1L of a gas at STP weighs 1.97g. What is molecular mass?

Answer

To find the molecular mass of the gas, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the conditions**: We are given that 1 liter of gas at STP (Standard Temperature and Pressure) weighs 1.97 grams. At STP, 1 mole of an ideal gas occupies 22.4 liters.

2. **Set up the relationship**: Since we know that 1 mole of gas occupies 22.4 liters, we can find out how much 22.4 liters of the gas weighs by using the weight of 1 liter.

3. **Calculate the weight of 22.4 liters**:
\[ \text{Weight of 22.4 liters} = \text{Weight of 1 liter} \times 22.4 \]
\[ \text{Weight of 22.4 liters} = 1.97 \, \text{g} \times 22.4 \]

4. **Perform the multiplication**:
\[ \text{Weight of 22.4 liters} = 1.97 \times 22.4 = 44.088 \, \text{g} \]

5. **Round off the answer**: The molecular mass of the gas is approximately 44.1 grams.

### Final Answer:
The molecular mass of the gas is **44.1 grams**.

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