Help! AP Chem

Test Preparation AP Test Preparation
1

<p>I have a test on Thermo/Gases tomorow and need help on these two problems:</p>

<p>1.Calculate the molecular mass of a volatile liquid
The only example our teacher gave was one we did in a lab, but I'm confused and my lab partner is..unhelpful. The data we had:
Temperature of vapor:375 K
Pressure of vapor: 1 atm
Volume of Flask: 231 ml (g of water)
Temperature of H20 in flask: 25 C
Density of water: 1</p>

<p>I know you have to get the moles of vapor in flask..but..um.. (There is a lot more data, but I don't know if it is relevant) And also, how do you find the density of the vapor?? </p>

<p>2.determine specific heat of a metal (put metal in bioling water--> calorimeter)
given:
mass of metal: 69.12
change in T of metal: 76.2 C
mass of water: 125 g
change in T of water: 4.2 C</p>

<p>is this a MC(delta)T=MC(delta)T problem? </p>

<p>Thanks for any help!</p>

2

<ol>
<li><p>yeah it is</p></li>
<li><p>density = mass/volume, i don't remember the stuff about volatile liquids, but shouldn't the lab tell you what to do? There are usually instructions given and stuff regarding calculations are also given to you on the lab procedures.</p></li>
</ol>

3

<p>mpph can't find the lab..going to start looking again.. Thanks!</p>

4

<p>Found lab! <em>is triumphant</em> Turns out you do PV=nRT to get the moles and then do g/mol to get the molec weight..still don't know about density though..I guess you would put the g/L in flask..hmm</p>

5

<p>yeah perhaps that's it</p>