You fill a balloon with 10.0 g of N₂ gas. You wish to add 10.0 g of another gas to make the balloon more than twice as large as it is with only the N₂ (that is, more than twice the original volume). Which gas should you add (assume constant temperature)? A) O₂ B) CO₂ C) CO D) He E) You cannot make the balloon more than twice as large with 10.0 g of any gas.

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Quizplus · Accepted Answer

To make the balloon more than twice as large, we need to add a gas with a molar mass less than that of N₂ (M = 28 g/mol). Helium (He) has a molar mass of 4 g/mol, so it will behave like an ideal gas and occupy more volume per unit mass than N₂. Therefore, adding 10.0 g of He will make the balloon more than twice as large. Choice A (O₂) has a molar mass of 32 g/mol, which is slightly larger than N₂, so it will not significantly increase the volume of the balloon. Choices B (CO₂) and C (CO) have larger molar masses than N₂ and will not significantly increase the volume of the balloon. Choice E is incorrect because He can make the balloon more than twice as large.

You Fill a Balloon with 10