Question

Number of moles and number of molecules in 1.4187 L of SO₂ at STP respectively are

• A. 0.1266; \(3.812 \times 10^{22}\)
• B. 0.0633; \(3.812 \times 10^{22}\)
• C. 0.1266; \(7.6238 \times 10^{22}\)
• D. 0.0633; \(7.6238 \times 10^{22}\)

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
At Standard Temperature and Pressure (STP), 1 mole of any ideal gas occupies a volume of 22.4 L. To find the number of moles, we divide the given volume by the molar volume. To find the number of molecules, we multiply the number of moles by Avogadro's number (\(N_A \approx 6.022 \times 10^{23}\)).

Step 2: Key Formula or Approach:
1. Number of moles (\(n\)) = \(\frac{\text{Volume at STP}}{\text{Molar Volume (22.4 L)}}\) 2. Number of molecules = \(n \times N_A\)

Step 3: Detailed Explanation:
1. Calculate moles of \(SO_2\): \[ n = \frac{1.4187 \text{ L}}{22.4 \text{ L/mol}} \approx 0.06333 \text{ mol} \] 2. Calculate molecules: \[ \text{Molecules} = 0.06333 \times 6.022 \times 10^{23} \] \[ \text{Molecules} \approx 3.813 \times 10^{22} \]

Step 4: Final Answer:
The number of moles is approximately 0.0633 and the number of molecules is \(3.812 \times 10^{22}\).