Question

How many molecules are present in 11.2 L of \(CO_{2}\) at STP?

• A. \(6.022 \times 10^{22}\)
• B. \(3.011 \times 10^{23}\)
• C. \(6.022 \times 10^{23}\)
• D. \(3.011 \times 10^{22}\)

Hint:

Remember that 1 mole of any gas at STP occupies 22.4 L and contains \(6.022 \times 10^{23}\) molecules. Use simple proportions to solve such questions.

Answer 1

The Correct Option is B

Step 1: At STP (Standard Temperature and Pressure), 1 mole of any ideal gas occupies 22.4 L. 
Step 2: Therefore, the number of moles in 11.2 L of \(CO_{2}\)} is: \[ \text{Moles} = \frac{11.2}{22.4} = 0.5 \text{ mol} \] Step 3: 1 mole contains \(6.022 \times 10^{23}\) molecules (Avogadro’s number). So, \[ \text{Number of molecules} = 0.5 \times 6.022 \times 10^{23} = 3.011 \times 10^{23} \]