SCH3U GRADE 11 CHEMISTRY UNIT 3
TEST | QUESTIONS AND ANSWERS | 2026
UPDATE | 100% CORRECT - ONTARIO
VIRTUAL SCHOOL.
SECTION 1: THE MOLE AND MOLAR MASS
QUESTION 1
How many particles are in one mole of any substance?
A) 3.00 × 10⁸
B) 6.02 × 10²³
C) 1.00 × 10²³
D) 6.02 × 10²²
Correct Answer: B – 6.02 × 10²³
Rationale: One mole of any substance contains Avogadro's
constant: 6.02×10236.02×1023 particles .
QUESTION 2
What is the molar mass of magnesium nitrate, Mg(NO₃)₂? (Mg = 24.31, N = 14.01,
O = 16.00 g/mol)
, A) 86.31 g/mol
B) 106.32 g/mol
C) 148.33 g/mol
D) 54.32 g/mol
Correct Answer: C – 148.33 g/mol
Rationale:
Mg: 24.31 g/mol
N: 14.01 × 2 = 28.02
O: 16.00 × 6 = 96.00
Total = 24.31 + 28.02 + 96.00 = 148.33 g/mol
QUESTION 3
How many moles are present in 8.5 g of Mg(NO₃)₂?
A) 0.0573 mol
B) 0.073 mol
C) 0.12 mol
D) 0.00573 mol
Correct Answer: A – 0.0573 mol
Rationale: Moles = mass / molar
mass. n=8.5 g/148.33 g/mol=0.0573 moln=8.5 g/148.33 g/mol=0.0573 mol .
QUESTION 4
How many atoms are there in 8.5 g of Mg(NO₃)₂?
A) 3.45 × 10²² atoms
B) 3.45 × 10²³ atoms
C) 3.45 × 10²² atoms (but in a single formula unit there are 11 atoms; total atoms
TEST | QUESTIONS AND ANSWERS | 2026
UPDATE | 100% CORRECT - ONTARIO
VIRTUAL SCHOOL.
SECTION 1: THE MOLE AND MOLAR MASS
QUESTION 1
How many particles are in one mole of any substance?
A) 3.00 × 10⁸
B) 6.02 × 10²³
C) 1.00 × 10²³
D) 6.02 × 10²²
Correct Answer: B – 6.02 × 10²³
Rationale: One mole of any substance contains Avogadro's
constant: 6.02×10236.02×1023 particles .
QUESTION 2
What is the molar mass of magnesium nitrate, Mg(NO₃)₂? (Mg = 24.31, N = 14.01,
O = 16.00 g/mol)
, A) 86.31 g/mol
B) 106.32 g/mol
C) 148.33 g/mol
D) 54.32 g/mol
Correct Answer: C – 148.33 g/mol
Rationale:
Mg: 24.31 g/mol
N: 14.01 × 2 = 28.02
O: 16.00 × 6 = 96.00
Total = 24.31 + 28.02 + 96.00 = 148.33 g/mol
QUESTION 3
How many moles are present in 8.5 g of Mg(NO₃)₂?
A) 0.0573 mol
B) 0.073 mol
C) 0.12 mol
D) 0.00573 mol
Correct Answer: A – 0.0573 mol
Rationale: Moles = mass / molar
mass. n=8.5 g/148.33 g/mol=0.0573 moln=8.5 g/148.33 g/mol=0.0573 mol .
QUESTION 4
How many atoms are there in 8.5 g of Mg(NO₃)₂?
A) 3.45 × 10²² atoms
B) 3.45 × 10²³ atoms
C) 3.45 × 10²² atoms (but in a single formula unit there are 11 atoms; total atoms
