Question regarding Ideal Gas Assumptions

[GoBlue24]

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I wasn't sure about these statements. Which of the following is an assumption made for ideal gases? \

A) Gas molecules have no volume
B) Pressure is caused by collisions with the walls of a container
C) All collisions between molecules are elastic
D) Both A and C

The answer was D. I understand that A and C are correct. The volume of gas is negligible (at low pressures) and the collisions between molecules are definitely elastic because there is no loss of K.E. from collisions between molecules (only temp. can change average K.E.). HOWEVER, I thought pressure was caused by collisions with the walls of a container? Why is this not the case? I know I'm missing something.

Can anyone give me a very good (possibly, in depth) reason?

 

[ttpharm]

Volume is large so they don't take into account collision with wall.

 

[TXpredent]

I guess since it assumes low pressure, there's not that many collisions going on with the wall of the container so it's just not taken into account. I'm definitely not a gas expert though, so please don't hurt me!

 

[James35]

I think the question is asking what are the specific assumtions associated with the ideal gas law. There are like 3 or so. A & C being two explicitly stated assumptions that make the equations for the ideal gas law true.

The pressure caused by collisions with the container might be true, but it is not an assumption of the ideal gas law. It is just a random fact. They could have said the equilibrium constant for a given reaction (A + B --> C + D) is Keq= [C][D]/[A]. It's true, but has nothing to do with assumptions of the ideal gas law.

Also, "assumptions of the ideal gas law" in this question means what assumptions had to take place to make the ideal gas law true. This is much different than what assumptions can you make about nature given the ideal gas law.

 

[Muelitas]

The way i see this: there are collisions made with the container, but they aren't due to pressure, they are due to High temperature. Remember, in the ideal gas assumption, temperature is favored at high temps and pressure is favored when it's low. Hope this helps!

 

[ttpharm]

people are just guessing here. BOYLES LAW PEOPLE.

Edit: If their answer starts with "I think" "I guess", don't trust.