Textbook Question
(c) Room temperature is often assumed to be 25 °C. Calculate the molar volume of an ideal gas at 25 °C and 101.3 kPa pressure.
7. Gases
Standard Temperature and Pressure
Multiple Choice
At standard temperature and pressure (STP), which of the following gases occupies the greatest volume if 1 mole of each is measured?
A
CO_2 occupies the highest volume at STP
B
O_2 occupies the highest volume at STP
C
All gases listed occupy the same volume at STP
D
N_2 occupies the highest volume at STP
Verified step by step guidance1
Recall the definition of standard temperature and pressure (STP), which is 0°C (273.15 K) and 1 atm pressure.
Understand that at STP, one mole of any ideal gas occupies the same volume, according to Avogadro's law.
Avogadro's law states that equal volumes of gases at the same temperature and pressure contain an equal number of molecules, so volume depends only on the amount of gas (moles), not the type of gas.
Since the problem states 1 mole of each gas (CO_2, O_2, N_2) at STP, each gas will occupy the same volume regardless of molecular weight or gas identity.
Therefore, the volume occupied by 1 mole of any ideal gas at STP is the same, approximately 22.4 liters.
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