Chapter U3, Problem SIII3RE

Interpretation Introduction

Interpretation: The false statement for 22.4 L of Helium and 22.4 L of Neon gas at STP needs to be determined.

Concept Introduction: The ideal gas equation exhibits the relation between pressure, volume and temperature. The ideal gas equation can be written as:

  $\begin{array}{l}\text{PV = nRT}\\ \text{P = pressure }\\ \text{V = volume }\\ \text{n = number of moles }\\ \text{R = gas constant }\\ \text{T = temperature}\end{array}$

Answer to Problem SIII3RE

Correct answer: Option (D)

Explanation of Solution

Reason for correct option: At STP; the volume of 1 mole of gas is always 22.4 L. At STP; 22.4 L of He and Ne must contain 1 mole of gas. Although the molar mass of He and Ne gases are different yet the moles of both gases will remain same. The number density, n/V must be same for both sample as number of moles and volume are same for both gases at STP.

Conclusion

Reasons for incorrect options: The statement that two samples have the same mass density, D must be false because density is ratio of mass and volume. The mass of both gases are different as molar mass of He is 4 amu whereas molar mass of Ne is 20 amu. Therefore, density must be different for both gases.