Final answer:
1 L of NO is heavier than 1 L of CO at STP because the molar mass of NO (30.01 g/mol) is greater than that of CO (28.01 g/mol); thus, the statement is true.
Step-by-step explanation:
The question asks whether 1 L of NO is heavier than 1 L of CO at STP (standard temperature and pressure). To determine this, we need to look at the molar masses of the two gases. Nitric oxide (NO) has a molar mass of approximately 30.01 g/mol, while carbon monoxide (CO) has a molar mass of 28.01 g/mol. At STP, one mole of any gas occupies approximately 22.4 liters. Therefore, at STP, one liter of each gas would contain a proportional fraction of one mole and will thus weigh proportionally to their molar mass.
Since 30.01 g/mol is heavier than 28.01 g/mol, 1 L of NO is indeed heavier than 1 L of CO at STP. The response to this true or false question is true.