Which of the following desceriptions about ideal gas is/are correct?
1)An ideal gas obeys Boyle's law only under high temp and low pressure
2)the molecules of an ideal gas have no size
3)the internal energy of an ideal gas consists of kinetic energy only
A.1)only B.3)only
C.1)&2) D.2)&3)
THE ANS IS D but not 1,2,3 are correct,why?
1) nonsense
2) nonsense
3) Yes
1. is wrong by definition. An ideal gas obeys the ideal gas laws
2 is correct because the molecules of an IDEAL gas are considered POINT masses
3 is correct because internal energy depends only on temperature, how fast the molecules move.
The correct answer is D) 2) and 3) only.
Let's go through each option and explain why they are correct or incorrect:
1) "An ideal gas obeys Boyle's law only under high temperature and low pressure."
This statement is incorrect. In reality, an ideal gas obeys Boyle's law at any temperature and pressure. Boyle's law states that at constant temperature, the volume of a given amount of gas is inversely proportional to its pressure. Therefore, option 1) is not correct.
2) "The molecules of an ideal gas have no size."
This statement is correct. In the ideal gas model, it is assumed that gas molecules have no size, occupy no volume, and do not interact with each other. This simplification allows for easier mathematical calculations and predictions. Therefore, option 2) is correct.
3) "The internal energy of an ideal gas consists of kinetic energy only."
This statement is correct. According to the kinetic theory of gases, the internal energy of an ideal gas consists solely of the kinetic energy of its molecules. The ideal gas model assumes that the gas molecules are in constant motion and do not possess potential energy or any other form of internal energy, such as chemical potential energy. Therefore, option 3) is correct.
Since only options 2) and 3) are correct, the answer is D) 2) and 3) only.