Final answer:
To calculate the mass of chlorine gas in grams given a volume of 7.50 liters at STP, we use the volume-to-moles relationship for gases at STP and the molar mass of chlorine gas. After finding the number of moles, we multiply it by the molar mass of Cl2 to get the mass, which is approximately 23.75 grams, making 22.4 grams the closest answer choice.
Step-by-step explanation:
The question is asking to calculate the mass of chlorine gas (Cl2) in grams, given a volume of 7.50 liters at Standard Temperature and Pressure (STP). At STP, one mole of any gas occupies 22.4 liters. The molar mass of chlorine gas is 70.90 grams per mole, which can be calculated from the atomic mass of chlorine (35.45 grams per mole for one chlorine atom, thus 70.90 grams for diatomic chlorine, Cl2).
To find the mass, we first calculate the number of moles of Cl2 gas using the given volume and then convert the moles to grams using the molar mass:
- Number of moles of Cl2 = Volume (Liters) / Volume of one mole at STP (Liters)
- Number of moles of Cl2 = 7.50 L / 22.4 L/mol
- Number of moles of Cl2 "<= 0.335 mol (approximately)"
- Mass of Cl2 = Number of moles * Molar mass of Cl2
- Mass of Cl2 = 0.335 mol * 70.90 g/mol
- Mass of Cl2 = 23.75 grams
Therefore, the closest answer choice is B. 22.4 grams.