Question

Avogadro’s hypothesis relates volume of gases and:

• A. mass
• B. temperature
• C. pressure
• D. number of molecules

Hint:

Avogadro’s law links the volume of a gas with the number of molecules, provided the temperature and pressure are constant.

Answer 1

The Correct Option is D

Step 1: Concept.
Avogadro's hypothesis states that at constant temperature and pressure, equal volumes of any gas contain equal numbers of molecules, written as volume is proportional to the number of molecules.

Step 2: Check the options.
Temperature and pressure are the fixed conditions in this statement, not the variable being linked to volume, and mass does not appear in the relationship at all.

Step 3: Final Answer.
Avogadro's hypothesis relates the volume of gases to the Number of molecules.

Answer 2

Picturing two identical balloons filled with two different gases under the same conditions makes this relationship concrete.

1. Mass: Fill one balloon with hydrogen and an identical one with carbon dioxide, both at the same temperature, pressure, and volume, and the two balloons will weigh very differently, since mass depends on which gas is inside, not on the volume alone.
2. Temperature: Both balloons are kept at the same temperature in this comparison, so temperature is a condition being held steady, not something volume is being related to here.
3. Pressure: Both balloons are also kept at the same pressure, so pressure, too, is a fixed background condition for this comparison, not the quantity of interest.
4. Number of molecules: Despite the mass difference, Avogadro's hypothesis says both identical balloons, filled to the same volume at the same temperature and pressure, contain exactly the same number of gas molecules, regardless of which gas is used.

Two identical balloons with different gases can differ hugely in mass yet still hold the same number of molecules, exactly matching what Avogadro's hypothesis predicts about volume and molecule count.

So the correct answer is Number of molecules.