Final answer:
The molecular weight of a gas, where 250 mL at STP has a mass of 1.00 g, is calculated by using the molar volume of a gas at STP, which is 22.4 L/mol. Upon conversion and calculating the number of moles, the molecular weight is found to be approximately 89.6 g/mol, corresponding to answer choice a) 89.6.
Step-by-step explanation:
To calculate the molecular weight of the gas given that 250 mL of gas at STP has a mass of 1.00 g, we can use the fact that the molar volume of a gas at STP (Standard Temperature and Pressure) is 22.4 L/mol.
This means at STP, 1 mole of a gas occupies 22.4 liters. First, we convert the volume from milliliters to liters by dividing by 1000, so 250 mL becomes 0.250 L.
Since 1 mole takes up 22.4 liters, we can calculate how many moles are in 0.250 liters using the proportion:
Number of moles = 0.250 L ÷ 22.4 L/mol
Using the mass of the gas (1.00 g) and the number of moles we just found, we can solve for the molecular weight (MW):
MW = mass ÷ number of moles
However, it seems that there was a minor miscalculation in the provided strategy section. If we properly calculate the number of moles and the corresponding molecular weight, we find that:
Number of moles = 0.250 L / 22.4 L/mol = 0.01116 mol (approximately)
MW = 1.00 g / 0.01116 mol = 89.6 g/mol (approximately)
Therefore, the correct answer would be: a) 89.6