 + 2NH4NO3
f. lead(II) chloride + nitric acid lead(II) nitrate + hydrogen chloride
PbCl2 + 2HNO3 Pb(NO3)2 + 2HCl
g. magnesium chloride + ammonium carbonate ammonium chloride + magnesium carbonate
MgCl2 + (NH4)2CO3 2NH4Cl + MgCO3
h. mercurous nitrate + sodium chloride mercurous chloride + sodium nitrate
Hg2(NO3)2 + 2NaCl Hg2Cl2 + 2NaNO3
i. barium nitrate + sodium hydroxide barium hydroxide + sodium nitrate
Ba(NO3)2 + 2NaOH Ba(OH)2 + 2NaNO3
j. iron + sulfur ferrous sulfide Fe + S FeS
k. aluminum + nitric acid aluminum nitrate + hydrogen
2(Al + 3HNO3 Al(NO3)3 + (3/2)H2)2Al + 6HNO3 2Al(NO3)3 + 3H2
l. calcium oxide + hydrochloric acid CaO + 2HCl CaCl2 + H2
calcium oxide + hydrochloric acid
m. stannic nitrate + potassium sulfate stannic sulfate + potassium nitrate
Sn(NO3)4 + 2K2SO4 Sn (SO4)2 + 4KNO3
n. mercurous oxide mercury +oxygen
2(Hg2O Hg + (1/2)O2) 2Hg2O 2Hg + O2
o. lithium chloride + plumbous nitrate plumbous chloride +lithium nitrate
2LiCl + Pb(NO3)2 PbCl2 + 2LiNO3
p. calcium + aluminum chloride calcium chloride + aluminum
3Ca + 2AlCl3 3CaCl2 + 2Al
q. nitric acid + aluminum hydroxide aluminum nitrate + water
3HNO3 + Al(OH)3 Al(NO3)3 + 3H2O
Stoichiometry
1. In each reaction below 0.5 mole of A reacts to form the products B and C. Using the coefficients in the chemical equation, calculate the moles of B and C produced.
a. A B + 2C
b. A 3B+4C
c. 2A B + 3C
d. 3A 2B + 5C
2. In each reaction below 0.25 mole of compound C is produced. Find the moles of compound A which reacted to produce C.
a. A 2B + C
b. 2A B + 3C
c. 3A 2B + C
d. 4A 5B + 3C
3. How many moles of Fe and CO are produced when 7 moles of CO react with excess Fe2O3?
Fe2O3 + 3CO 2Fe + 3CO2
4. How many moles of Cl2 are produced when 0.5 mole of KMnO4 reacts with excess HCl?
2KMnO4 + 16HCl 2MnCl2+5Cl2 +2KCl+8H2O
5. If 3 moles of aluminum are reacted with excess Mercury (II) chloride, how many moles of mercury and aluminum chloride form?
3HgCl2 + 2Al 3Hg + 2AlCl3
6. (a) If 5 moles of Al react with 7 moles of HgCl2, how many moles of Hg and AlCl3 form? (see previous problem for the reaction.) (b) Find the number of moles of excess reagent leftover.
a. Moles of Hg and AlCl3 formed.
b. Moles of excess reagent leftover.
7. (a) If 9 moles of NH3 react with 13 moles of oxygen, find the number of moles of NO and H2O produced. (b) Find the number of moles of excess reagent leftover. (c) If 13 moles of H2O is actually produced, what is the percent yield of the reaction?
4NH3 + 5O2 4NO + 6H2O
a. Number of moles of NO and H2O produced
b. Number of moles of excess reagent leftover
Excess = O2 = 1.75 moles O2
c. Percent yield of the reaction
8. If 258g of Hexane (C6H14) reacts with excess oxygen, find: (a) the grams of water produced, and (b) the volume of CO2 in milliliters produced at STP.
a. Grams of H2O produced
b. Volume (ml) of CO2 produced at STP
9. If 16g of ethane (C2H6) reacts with excess oxygen, calculate the volume of CO2 produced at STP (in liters). You write the reaction.
10. If 30.63g of KClO3 is decomposed by heating in the presence of a manganese dioxide catalyst, calculate (a) the grams of O2 produced, and, (b) the volume of O2 produced at STP.
a. Grams of O2 produced
b. Volume of O2 produced at STP
11. If 9g of aluminum is placed in aqueous hydrogen chloride, calculate (a) the grams of hydrogen produced, and, (b) the volume of hydrogen in milliliters at STP.
2Al + 6HCl 2AlCl3 + 3H2
a. Grams of H2 produced
b. Volume of H2 in milliliters at STP
12. If 30.75g of cupric carbonate is heated, calculate (a) the volume of CO2 produced at STP, and, (b) the weight of cupric oxide produced.
CuCO3 CuO + CO2
a. Volume of CO2 produced at STP
b. Weight of CuO produced
13. If 8g of CO2 is produced by the following reaction, calculate the number of grams of C5H12 which was burned.
C5H12 + 8O2
5CO2 + 6H2O
14. If 22g of dinitrogen oxide was produced by the following reaction, calculate (a) the number of grams of NH4NO3 which decomposed, (b) the number of grams of H2O produced.
NH4NO3
2H2O + N2O
Grams of NH4NO3 decomposed
b. Grams of H2O produced
15. If 33.6 liters of NO2 is decomposed, find the volumes of N2 and O2
produced at STP.
2NO2 N2 +2O2
16. If 2 liters of N2 reacts with 5 liters of H2 (at STP), calculate the volume of NH3 produced.
N2 + 3H2 2NH3
17. If 49.0g of H2SO4 reacts with 35g of NaOH, calculate the following: (a) the number of grams of Na2SO4 produced, (b) the number of grams of excess reagent remaining, and (c) the percent yield if 50.5g of Na2SO4 was actually obtained.
H2SO4 + 2NaOH 2H2O + Na2SO4
a. Grams Na2SO4 produced
b. Grams of excess reagent
c. Percent yield of Na2SO4
18. If 32.7g of H3PO4 reacts with 39.6g of Ca(OH)2, find: (a) the weight of Ca3(PO4)2 produced, (b). the weight of H2O produced, (c). the weight of excess reagent remaining at the end of the reaction, and (d). the percent yield if 12.0g of H2O is actually obtained.
2H3PO4 + 3Ca(OH)2 6H2O + Ca3(PO4)2
a. Grams of Ca3(PO4)2 produced
b. Grams of H20 produced
c. Grams of excess reagent
d. % yield of H2O produced
19. 60g of the hydrate MgSO4× xH2O is heated, cooled, and re-weighed. The anhydrous MgSO4 weighs 30.00 grams. Find the formula of the hydrate.
MgSO4 × xH2O MgSO4 + xH2O
20. 5.6 liters of CO2 gas is reacted with 10.0 grams of LiOH at STP. (a) find the grams of Li2CO3 produced, (b) find the moles of excess reagent remaining at the end of the reaction.
CO2(g) + 2LiOH Li2CO3 + H2O
a. Grams of Li2CO3 produced
b. Moles of excess reagentFind moles CO2 used
Equiation: 1CO2 uses 2LiOH
So: xCO2 uses .42 LiOH
x - .21 moles CO2 used
Now, moles CO2 unused = .25 - .21 = .04
21. If 10g of calcium is placed in a solution containing 29.5g of nitric acid, calculate the volume of hydrogen produced at STP.
Ca + 2HNO3
Ca(NO3)2 + H2