# How to calculate mass using PV=nRT equation

Naphthalene, C10H8, is the substance present in some moth balls. Its vapor pressure at 25° is 0.300mmHg

a. how many milligrams f naphthalene will sublime into an evacuated 1.000-L flask?

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At 25

^{o}C, solid naphthalene will be in equilibrium with its vapor, which will be at a pressure of 0.300 mmHg.You have

PV = nRT

T = 298 K

P = 0.300 mmHg

V= 1.00 L

If you find R with matching units (or convert units as needed) you can solve for the number of moles, n.

You can convert number of moles to mass, by using the fact that 1 mole of C

_{10}H_{8}should have a mass of 128.2 grams.(10 x 12.01 + 8 x 1.01 = 128.2)

KMST

Mon, 2011-06-13 16:32