NEET Some Basic Concepts Of Chemistry — Set 17

Question 1

What is the mass of $ \ce{CaCO3} $ required to react with 50 mL of 2 M $ \ce{HCl} $? (Molar mass: $ \ce{CaCO3} $ = 100 g/mol)

Accepted Answer

Reaction: $ \ce{CaCO3 + 2HCl -> CaCl2 + CO2 + H2O} $. Moles of $ \ce{HCl} $ = 2 × 0.05 = 0.1 mol. 0.1 mol $ \ce{HCl} $ needs 0.05 mol $ \ce{CaCO3} $ = 0.05 × 100 = 5 g.

Question 2

What volume of $ \ce{O2} $ at STP is required to burn 11 g of $ \ce{C2H6} $ completely to $ \ce{CO2} $ and $ \ce{H2O} $? (Molar mass: $ \ce{C2H6} $ = 30 g/mol)

Accepted Answer

Reaction: $ \ce{2C2H6 + 7O2 -> 4CO2 + 6H2O} $. Moles of $ \ce{C2H6} $ = $ \frac{11}{30} $ ≈ 0.3667 mol. 2 mol $ \ce{C2H6} $ need 7 mol $ \ce{O2} $; 0.3667 mol need $ \frac{7}{2} $ × 0.3667 ≈ 1.2833 mol. Volume = 1.2833 × 22.4 ≈ 28.75 L.

Question 3

What is the mass of $ \ce{PbSO4} $ produced when 33.1 g of $ \ce{Pb(NO3)2} $ reacts with excess $ \ce{H2SO4} $? (Molar masses: $ \ce{Pb(NO3)2} $ = 331 g/mol, $ \ce{PbSO4} $ = 303 g/mol)

Accepted Answer

Reaction: $ \ce{Pb(NO3)2 + H2SO4 -> PbSO4 + 2HNO3} $. Moles of $ \ce{Pb(NO3)2} $ = $ \frac{33.1}{331} $ = 0.1 mol. 1 mol $ \ce{Pb(NO3)2} $ produces 1 mol $ \ce{PbSO4} $; mass = 0.1 × 303 = 30.3 g.

NEET Chemistry: Some Basic Concepts Of Chemistry — Practice Set 17

Q1. What is the mass of \( \ce{CaCO3} \) required to react with 50 mL of 2 M \( \ce{HCl} \)? (Molar mass: \( \ce{CaCO3} \) = 100 g/mol)

Q2. What volume of \( \ce{O2} \) at STP is required to burn 11 g of \( \ce{C2H6} \) completely to \( \ce{CO2} \) and \( \ce{H2O} \)? (Molar mass: \( \ce{C2H6} \) = 30 g/mol)

Q3. What is the mass of \( \ce{PbSO4} \) produced when 33.1 g of \( \ce{Pb(NO3)2} \) reacts with excess \( \ce{H2SO4} \)? (Molar masses: \( \ce{Pb(NO3)2} \) = 331 g/mol, \( \ce{PbSO4} \) = 303 g/mol)

Q4. A 0.1 M \( \ce{KOH} \) solution is diluted by adding 200 mL of water to 100 mL of the original solution. What is the final molarity?

Q5. A compound contains 32.43% sodium, 22.52% sulfur, and 45.05% oxygen by mass. What is its empirical formula? (Atomic masses: Na = 23, S = 32, O = 16)

Q6. A solution of \( \ce{HNO3} \) has a molarity of 1.5 M and a density of 1.05 g/mL. What is its molality? (Molar mass: \( \ce{HNO3} \) = 63 g/mol)

Q7. How many significant figures are present in the result of \( \frac{0.0894 \times 298.15}{0.0821} \)?

Q8. What is the mass of \( \ce{KClO3} \) required to produce 2.24 L of \( \ce{O2} \) at STP with 50% decomposition efficiency? (Molar mass: \( \ce{KClO3} \) = 122.5 g/mol)

Q9. A 0.3 M \( \ce{HCl} \) solution is diluted by adding 400 mL of water to 100 mL of the original solution. What is the final molarity?

Q10. What is the mass percentage of \( \ce{KNO3} \) in a solution made by dissolving 10.1 g of \( \ce{KNO3} \) in 39.9 g of water? (Molar mass: \( \ce{KNO3} \) = 101 g/mol)