Reno O. B. answered • 01/30/16

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1.

Total pressure=vapor pressure of water + gas pressure of sample.

425 torr=oxygen pressure + 22.377 torr

402.62 torr=gas pressure of oxygen.

Turn torr into atm: 402.62 torr*(1 atm/760 torr) or 0.52976 atm

Use PV=nRT equation to find mass of oxygen (solve for n)

P=0.52976 atm, V=1.335 L, T=273.15 + 24 K or 297.15 K, n=?

n=(PV)/(RT) or (0.52976atm*1.335L)/(0.08206 L-atm/mol-K*297.15K)

n=0.029 mole

2.

At STP, P=1 atm, T=273.15 K, V=?

Volume=Volume of Oxygen Gas + Volume of Argon Gas

V=(nRT)/P

moles of Oxygen=129 g/31.999 g per mole or 4.03 moles O2 gas.

moles of Argon=24 g/15.7596 g per mole or 1.52 moles Ar gas.

**add moles together**and plug into formula V=nRT/P

Volume=(

**4.03 + 1.52 moles**)*(0.08206 L-atm/mole-K)*273.15 K/1 atmVolume=124.4 mL