Five liters of gas at STP have a mass of 12.5 g. What is the molecular mass of the gas?
A. 12.5 g/mol
B. 25.0 g/mol
C. 47.5 g/mol
D. 56.0 g/mol
E. 125 g/mol
Answer (2)
You have 12.5 grams. And 5 liters of some random gas.
Step 1: You must find the mol amount of that 12.5g mass.
12.5 / 5 = 2.5 mol
Step 2: Now find the molecular mass of that gas "at STP" (STP- is 22.4 L)
2.5 x 22.4 = 56 g/mol
Good Luck on Chemistry SAT, cause I know exactly where you got this question from.
The molecular mass of the gas is approximately 56.0 g/mol, calculated using the mass and volume of the gas at STP. The number of moles is derived from the volume, and the molecular mass is found by dividing the mass by this number of moles. Therefore, the correct answer is D. 56.0 g/mol.
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