Question

if the temperature of this balloon were to decrease suddenly, how would the balloon change? a its volume would decrease. b its mass would decrease. c its volume would increase. d its mass would increase.

Explanation:

When the temperature of a gas (inside the balloon) decreases, according to Charles's Law ($V\propto T$ when pressure is constant), the volume of the gas decreases. Mass is an intrinsic property of matter and is not affected by temperature changes. So, the volume of the balloon would decrease while its mass remains the same.

Answer:

A. Its volume would decrease.