Question

Predict which of the following changes will cause the volume of the balloon to increase or decrease assuming that the temperature and the gas filling the balloon remain unchanged. Drag the appropriate items to their respective bins.
Standard temperature and pressure (STP) are considered to be 273 K and 1.0 atm.

1. Balloon filled with helium under water at 1.15 atm is released and floats to the surface, which is at STP.
2. Balloon filled with helium at STP floats into the atmosphere where the pressure is 0.5 atm.
3. Balloon filled with helium at STP is submerged under water where the pressure is 1.25 atm.
4. Balloon filled with helium at STP floats into air where the pressure equals 1 atm.

Bins:
a. Volume increases
b. Volume decreases
c. Volume is unchanged

Answer 1

Answer:

1. a

2. a

3. b

4. c

Explanation:

The STP is the Standard conditions of Temperature and Pressure, in these conditions, T = 0°C and P = 1 atm. By the ideal gas law,

PV = nRT

Where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature.

We can observe that pressure and volume are indirect proportional, so when one increase, the other decrease. so:

1. The pressure decreases from 1.15 atm to STP, 1 atm, thus the volume increases.

2. The pressure decreases from STP, 1 atm, to 0.5 atm, thus the volume increases.

3. The pressure increases from STP, 1 atm, to 1.25 atm, thus the volume decreases.

4. The pressure remains constant at 1 atm, thus the volume is unchanged.