The density of an ideal gas falls as its temperature and pressure?
Correct answer: B. Increase, Decrease
- A. Decrease, Increase
- B. Increase, Decrease
- C. Falls, Constant
- D. Constant, constant
Explanation
The density of an ideal gas decreases as its temperature increases and its pressure decreases. This is because the density of a gas is proportional to its mass and inversely proportional to its volume. When the temperature of a gas increases, the molecules of the gas move faster and spread out, which increases the volume of the gas. When the pressure of a gas decreases, the volume of the gas increases. Therefore, both an increase in temperature and a decrease in pressure will cause the density of a gas to decrease. The following equation shows the relationship between the density of an ideal gas, its temperature, and its pressure: Density = PM/RT where: P is the pressure of the ga M is the molar mass of the gas R is the ideal gas constant T is the temperature of the gas As you can see from the equation, the density of a gas is inversely proportional to its temperature and directly proportional to its pressure. Therefore, an increase in temperature or a decrease in pressure will cause the density of a gas to decrease.
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About Ideal Gas Equation
The ideal gas equation, PV = nRT, relates pressure, volume, amount and absolute temperature when gas particles are assumed to have negligible volume and no intermolecular forces. Applications include finding molar mass, density or an unknown gas variable, with careful use of Kelvin temperature and consistent units, and comparison with real-gas behaviour.
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