NEET Some Basic Concepts Of Chemistry — Set 16

Question 1

A solution contains 10 ppm of $ \ce{SO2} $ by mass in water. What is the molarity if the density of the solution is 1 g/mL? (Molar mass: $ \ce{SO2} $ = 64 g/mol)

Accepted Answer

10 ppm = 10 g $ \ce{SO2} $ in 10⁶ g solution. Volume = $ \frac{10⁶}{1} $ = 10⁶ mL = 1000 L. Moles = $ \frac{10}{64} $ ≈ 0.15625 mol; molarity = $ \frac{0.15625}{1000} $ ≈ 1.5625 × 10⁻⁴ M.

Question 2

A 0.84 g sample of a hydrocarbon produces 2.64 g of $ \ce{CO2} $ and 1.08 g of $ \ce{H2O} $ on complete combustion. What is its molecular formula if its molar mass is 84 g/mol? (Atomic masses: C = 12, H = 1, O = 16)

Accepted Answer

Mass of C = $ \frac{12}{44} $ × 2.64 ≈ 0.72 g; mass of H = $ \frac{2}{18} $ × 1.08 = 0.12 g. Total = 0.72 + 0.12 = 0.84 g (matches). Moles: C = $ \frac{0.72}{12} $ = 0.06, H = $ \frac{0.12}{1} $ = 0.12; ratio = 1 : 2; empirical formula = $ \ce{CH2} $, mass = 14 g/mol. $ n = \frac{84}{14} = 6 $; molecular formula = $ \ce{C6H12} $.

Question 3

A gas occupies 3.36 L at STP and weighs 4.8 g. What is its molar mass?

Accepted Answer

Moles = $ \frac{3.36}{22.4} $ = 0.15 mol. Molar mass = $ \frac{4.8}{0.15} $ = 32 g/mol.

NEET Chemistry: Some Basic Concepts Of Chemistry — Practice Set 16

Q1. A solution contains 10 ppm of \( \ce{SO2} \) by mass in water. What is the molarity if the density of the solution is 1 g/mL? (Molar mass: \( \ce{SO2} \) = 64 g/mol)

Q2. A 0.84 g sample of a hydrocarbon produces 2.64 g of \( \ce{CO2} \) and 1.08 g of \( \ce{H2O} \) on complete combustion. What is its molecular formula if its molar mass is 84 g/mol? (Atomic masses: C = 12, H = 1, O = 16)

Q3. A gas occupies 3.36 L at STP and weighs 4.8 g. What is its molar mass?

Q4. How many grams of \( \ce{Na2SO4} \) are produced when 8 g of \( \ce{NaOH} \) reacts with excess \( \ce{H2SO4} \)? (Molar masses: \( \ce{NaOH} \) = 40 g/mol, \( \ce{Na2SO4} \) = 142 g/mol)

Q5. A 0.42 g sample of a hydrocarbon produces 1.32 g of \( \ce{CO2} \) and 0.54 g of \( \ce{H2O} \) on complete combustion. What is its molecular formula if its molar mass is 42 g/mol? (Atomic masses: C = 12, H = 1, O = 16)

Q6. What volume of \( \ce{N2} \) at STP is required to react with 6 g of \( \ce{H2} \) to produce \( \ce{NH3} \) with 60% yield? (Molar mass: \( \ce{H2} \) = 2 g/mol)

Q7. What mass of \( \ce{N2} \) reacts with 6 g of \( \ce{H2} \) to form \( \ce{NH3} \), if \( \ce{H2} \) is the limiting reagent? (Molar masses: \( \ce{N2} \) = 28 g/mol, \( \ce{H2} \) = 2 g/mol)

Q8. A 400 mL solution contains 14.6 g of \( \ce{HCl} \) and has a density of 1.02 g/mL. What is its molarity? (Molar mass: \( \ce{HCl} \) = 36.5 g/mol)

Q9. What volume of \( \ce{CO2} \) at STP is produced when 10 g of \( \ce{C4H10} \) is burned completely? (Molar mass: \( \ce{C4H10} \) = 58 g/mol)

Q10. A mixture of 10 g \( \ce{C} \) and 24 g \( \ce{O2} \) is ignited to form \( \ce{CO2} \). What is the mass of \( \ce{CO2} \) produced? (Atomic masses: C = 12, O = 16)