According to the kinetic molecular theory, how do gas molecules move?
Correct answer A. Randomly in straight lines until they collide
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MDCAT ECAT Chemistry MCQs
Page 12 of MDCAT ECAT Chemistry multiple-choice questions with answers. Tap an option to check yourself.
Page 12 of 39
- Gases 40
- Liquids 40
- Solids 40
- Chemical Equilibrium 40
- Reaction Kinetics 40
- Thermochemistry and Energetics 40
- Electrochemistry 40
- Fundamental Concepts of Chemistry 40
- Atomic Structure 39
- Chemical Bonding 39
- Alcohols and Phenols 38
- Industrial Chemistry 37
- Aldehydes and Ketones 37
- Alkyl Halides 37
- s- and p-Block Elements 37
- Chemistry of Hydrocarbons 36
- Fundamental Principles of Organic Chemistry 36
- Carboxylic Acids 36
- Transition Elements 35
- Macromolecules 35
For a fixed mass of gas at constant temperature, which plot gives a straight line passing through the origin?
Correct answer A. P against 1/V
Which expression represents Charles’s law for a fixed mass of gas at constant pressure?
Correct answer D. V/T = constant
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How do Boyle’s law isotherms (P against V curves) change as the temperature of the gas is raised?
Correct answer C. They move further away from the axes
A gas at 0 °C is heated at constant pressure until its volume doubles. What is its final temperature?
Correct answer A. 273 °C
0.64 g of a gas occupies 224 cm³ at STP. What is its molar mass?
Correct answer B. 64 g mol⁻¹
What is the density of carbon dioxide at STP (C = 12, O = 16; molar volume = 22.4 dm³)?
Correct answer A. 1.96 g dm⁻³
About how many molecules are present in 1 cm³ of an ideal gas at STP?
Correct answer C. 2.69 × 10¹⁹
In the van der Waals equation, the constant b is related to ____
Correct answer D. the actual volume occupied by the gas molecules
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Which gas is expected to show the greatest deviation from ideal behaviour at room temperature?
Correct answer C. NH₃
For a real gas at moderate pressure, the compressibility factor Z is less than 1. What does this indicate?
Correct answer A. Attractive forces between molecules dominate
At the same temperature, how does the average kinetic energy of H₂ molecules compare with that of O₂ molecules?
Correct answer A. It is the same
Using average kinetic energy = (3/2)RT per mole, what is the translational kinetic energy of 1 mol of gas at 300 K (R = 8.314 J K⁻¹ mol⁻¹)?
Correct answer B. 3.74 kJ
Why are gases much more compressible than liquids and solids?
Correct answer A. There are large empty spaces between gas molecules
A sealed rigid container holds a gas at 1.0 atm and 27 °C. What is its pressure when heated to 327 °C?
Correct answer A. 2.0 atm
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Why are liquids almost incompressible?
Correct answer D. Their molecules are already very close together
How does the viscosity of a liquid change when its temperature is raised?
Correct answer A. It decreases
Why is glycerol much more viscous than water?
Correct answer D. Each molecule has three –OH groups that form extensive hydrogen bonds
Which liquid has the lowest boiling point?
Correct answer C. Diethyl ether
Why is glycerol purified by distillation under reduced pressure?
Correct answer B. It decomposes at its normal boiling point, and lower pressure lowers the boiling point