- #1

WolfeSieben

- 20

- 0

I'm a first timer on this forum and am hoping to get some help.

## Homework Statement

4.00×10^23 nitrogen molecules collide with a 18.0 cm^2 wall each second. Assume that the molecules all travel with a speed of 350 m/s and strike the wall head on.

## Homework Equations

F = MA

Pressure (Pascals) = Newtons/M^2

Avagraddo's Number = 6.02 x 10^23 molecules per mole

## The Attempt at a Solution

Alright, so I'm not sure what I did wrong here so I'm hoping someone here can help.

To start I figured out the weight of the nitrogen molecules:

(4.00 x 10^23 molecules of N2)/(6.02 x 10^23 molecules per mole)

= 0.664 moles

.664 moles x 28g/mol (as nitrogen is diatomic, 2x14g/mol) = 18.6 g = 0.0186kg

Then to get the force:

When the molecules hit the wall, I am assuming there is an instant acceleration in the opposite direction. thus;

F = ma

(0.0186kg)(350 m/s/s)

= 6.51 Newtons

Then, Pressure = F/A (Pascals)

(6.51N)/(0.0018m^2)

= 3616 Pascals.

This is the answer I obtained on my own, and with the help of a tutor and yet my assignment is saying it is wrong. Can you please shed some light on my mistake(s)?

Thank you!