Question #73fe8

1 Answer
Nov 26, 2015

The volume of the gas at STP is 7.58 L.

Explanation:

Use the ideal gas law, PV=nRTPV=nRT, where nn is moles and RR is the gas constant.

Convert molecules to moles by dividing by (6.022xx10^23"molecules")/(1"mol")6.022×1023molecules1mol.

2.01xx10^23"molecules"xx(1"mol")/(6.022xx10^23"molecules")="0.33378 mol"2.01×1023molecules×1mol6.022×1023molecules=0.33378 mol

(I am keeping a couple of guard digits to reduce rounding errors.)

"STP"STP is "273.15 K"273.15 K and "100 kPa"100 kPa.

Given/Known
P="100 kPa"P=100 kPa
n="0.33378 mol"n=0.33378 mol
R="8.3144598 L kPa K"^(-1) "mol"^(-1)"R=8.3144598 L kPa K1mol1
https://en.m.wikipedia.org/wiki/Gas_constant
T="273.15 K"T=273.15 K

Unknown
VV

Equation
PV=nRTPV=nRT

Solution
Rearrange the equation so that VV is isolated and solve.

V=(nRT)/PV=nRTP

V=(0.33378cancel"mol"xx8.3144598 "L" cancel"kPa" cancel("K"^(-1)) cancel("mol"^(-1))xx273.15cancel"K")/(100 cancel"kPa")="7.58 L"