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Dalton's Law chem questions. Help, please?

1) 100 ml of hydrogen are measured over water at 16 C and 744 torrs. Calculate the volume when dry and at STP

2) Hydrogen gas and helium exert a combined pressure of 4.5 atm. If hydrogen's partial pressure is 150 kPA, what is the pressure of the He. gas?

3) 300 mL of H2 and 200 mL of F2 exert a total pressure of 1500 mmHg. What is the PH2 and PF2?

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Could somebody please explain HOW to go about such problems?

2 Answers

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  • 1 decade ago
    Favorite Answer

    1) Collected over water so the pressure must be reduced by the vapor pressure of water at 16 deg C (13.6 mm Hg)

    P = 744 mm Hg - 13.6 mm Hg = 730 mm Hg = 0.9605 atm

    V = 0.100 L

    n = PV/RT = 0.9605 x 0.100 / (0.08206 x 289)

    n = 0.00405 moles of H2

    1 mole at STP = 22.4 L

    0.00405 moles at STP = 22.4 L x 0.00405 = 0.0907 L

    H2 volume at STP = 90.7 mL

  • 4 years ago

    this question makes use of boyle's regulation it extremely is P1V1=P2V2 a million) handle the counsel you have P1= a million.08 atm V1=5.00 L P2= ? v2= 10.0 L 2) plug those into the boyle's regulation formulation (a million.08 atm) (5.00 L) = (P2)(10.0 L) 3) multiply and remedy to your answer: a million.08 x 5.00 = 5.4, divide 5.4 through 10.0L which equals 0.fifty 4 P2= 0.fifty 4 is your very final answer different gas regulations are: charles regulation - V1/T1= V2/T2 (quantity over temperature) gay-lussac - P1/T1=P2/T2 (tension over temperature) perfect gas - PV=nRT (P=tension. V=quantity, n=form of moles of gas, R= gas consistent), T=temperature

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