States of matter practice · Mixed difficulty

The correct answer is B because both statements are correct, but the inertness of helium doesn't explain its positive deviation from ideal behavior, which is due to its small size and weak intermolecular forces.

The correct answer is A (250 K) because the initial temperature is calculated using the relationship between pressure and temperature for a gas at constant volume.

Option C (Experimental observations) is correct because Gay-Lussac's law was formulated based on experimental data and observations of gas behavior under constant temperature and pressure.

Option C (Increase four fold) is correct because using the ideal gas law, when temperature doubles and pressure is halved, the volume increases by a factor of four.

Option B ($0.007\, \mathrm{~kg}\, \mathrm{~m}^{-3}$) is correct because it represents the difference in density between dry air and moist air calculated considering the partial pressure of water vapor.

Option A (If both assertion and reason are true and the reason is the correct explanation of the assertion) is correct because gases combine in simple ratios when they behave ideally, and deviations from ideal behavior explain why this isn't always the case.

Option D ($Z=\frac{p V_m}{R T}=1-\frac{a}{R T V_m}$) is correct because it represents the van der Waals equation at low pressure, where the volume is large and the 'b' term can be neglected.

Option D (Dipole-dipole interaction) is correct because the dipole-dipole interaction energy is inversely proportional to the cube of the distance between the molecules.

The correct answer is Linear with different slopes because the $P-T$ relationship is linear, and the slope depends on the volume.

Option D (Vapour pressure) is correct because vapor pressure increases with increasing temperature due to increased kinetic energy of molecules.

Option C (${\text{L}}{\text{.mo}}{{\text{l}}^{ - 1}}$) is correct because the van der Waals constant 'b' represents the volume per mole of gas molecules.

Option A (Volume occupied by the molecules) is correct because the van der Waals constant 'b' accounts for the finite volume of gas molecules.

Option A ($150 \mathrm{~K}$) is correct because the average speed of a gas is inversely proportional to the square root of its molar mass, and the temperature is adjusted accordingly.

Option B is correct because if there is no attraction between gas molecules, they will not come close enough to liquefy, even when cooled and compressed.

Option B ($20 \mathrm{~s}, \mathrm{O}_2$) is correct because the effusion rate is inversely proportional to the square root of the molar mass.

Option A ($\mathrm{H}_2$ and $\mathrm{Cl}_2$ mixture) is correct because hydrogen and chlorine react to form HCl under normal conditions, violating the assumption of non-reactivity in Dalton's law.

Option B ($65.97\,\,\mathrm{g}\,\mathrm{mo}{\mathrm{l}^{ - 1}}$) is correct because it is calculated using Graham's law of effusion, relating effusion rates to molar masses.

Option B ($\frac{1}{3}$) is correct because the partial pressure of a gas is proportional to its mole fraction in the mixture.

Option C (4) is correct because the pressure ratio is directly proportional to the ratio of densities and inversely proportional to the ratio of molecular weights, resulting in a ratio of 4.

Option C ($200\;\mathrm{K}$) is correct because it is derived from applying the ideal gas law under the given conditions of constant pressure and volume.

The correct answer is C because the assertion is correct (Z can be > 1) but the reason is incorrect (non-ideal gases can exert lower pressure than expected).

Option D (All of these) is correct because all the given expressions are valid representations of Kf, the cryoscopic constant.

Option D ($\frac{1}{{{r^3}}}$) is correct because the dipole-dipole interaction energy in solids is inversely proportional to the cube of the distance (radius) between the molecules.

Option C (When $T = 12K$) is correct because it satisfies the ideal gas law equation with the given conditions.

Option B (333.3 K) is correct because it is calculated using the ideal gas law with the given pressure, volume, and number of moles.

Option C (Same) is correct because the root mean square (rms) velocity depends only on temperature and molar mass, and since the temperature is constant, the rms velocity remains the same.

Option A (2050) is correct because the final pressure is the sum of the partial pressure of benzene and the compressed air pressure.

Option A (13.65 mL) is correct because it is calculated using Graham's law of diffusion, relating diffusion rate to molar mass.

Option B is correct because the kinetic molecular theory states that the velocity of gas molecules is proportional to their Kelvin temperature, explaining why a balloon collapses when exposed to liquid nitrogen.

Option A (If both A and R are correct and R is the correct explanation of A) is correct because the kinetic energy increase at higher temperatures allows more liquid molecules to overcome intermolecular forces and enter the vapor phase, thus increasing vapor pressure.