States of Matter Gases & Liquids Quiz - ICSE Class 11 Chemistry
Free practice quiz: States of Matter Gases & Liquids (ICSE Class 11 Chemistry). 51 multiple-choice questions with answers and explanations. Play online, no sign-up needed.
Play all 51 questions freeSample questions
According to the kinetic theory of gases, at absolute zero temperature, the kinetic energy of gas molecules is:
- Maximum
- Minimum but not zero
- Zero
- Dependent on the pressure
Show answer
Answer: C. Zero
The kinetic theory of gases states that the average kinetic energy of gas molecules is directly proportional to the absolute temperature. At absolute zero (0 Kelvin), the molecular motion ceases, and therefore, the kinetic energy is zero.
Which of the following gas laws states that at constant volume, the pressure of a fixed amount of gas is directly proportional to its absolute temperature?
- Boyle's Law
- Charles's Law
- Gay-Lussac's Law
- Avogadro's Law
Show answer
Answer: C. Gay-Lussac's Law
Gay-Lussac's Law (also known as the pressure law) states that for a fixed mass of gas at constant volume, the pressure is directly proportional to the absolute temperature (P $\propto$ T). Boyle's Law relates pressure and volume at constant temperature (P $\propto$ 1/V). Charles's Law relates volume and temperature at constant pressure (V $\propto$ T). Avogadro's Law relates volume and the number of moles at constant temperature and pressure (V $\propto$ n).
A liquid will boil at a temperature lower than its standard boiling point when:
- The external pressure is increased
- The external pressure is decreased
- The liquid is heated rapidly
- The liquid is allowed to cool
Show answer
Answer: B. The external pressure is decreased
Boiling occurs when the vapor pressure of the liquid equals the external pressure. If the external pressure is lowered, the liquid will reach its boiling point at a lower temperature because its vapor pressure will equal the lower external pressure sooner.
Which of the following liquids would have the highest surface tension at room temperature?
- Water
- Ethanol
- Acetone
- Benzene
Show answer
Answer: A. Water
Water exhibits strong hydrogen bonding between its molecules, leading to significant cohesive forces and thus high surface tension. Ethanol also has hydrogen bonding but to a lesser extent. Acetone and benzene have weaker dipole-dipole interactions and London dispersion forces, resulting in lower surface tensions.
If the pressure on a gas is doubled and its absolute temperature is also doubled, the volume of the gas will:
- Remain the same
- Be doubled
- Be halved
- Be quadrupled
Show answer
Answer: A. Remain the same
From the combined gas law, (P1 * V1) / T1 = (P2 * V2) / T2. Let P2 = 2*P1 and T2 = 2*T1. Then (P1 * V1) / T1 = (2*P1 * V2) / (2*T1). Simplifying, V1 = V2. The volume remains the same.