CIE iGCSE Co-Ordinated Science C3.3 The mole and the Avogadro constant Exam Style Questions Paper 2
Question
A sample of methane has mass 16.0 g at r.t.p. and contains the Avogadro number of molecules.
What is the volume of 4.0 g of methane at r.t.p.?
(A) 4.0 dm3
(B) 6.0 dm3
(C) 16 dm3
(D) 24 dm3
▶️Answer/Explanation
Ans : B
Question
When magnesium carbonate reacts with dilute hydrochloric acid, carbon dioxide gas is released.
The equation for this reaction is shown.
MgCO$_{3}$ + 2HCl → MgCl$_{2}$ + CO$_{2}$ + H$_{2}$O
Which volume of carbon dioxide, collected at room temperature and pressure, is released when 4.2 g of magnesium carbonate reacts with excess dilute hydrochloric acid?
(A) 1.2 dm$^{3}$
(B) 2.4 dm$^{3}$
(C) 4.8 dm$^{3}$
(D) 12 dm$^{3}$
▶️Answer/Explanation
Ans: A
Question
Which statements about the mole are correct?
1 One mole of 12C contains twice as many atoms as one mole of 24Mg.
2 One mole of 12C has a mass of 12 g.
3 One mole of C contains Avogadro’s number of atoms.
4 One mole of oxygen gas at room temperature and pressure occupies 32dm3
.
A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4
▶️Answer/Explanation
Ans : C
Question
1 g of hydrogen contains 6 × 10$^{23}$ atoms.
The relative atomic mass of helium is 4.
How many atoms does 1 g of helium contain?
(A) 1.5 × 10$^{23}$
(B) 3 × 10$^{23}$
(C) 6 × 10$^{23}$
(D) 2.4 × 10$^{24}$
▶️Answer/Explanation
Ans: A