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# Calculate the molar mass of the unknown gas.?

The mass of an evacuated 260 mL flask is 143.207 g . The mass of the flask filled with 276 torr of an unknown gas at 35 ∘C is 144.207 g .

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- hcbiochemLv 71 month ago
Use the ideal gas law to calculate the moles of gas in the flask:

PV = n RT

P = 276 torr/760 torr/atm = 0.363 atm

T = 35 + 273 = 308 K

0.363 atm (0.260 L) = n (0.08206 Latm/molK) (308 K)

n = 3.74X10^-3 mol gas

Molar mass = 1.000 g / 3.74X10^-3 mol = 268 g/mol

- Anonymous1 month ago
move to homework help. CHEATER.

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