Copper is produced from copper(II) oxide using carbon: 2CuO + C → 2Cu + CO₂ 20.0 g of copper(II) oxide reacts and produces 12.0 g of copper. Calculate the percentage yield of copper.
75%
Which reactant determines the amount of product formed?
The limiting reactant
What is the formula for percentage yield?
(actual yield ÷ theoretical yield) × 100
What is meant by “conservation of mass”?
No atoms are lost or made. Mass of reactants = mass of products
Why is percentage yield often less than 100%?
SPECIFIC product is lost during the reaction
Calculate the mass of sodium in 1 mole of NaCl (Na = 23).
23 g
Calculate the volume of 0.25 moles of gas at RTP.
6 dm³
What is the mass of 1 mole of hydrogen?
2 g
Method 1: C₂H₄ + H₂O → C₂H₅OH Method 2: C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂ Which is better for the environment.
Method 1 (less waste produced)
What is the unit of mass used in quantitative chemistry?
grams (g)
2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O 25.0 cm³ of sodium hydroxide solution of concentration 8.0 g/dm³ reacts with excess sulfuric acid. Calculate the mass of sodium sulfate produced.
0.355 g
What is meant by “excess reactant”?
A reactant left over after the reaction/too much added
A reaction has an atom economy of 100%. What does this mean?
All products are desired
Zn + 2HCl → ZnCl₂ + H₂ 6.5 g of zinc reacts with 100 cm³ of hydrochloric acid of concentration 2.0 g/dm³. Calculate the volume of hydrogen produced at RTP.
0.066 dm³ (66 cm³)
What is the unit for amount of substance?
mol.
What is the RFM of oxygen?
32
What is the formula to calculate the number of moles?
moles = mass ÷ RFM
What does a low atom economy indicate?
A lot of waste is produced
CaCO₃ + 2HCl → CaCl₂ + CO₂ + H₂O 10.0 g of calcium carbonate reacts with 150 cm³ of hydrochloric acid of concentration 4.0 g/dm³. Calculate the volume of carbon dioxide produced at RTP.
0.197 dm³ (197 cm³)
Convert 250 cm³ into dm³.
0.25 dm³
Calculate the volume of 2 moles of gas at RTP.
48 dm³
Calculate the mass of 0.5 moles of magnesium (Mr = 24).
12 g
What volume does one mole of gas occupy at room temperature and pressure (RTP)?
24 dm³
What is the formula for atom economy?
RFM of desired product ÷ total RFM of reactants) × 100
Calculate the number of moles in 10 g of calcium carbonate.
0.1 mol
Calcium carbonate decomposes according to the equation: CaCO₃ → CaO + CO₂ 12.5 g of calcium carbonate produces 5.0 g of calcium oxide. Calculate the percentage yield of calcium oxide.
71.4%
Why is a high atom economy desirable?
Less waste
Fe + S → FeS 14.0 g of iron reacts with 10.0 g of sulfur and produces 18.0 g of iron(II) sulfide. Calculate the percentage yield of iron(II) sulfide.
81.8%
Reaction 1: N₂ + 3H₂ → 2NH₃ Reaction 2: 2NH₄Cl + Ca(OH)₂ → 2NH₃ + CaCl₂ + 2H₂O Which is more sustainable.
Reaction 1
What is the formula to calculate concentration?
concentration = mass ÷ volume OR concentration = moles ÷ volume
2Al + 6HCl → 2AlCl₃ + 3H₂ 5.4 g of aluminium reacts with excess hydrochloric acid. Calculate the volume of hydrogen produced at RTP.
7.2 dm³
What does “theoretical yield” mean?
The maximum possible product
Calculate the number of moles in 48 g of oxygen (Mr = 32).
1.5 mol
Calculate the concentration if 5 g of solute is dissolved in 2 dm³ of solution.
2.5 g/dm³
What is this number called? (6.02 × 10²³)
Avogadro constant
Calculate the percentage yield if the theoretical yield is 20 g and the actual yield is 15 g.
75%
What is the unit of concentration?
g/dm³ or mol/dm³
Lead(II) nitrate decomposes when heated: 2Pb(NO₃)₂ → 2PbO + 4NO₂ + O₂ 33.1 g of lead(II) nitrate produces 20.0 g of lead(II) oxide. Calculate the percentage yield of lead(II) oxide.
89.7%
In the equation: 2H₂ + O₂ → 2H₂O, how many moles of water form from 2 moles of hydrogen?
2 moles
Mg + 2HCl → MgCl₂ + H₂ 5.0 g of magnesium reacts with 20.0 g of hydrochloric acid. Calculate the maximum mass of magnesium chloride that can be produced.
19.8 g
Calculate the concentration if 10 g of solute is dissolved in 1 dm³ of solution.
10 g/dm³
How many particles are in one mole of a substance?
6.02 × 10²³
What is the formula for calculating gas volume at RTP?
volume = moles × 24
What is meant by a limiting reactant?
The reactant that runs out first
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