Thermal concepts questions (chem related)

[yamugushi]

I know these aren't exactly physics problems but I'm being asked them in physics so...

Homework Statement

1) As lead melts there is a change in it's...
Temperature
Heat of fusion (what I now think it is)
Avg molecular KE (what I thought it was)
Avg molecular PE

2)In a room there is 250kg of air, in the avg molecular mass of air is 28.8g/mol (.0288kg) how many particles of "air" is in the room?

Homework Equations

1) none

2) n=m/M

The Attempt at a Solution

1) look above in parentheses

2)
n=250/.028
8860.55

 

[ideasrule]

Your answers to #1 are wrong. Check your textbook for an explanation of the heat of fusion. I can explain it here, but it's too important a concept to cover thoroughly in one forum post.

For #2, you found the number of moles. The question asks for the number of actual particles.