Question

As weather balloons rise from the earth's surface, the pressure of the atmosphere becomes less, tending to cause the volume of the balloons to expand. However, the temperature is much lower in the upper atmosphere than at sea level. Would this temperature effect tend to make such a balloon expand or contract? Weather balloons do, in fact, expand as they rise. What does this tell you?

Short answer

As weather balloons rise, both pressure and temperature decrease. According to the ideal gas law, decreasing pressure tends to increase the volume, while decreasing temperature tends to decrease the volume. However, since weather balloons do expand as they rise, it tells us that the decrease in pressure has a stronger effect on the expansion than the decrease in temperature.

Step-by-step solution

Ideal gas law equation

Recall the ideal gas law equation, which relates the pressure (P), volume (V), temperature (T), and the number of moles (n) of the gas in a container. The equation is given by: \(PV = nRT\) where R is the ideal gas constant.

Analyze the pressure effect on volume

As the weather balloon rises, the atmospheric pressure (P) decreases. According to the ideal gas law equation, if the pressure decreases while the number of moles (n), gas constant (R), and temperature (T) remain constant, the volume (V) should increase: \(PV = nRT\) If P decreases and n, R, and T are constant, then V must increase.

Analyze the temperature effect on volume

As the weather balloon rises, the temperature (T) in the upper atmosphere also decreases. According to the ideal gas law equation, if the temperature decreases while the number of moles (n), gas constant (R), and pressure (P) remain constant, the volume (V) should decrease: \(PV = nRT\) If T decreases and n, R, and P are constant, then V must decrease.

Determine the dominating effect

Based on our analysis in Steps 2 and 3, we can summarize the effects on the volume of the weather balloon as follows: 1. Decreasing pressure tends to increase the volume. 2. Decreasing temperature tends to decrease the volume. Since the question states that weather balloons expand as they rise, we can conclude that the pressure effect (decreasing pressure leading to an increase in volume) is dominating over the temperature effect (decreasing temperature leading to a decrease in volume). So, the observation that weather balloons expand as they rise tells us that the decrease in pressure has a stronger effect on the expansion than the decrease in temperature.