Ratio'ed!
GuacaMOLE
GRAMcrackers
No Limit!
Excessive Much?
Mysterious Miscellaneous
100
Nitrogen dioxide is a dangerous pollutant found in car exhaust. In the atmosphere, it mixes with water to form nitric and nitrous acids as shown below.
2NO2 (g) + H2O (l) → HNO3 (l) + HNO2 (l)
What is the mole ratio between NO2 and H2O?
2 : 1
100
How many moles are in 35.9 g of oxygen (O2)?
1.12 mol O2
100
The formation of ammonia can be seen below:
N2 + 3H2 → 2NH3
If 1.2 g of H2 reacts with an excess of N2, what mass of NH3 will be produced?
6.75 g NH3
100
What is the definition of a limiting reactant?
The original substance in the reaction that determines the amount of product made.
100
What is the difference between a limiting and excess reactant?
The limiting reactant determines the amount of product made in a chemical reaction. The excess reactant is not completely used up in a chemical reaction and is often left over mixed in with the product.
100
What is the limiting reactant in the above chemical reaction?
A
200
TiCl4 + O2 → TiO2 + 2 Cl2
What is the mole ratio between oxygen and chlorine?
1 : 2
200
According to the chemical equation below, if you have 4.00 moles of Al, how many moles of H2 would be produced?
2 Al + 6 HCl → 2 AlCl3 + 3 H2
6 mol H2
200
The masses of reactants and theoretical yields of products for a chemical reaction are shown below.
3 Mg + 2 AlCl3 → 3 MgCl2 + 2 Al
If 18.2 g Mg reacts in the equation above, what is the theoretical yield, in grams, of aluminum (Al)?
13.4 g Al
200
To make a booklet, you need 2 covers, 3 staples, and 10 sheets of paper. You have 50 covers, 100 staples and 300 sheets of paper. How many booklets can you make?
25
200
Sodium and water react according to the reaction
2Na (s) + 2H2O (l) → 2NaOH (aq) + H2(g)
What is the excess reactant when 4 mol Na is added to 2 mol H2O?
Water
200
A pile of leaves is lit on fire, and then covered completely with a fire blanket so that the fire goes out. Identify the limiting reactant in this situation
oxygen
300
2 Al + 6 HCl → 2 AlCl3 + 3 H2
What is the mole ratio between aluminium and hydrochloric acid (HCl) in the above reaction?
2 : 6 or 1 : 3
300
According to the chemical equation below, if you have 18.00 moles of HCl, how many moles of H2 would be produced?
2 Al + 6 HCl → 2 AlCl3 + 3 H2
9 mol H2
300
The masses of reactants and theoretical yields of products for a chemical reaction are shown below.
3 Mg + 2 AlCl3 → 3 MgCl2 + 2 Al
If 18.2 g AlCl3 reacts in the equation above, what is the theoretical yield, in grams, of MgCl2?
19.5 g MgCl2
300
You are assembling model racecars. Each model requires one body, one windshield, one engine, and four tires. Identify the limiting and excess reactants.
You have four bodies, five windshields, three engines and eight tires.
The tires are limiting and everything else is excess
300
Mg2Si(s) + 4H2O(l) → 2Mg(OH)2 (aq) + SiH4(g)
Which of the reactants is in excess if we start with 60.0 g of each reactant?
Water is the excess reactant
300
The masses of reactants and theoretical yields of products for a chemical reaction are shown below.
3 Mg + 2 AlCl3 → 3 MgCl2 + 2 Al
When this reaction was performed in the lab, 2.3 g of aluminum were actually produced. The theoretical yield is calculated to be 4.8 g. What was the percent yield for Al in this experiment?
47.9 % yield
400
C6H12O6 (s) + 6 O2 (g) → 6 CO2 (g) + 6 H2O (l)
What is the mole ratio between oxygen and carbon dioxide?
6 : 6 or 1 : 1
400
Nitrogen dioxide is a dangerous pollutant found in car exhaust. In the atmosphere, it mixes with water to form nitric and nitrous acids as shown below.
2 NO2 (g) + H2O (l) → HNO3 (l) + HNO2 (l)
Using the balanced equation above, how many moles of nitric acid (HNO3) will be produced if 23.0 g of NO2 mixes with rainwater? (Note: the molar mass of NO2 is 46.01 g/mol)
0.25 mol HNO3
400
Titanium (IV) oxide (TiO2) is the white pigment used in many paints. It is produced by burning titanium (IV) chloride in excess oxygen as shown below:
TiCl4 + O2 → TiO2 + 2 Cl2
How many grams of the potentially dangerous by-product, chlorine gas (Cl2) will be produced if 47.48 g of O2 react completely (use the balanced equation above)?
