在标准状况下，11.2 L 的二氧化碳气体中所含的分子数约为多少？（NA 取 6.02 × 10^23 mol^-1）
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Correct answer
B. 3.01 × 10^23
Principle or equation
标准状况下，气体摩尔体积为 22.4 L/mol。物质的量 n = V / Vm，分子数 N = n × NA。
Why this answer is correct
n(CO2) = 11.2 L / 22.4 L/mol = 0.500 mol，N = 0.500 mol × 6.02 × 10^23 mol^-1 = 3.01 × 10^23。
Example
例如，标准状况下 5.6 L 氧气，n = 5.6/22.4 = 0.25 mol，分子数为 0.25 × 6.02×10^23 = 1.505×10^23。
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