Chem Question from 1998 administration

Test Preparation SAT Subject Test Preparation
1

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<ol>
<li>(Shows a picture of two circles: one circle-1 liter of H2 and the second circle-2 liters of Gas X)
Both the gas samples represented above are at the same temperature and pressure. The mass of H2 in the one-liter container is .20 gram. The mass of X in the two-liter contaiter in 8 grams. The molecular weight of X is:
(A) 10
(B) 20
(C) 40
(D) 60
(E) 80</li>
</ol>

<p>EDIT: Wow. just figured this out. 2 liters of H2 is .4g. Then you just set up a proportion</p>

<p>(.4g)/(2GFM)=8/x
x=40
(C)
lol how could I omit this</p>

2

<p>how did you do #69 in the 1998 administration ???</p>

3

<p>@firas1234</p>

<p>since you know 2 moles of NO release 150 kJ of energy, you could set up a proportion</p>

<p>2/150 = 0.8/x
2x=150*8
x=60</p>

<p>answer is D</p>