Multiple Choice
When one formula unit of CaCl_2 dissolves completely in water, how many individual ions are produced?
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3. Chemical Reactions
Stoichiometry
Multiple Choice
When 13.2 mol of Na reacts with excess water according to the equation 2 Na + 2 H_2O → 2 NaOH + H_2, what mass of hydrogen gas (H_2) is produced?
A
26.4 mol × 2.02 g/mol = 53.3 g
B
13.2 mol × 1 mol H_2 / 2 mol Na × 2.02 g/mol = 13.3 g
C
26.4 g
D
13.2 g
Verified step by step guidance1
Identify the balanced chemical equation: \(2 \text{Na} + 2 \text{H}_2\text{O} \rightarrow 2 \text{NaOH} + \text{H}_2\).
Determine the mole ratio between sodium (Na) and hydrogen gas (H_2) from the balanced equation. For every 2 moles of Na, 1 mole of H_2 is produced.
Calculate the moles of hydrogen gas produced using the mole ratio: \(\text{moles of } H_2 = 13.2 \text{ mol Na} \times \frac{1 \text{ mol } H_2}{2 \text{ mol Na}}\).
Find the molar mass of hydrogen gas (H_2), which is approximately 2.02 g/mol.
Calculate the mass of hydrogen gas produced by multiplying the moles of H_2 by its molar mass: \(\text{mass of } H_2 = \text{moles of } H_2 \times 2.02 \text{ g/mol}\).
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