210.4 g O2
400
According to the chemical equation below, if you have 18.00 moles of Al and 4.00 moles of HCl, what is your limiting reactant? [Hint: find how many moles of H2 would be produced.]
2 Al + 6 HCl → 2 AlCl3 + 3 H2
Al would produce 27 mol
HCl would produce 2 mol
HCl produces the least amount of H2, making it the limiting reactant
400
For the reaction of C2H4(g) with O2(g) to form CO2(g) and H2O(g), what reactant is in excess if 5.00 mol C2H4 and 12.0 mol O2 are used in the reaction?
C2H4(g) + 3O2(g) → 2CO2(g) + 2H2O(g)
C2H4 is the excess reactant
400
Fe2O3 + 3CO → 2Fe + 3CO2
If 4.0 mol of Fe2CO3 react completely to produce CO2 and the actual yield of the reaction is 5.9 mol of CO2, what is the percent yield?
49.2 % yield
500
What is the mole ratio between B to A?
1 : 2
500
Nitrogen dioxide is a dangerous pollutant found in car exhaust. In the atmosphere, it mixes with water to form nitric and nitrous acids as shown below.
2 NO2 (g) + H2O (l) → HNO3 (l) + HNO2 (l)
Using the balanced equation above, how many moles of nitrous acid (HNO2) will be produced if 85.0 g of NO2 mixes with rainwater? (Note: the molar mass of NO2 is 46.01 g/mol)
0.9 mol HNO2
500
Titanium (IV) oxide (TiO2) is the white pigment used in many paints. It is produced by burning titanium (IV) chloride in excess oxygen as shown below:
TiCl4 + O2 → TiO2 + 2 Cl2
How many grams of the potentially dangerous by-product, chlorine gas (Cl2) will be produced if 47.48 g of TiCl4 react completely (use the balanced equation above)?
35.44 g Cl2
500
Plant and animal cells use glucose as an energy source in respiration. The net equation for respiration is shown below. Use this information to answer the set of questions below
C6H12O6 (s) + 6 O2 (g) → 6 CO2 (g) + 6 H2O (l)
If 9.0 moles of C6H12O6 and 9.0 moles of O2 react, how many moles of water are formed?
Glucose makes 54 mol of water
Oxygen makes 9 mol of water
Oxygen is the limiting reactant and the true amount is 9 mol of water
500
Sodium and water react according to the reaction
2Na (s) + 2H2O (l) → 2NaOH (aq) + H2(g)
How much excess reactant is left over if 4 mol Na is added to 2 mol H2O?
2 mol of Na remain
500
Fe2O3 + 3CO → 2Fe + 3CO2
If 4.0 g of Fe2CO3 react completely to produce CO2 and the actual yield of the reaction is 1.6 g of CO2, what is the percent yield?
48.4% yield
600
Octane (C8H18) is a high energy hydrocarbon used in combustion reactions. In this combustion reaction, what is the mole ratio between octane and water?
2C8H18 + 25O2 → 18H2O + 16CO2
Mole Ratio:
2C8H18 : 18H2O
or
1 : 9
600
If 11.9 mol Cl2 is reacted with NaOH to produce sodium chloride, water, and NaClO2. How many moles of water are produced?
Balanced chemical equation first:
2Cl2(g) + 4NaOH(aq) → 3NaCl(aq) + NaClO2(aq) + 2H2O(l)
Moles of water:
11.9 mol H2O
600
If solid CaCO3 is mixed with 51.6 g HCl to produce calcium chloride, carbon dioxide, and water, what mass of carbon dioxide will be produced?
31.1 g CO2
600
If 68.1 g solid CaCO3 is mixed with 51.6 g HCl to produce calcium chloride, carbon dioxide, and water, what mass of carbon dioxide will be produced?
Write a balanced chemical equation first:
CaCO3(s) + 2HCl(aq) → CaCl2(aq) + CO2(g) + H2O(l)
Then do calculations:
CaCO3 is the limiting reactant
29.9 g CO2 are produced
600
Mg2Si(s) + 4H2O(l) → 2Mg(OH)2 (aq) + SiH4(g)
How much of the excess reactant remains if we start with 60.0 g of each reactant?
Water is the excess reactant
3.62 g of water will remain after the reaction
600
Final Jeopardy
Octane (C8H18) is a high energy hydrocarbon used in combustion reactions. A chemist used 10 g of both octane and oxygen in the combustion reaction. If the final mass of water is 1 g, what is the percent yield? Was this reaction efficient?
Balanced chemical reaction:
2C8H18 + 25O2 → 18H2O + 16CO2
Limiting reactant: O2
Theoretical yield: 2 g H2O
Percent yield: 50%
Not very efficient