Which of the following would cause a decrease in the volume of a sealed balloon filled with helium? adding oxygen gas decreasing temperature adding more helium decreasing pressure

## Step 1<br />The volume of a gas is determined by the ideal gas law, which states that the volume of a gas is directly proportional to the temperature and inversely proportional to the pressure, assuming the amount of gas and the gas constant are constant. This is represented by the formula:<br />### \( V = \frac{nRT}{P} \)<br />where \( V \) is the volume, \( n \) is the number of moles of gas, \( R \) is the gas constant, \( T \) is the temperature, and \( P \) is the pressure.<br /><br />## Step 2<br />Adding oxygen gas to the balloon would not decrease the volume of the balloon. This is because the volume of a gas is not affected by the type of gas, but rather by the temperature and pressure.<br /><br />## Step 3<br />Adding more helium to the balloon would not decrease the volume of the balloon. This is because the volume of a gas is not affected by the amount of gas, but rather by the temperature and pressure.<br /><br />## Step 4<br />Decreasing the temperature of the balloon would decrease the volume of the balloon. This is because the volume of a gas is directly proportional to the temperature. When the temperature decreases, the volume of the gas also decreases.<br /><br />## Step 5<br />Decreasing the pressure of the balloon would increase the volume of the balloon. This is because the volume of a gas is inversely proportional to the pressure. When the pressure decreases, the volume of the gas increases.