Chemistry

Problem

Four speed-distribution curves (I–IV) are obtained for samples of helium gas (atomic mass ≈ 4 u) and argon gas (atomic mass ≈ 40 u) at 300 K and 600 K. Observed characteristics are as follows: • Curve I: narrow peak at about 400 m/s • Curve II: broad peak at about 570 m/s • Curve III: narrow peak at about 1 300 m/s • Curve IV: broad peak at about 1 840 m/s Each curve corresponds to one of the four cases (He 300 K, He 600 K, Ar 300 K, Ar 600 K). Which assignment is most consistent with the observations? a)

\text{I: He }300\,\text{K};\,\text{II: He }600\,\text{K};\,\text{III: Ar }300\,\text{K};\,\text{IV: Ar }600\,\text{K}

\text{I: Ar }300\,\text{K};\,\text{II: Ar }600\,\text{K};\,\text{III: He }300\,\text{K};\,\text{IV: He }600\,\text{K}

\text{I: Ar }600\,\text{K};\,\text{II: Ar }300\,\text{K};\,\text{III: He }300\,\text{K};\,\text{IV: He }600\,\text{K}

\text{I: Ar }300\,\text{K};\,\text{II: Ar }600\,\text{K};\,\text{III: He }600\,\text{K};\,\text{IV: He }300\,\text{K}

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