10.8 g of aluminium reacts with excess oxygen to form aluminium oxide: 4Al + 3O2 → 2Al2O3. What is the theoretical yield of aluminium oxide? (Relative masses: Al = 27.0, Al2O3 = 102.0)
40.8 g
20.4 g
10.2 g
What happens to the percentage yield if some product stays on the filter paper after filtration?
It increases
It stays the same
It decreases
How does the actual yield of a reaction usually compare with the theoretical yield?
It's the same
It's more
It's less
In a reaction, the theoretical yield was 80 g, but the actual yield was 60 g. What was the percentage yield?
75%
133%
50%
What volume does 1 mol of a gas occupy at room temperature and pressure?
24 cm3
12 dm3
24 dm3
How many moles of oxygen molecules are there in 48 dm3 of oxygen gas?
1
2
4
Which occupies the greatest volume at room temperature and pressure?
0.5 mol of ammonia, NH3
2 mol of argon, Ar
1 mol of oxygen, O2
What is the volume of 0.25 mol of hydrogen, H2, at room temperature and pressure?
0.25 × 2 × 24 = 12 dm3
0.25 × 24 = 6.0 dm3
\(\frac{24}{0.25}\) = 96 dm3
What is the mass of 6.0 dm3 of carbon dioxide? (Relative formula mass = 44.0)
\(\frac{(44.0 × 6.0)}{24}\) = 11.0 g
\(\frac{(44.0 × 24)}{6.0}\) = 176 g
\(\frac{(6.0 × 24)}{44.0}\) = 3.3 g
Calcium carbonate decomposes to form calcium oxide and carbon dioxide: CaCO3(s) → CaO(s) + CO2(g). What volume of carbon dioxide can be produced from 0.5 mol of calcium carbonate?
48 dm3