Answer:
627mL (May be something is wrong with the choices)
Explanation:
First step: Ideal gas Law to get the moles
P . V = n . R . T
where P is pressure in atm (638.7 mmHg)
V is volume in L
n, the number of moles, the unknow value at this time
R the Ideal gas constant 0.082 L.atm/mol.K
T, the temperature in K (°C + 273)
760 mmHg ___ 1 atm
638.7 mmHg ___ (638.7 /760) = 0.84 atm
771,8 mL / 1000 = 0.7718 L
6.5°C + 273 = 279.5 K
0.7718 L . 0.84atm = n. 0.082 L.atm/mol.K . 279.5K
0.7718 L . 0.84atm /0.082 mol.K/L.atm . 279.5K = n
0,028 moles = n
Standard temperature and pressure are 273K and 1 atm
1 atm . Volume = 0,028 moles . 0.082 L.atm/mol.K . 273K
Volume = (0,028 moles . 0.082 L.atm/mol.K . 273K) /1atm
Volume = 0,6268 L = 627mL
