10 mL of hydrogen contains 2 x 10^3 molecules of hydrogen at a certain pressure and temperature. Calculate the number of molecules of oxygen whose volume is 200 mL at the same temperature and pressure:
Correct answer: B. 4 x 10^4 molecules
- A. 2 x 10^4 molecules
- B. 4 x 10^4 molecules
- C. 4 x 10^2 molecules
- D. None of these options are correct
Explanation
At the same temperature and pressure, equal volume of the gas contains equal number of molecules. Hence, 10 ml of H2 or O2 = 2 x 103 number of molecules 200 ml of H2 or O2 = (2 x 103 / 10) x 200. =4 X 104 number of molecules.
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