Solutions to Stoichiometry Homework Problem Set

1. Balance the following equations. Given 10.0 grams of each reactant. How many grams of each product could be produced? What is the total mass of reactants and products when the reaction is complete?
   1. LiOH (s) + H₂SO₄ (aq) --> H₂O (l) + Li₂SO₄ (aq)

      	LiOH	H2SO4	-->	H2O	Li2SO4
      Name	lithium hydroxide	sulfuric acid		dihydrogen monoxide	lithium sulfate
      Balance	2	1		2	1
      MW (g mol-1)	23.948	98.079		18.0153	109.946
      Given (g)	10.0	10.0
      Given (mole)	0.418	0.102
      Use (mole)	0.204	0.102
      Produce (mole)				0.204	0.104
      Final (mole)	0.214	0		0.204	0.104
      Final (g)	5.12	0		3.68	11.4
      Total(g)					20.2

   2. Mg(OH)₂ (aq) + H₃PO₄ (l) --> Mg₃(PO₄)₂ (aq) + H₂O (l)

      	Mg(OH)2	H3PO4	-->	Mg3(PO4)2	H2O
      Name	magnesium hydroxide	phosphoric acid		magnesium phosphate	dihydrogen monoxide
      Balance	3	2		1	6
      MW (g mol-1)	58.3197	97.9925		262.8577	18.0153
      Given (g)	10.0	10.0
      Given (mole)	0.171	0.102
      Use (mole)	0.153	0.102
      Produce (mole)				0.051	0.306
      Final (mole)	0.018	0		0.051	0.306
      Final (g)	1.05	0		13.4	5.51
      Total(g)					19.96

   3. CH₄ (g) + O₂ (g) --> CO₂ (g) + H₂O (g)

      	CH4	O2	-->	CO2	H2O
      Name	methane	oxygen		carbon dioxide	dihydrogen monoxide
      Balance	1	2		1	2
      MW (g mole-1)	16.0425	31.9988		44.0095	18.0153
      Given (g)	10.0	10.0
      Given (mole)	0.623	0.312
      Use (mole)	0.156	0.312
      Produce (mole)				0.156	0.312
      Final (mole)	0.467	0		0.153	0.312
      Final (g)	7.49	0		6.86	5.62
      Total(g)					19.97

   4. C₈H₁₈ (l) + O₂ (g) --> CO₂ (g) + H₂O (g)

      	C8H18	O2	-->	CO2	H2O
      Name	octane	oxygen		carbon dioxide	dihydrogen monoxide
      Balance	2	25		16	18
      MW (g mole-1)	114.2285	31.9988		44.0095	18.0153
      Given (g)	10.0	10.0
      Given (mole)	0.0875	0.312
      Use (mole)	0.0250	0.312
      Produce (mole)				0.200	0.225
      Final (mole)	0.0625	0		0.200	0.225
      Final (g)	7.14	0		8.80	4.05
      Total(g)					19.99

   5. NaCl (aq) + AgNO₃ (aq) --> AgCl (s) + NaNO₃ (aq)

      	NaCl	AgNO3	-->	AgCl	NaNO3
      Name	sodium chloride	silver (I) nitrate		silver (I) chloride	sodium nitrate
      Balance	1	1		1	1
      MW (g mole-1)	58.4425	169.8734		143.3209	84.9947
      Given (g)	10.0	10.0
      Given (mole)	0.171	0.0589
      Use (mole)	0.0589	0.0589
      Produce (mole)				0.0589	0.0589
      Final (mole)	0.112	0		0.0589	0.0589
      Final (g)	6.56	0		8.44	5.01
      Total(g)					20.01

   6. CH₃COOH (aq) + NaHCO₃ (s) --> CO₂ (g) + H₂O (l) + NaCH₃COO (aq)

      	CH3COOH	NaHCO3	-->	CO2	H2O	NaCH3COO
      Name	acetic acid	sodium hydrogen carbonate		carbon dioxide	dihydrogen monoxide	sodium acetate
      Balance	1	1		1	1	1
      MW (g mole-1)	60.0520	84.1166		44.0095	18.0153	82.0304
      Given (g)	10.0	10.0
      Given (mole)	0.166	0.119
      Use (mole)	0.119	0.119
      Produce (mole)				0.119	0.119	0.119
      Final (mole)	0.047	0		0.119	0.119	0.119
      Final (g)	2.8	0		5.24	2.14	9.76
      Total(g)					19.94

2. Balance the following equations. Starting with 25.0 grams of each reactant, how many grams of each product could be produced? What is the total mass of reactants and products when the reaction is complete?
   1. Nitrogen monoxide reacts with ozone (trioxide) to produce nitrogen dioxide and oxygen molecules.

      NO + O₃ --> NO₂ + O₂

      	NO	O3	--&GT	NO2	O2
      Balance	1	1		1	1
      MW (g mole-1)	30.0061	47.9982		46.0055	31.9988
      Given (g)	25.0	25.0
      Given (mole)	0.833	0.521
      Use (mole)	0.521	0.521
      Produce (mole)				0.521	0.521
      Final (mole)	0.312	0		0.521	0.521
      Final (g)	9.37	0		24.0	16.7
      Total(g)					50.07

   2. Iron (III) oxide reacts with zinc metal to produce iron metal and zinc (II) oxide.

      Fe₂O₃ + Zn --> Fe + ZnO

      	Fe2O3	Zn	-->	Fe	ZnO
      Balance	1	3		2	3
      MW (g mole-1)	159.692	65.39		55.847	81.39
      Given (g)	25.0	25.0
      Given (mole)	0.156	0.382
      Use (mole)	0.127	0.382
      Produce (mole)				0.255	0.382
      Final (mole)	0.029	0		0.255	0.382
      Final (g)	4.6	0		14.2	31.1
      Total(g)					49.9

   3. Hydrobromic acid reacts with aluminum metal to produce hydrogen gas and aluminum bromide.

      HBr + Al --> H₂ + AlBr₃

      	HBr	Al	-->	H2	AlBr3
      Balance	6	2		3	2
      MW (g mole-1)	80.912	26.981539		2.01948	266.694
      Given (g)	25.0	25.0
      Given (mole)	0.309	0.926
      Use (mole)	0.309	0.103
      Produce (mole)				0.154	0.103
      Final (mole)	0	0.823		0.154	0.103
      Final (g)	0	22.2		0.311	27.5
      Total(g)					50.01