Question

continued...
part c. fill in the chart
substance\tmoles (mol)\tmass (g)

1. \tk₂so₄\t0.25\t?
2. \tlif\t?\t
3. \tmg(oh)₂\t0.10\t?
4. \tnh₃\t?\t34.06
5. \tpo₄\t\t?

part d. challenge

1. which weighs more: 1 mole of h₂o or 1 mole of ch₄?

1. you have 25 g of h₂o and 25 g of ch₄. which sample contains more moles?

1. a reaction requires 0.50 mole of na₂co₃ and 0.75 mole of kbr. calculate the mass of each substance and determine which is heavier.

1. a chemist mixes 2.5 moles of naoh with 2.5 moles of koh. calculate the total mass of the mixture

1. which weighs more: 1 mole of cao or 1 mole of bao?

Explanation:

Part C (Taking Question 11 as an example)

Step1: Calculate molar mass of \( K_2SO_4 \)

Molar mass of \( K = 39.10 \, g/mol \), \( S = 32.07 \, g/mol \), \( O = 16.00 \, g/mol \).
Molar mass of \( K_2SO_4 = 2\times39.10 + 32.07 + 4\times16.00 = 174.27 \, g/mol \).

Step2: Use \( \text{Mass} = \text{Moles} \times \text{Molar Mass} \)

Given moles = \( 0.25 \, mol \), so mass = \( 0.25 \times 174.27 = 43.5675 \, g \approx 43.57 \, g \).

Part D (Taking Question 16 as an example)

Step1: Calculate molar mass of \( H_2O \)

Molar mass of \( H = 1.01 \, g/mol \), \( O = 16.00 \, g/mol \).
Molar mass of \( H_2O = 2\times1.01 + 16.00 = 18.02 \, g/mol \).

Step2: Calculate molar mass of \( CH_4 \)

Molar mass of \( C = 12.01 \, g/mol \), \( H = 1.01 \, g/mol \).
Molar mass of \( CH_4 = 12.01 + 4\times1.01 = 16.05 \, g/mol \).

Step3: Compare molar masses

Since \( 18.02 > 16.05 \), 1 mole of \( H_2O \) weighs more.

Part C (Question 11) Answer: \( \approx 43.57 \, g \)

Part D (Question 16) Answer: 1 mole of \( H_2O \) weighs more.

(For other questions in Part C and D, follow similar steps: calculate molar mass, then use \( \text{Mass} = \text{Moles} \times \text{Molar Mass} \) or compare molar masses for mole - mass conversions and comparisons.)

Answer:

Step1: Calculate molar mass of \( H_2O \)

Molar mass of \( H = 1.01 \, g/mol \), \( O = 16.00 \, g/mol \).
Molar mass of \( H_2O = 2\times1.01 + 16.00 = 18.02 \, g/mol \).

Step2: Calculate molar mass of \( CH_4 \)

Molar mass of \( C = 12.01 \, g/mol \), \( H = 1.01 \, g/mol \).
Molar mass of \( CH_4 = 12.01 + 4\times1.01 = 16.05 \, g/mol \).

Step3: Compare molar masses

Since \( 18.02 > 16.05 \), 1 mole of \( H_2O \) weighs more.

Part C (Question 11) Answer: \( \approx 43.57 \, g \)

Part D (Question 16) Answer: 1 mole of \( H_2O \) weighs more.

(For other questions in Part C and D, follow similar steps: calculate molar mass, then use \( \text{Mass} = \text{Moles} \times \text{Molar Mass} \) or compare molar masses for mole - mass conversions and comparisons.)