Multiple Choice
How many grams of NaCl are required to prepare 50 mL of a 1 M NaCl solution?
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3. Chemical Reactions
Stoichiometry
Multiple Choice
When 25.5 grams of NaHCO3 decompose completely, what mass of CO2 is produced? (Molar masses: NaHCO3 = 84.0 g/mol, CO2 = 44.0 g/mol)
A
44.0 grams
B
13.4 grams
C
25.5 grams
D
6.7 grams
Verified step by step guidance1
Write the balanced chemical equation for the decomposition of sodium bicarbonate (NaHCO\_3):
\[\mathrm{2\ NaHCO\_3 \rightarrow Na\_2CO\_3 + CO\_2 + H\_2O}\]
Calculate the number of moles of NaHCO\_3 decomposed using its molar mass:
\[\text{moles of NaHCO\_3} = \frac{\text{mass of NaHCO\_3}}{\text{molar mass of NaHCO\_3}} = \frac{25.5\ \mathrm{g}}{84.0\ \mathrm{g/mol}}\]
Use the mole ratio from the balanced equation to find the moles of CO\_2 produced. According to the equation, 2 moles of NaHCO\_3 produce 1 mole of CO\_2, so:
\[\text{moles of CO\_2} = \frac{1}{2} \times \text{moles of NaHCO\_3}\]
Calculate the mass of CO\_2 produced by multiplying the moles of CO\_2 by its molar mass:
\[\text{mass of CO\_2} = \text{moles of CO\_2} \times 44.0\ \mathrm{g/mol}\]
This final value will give you the mass of CO\_2 produced from the complete decomposition of 25.5 grams of NaHCO\_3.
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