A heater letting of heat is an example of release of energy. Please comment if you have any questions about my answer.<span />
According of Dalton's law of Partial pressure, the total pressure of a mixture of gases is the sum of the partial pressures of the individual vases in the mixture.
Hence;
The for hydrogen collected over water, we have a mixture of hydrogen gas and water vapour.
Total pressure = pressure of hydrogen gas + vapour pressure of water
Pressure of hydrogen gas = Total pressure - vapour pressure of water
Pressure of hydrogen gas = 636 mmHg - 28.3 mmHg
Pressure of hydrogen gas = 607.7 mmHg
<span>Use the Ideal law Equation :
P.V= n.R.T
V = 0.5 L
P = 1.0 atm
</span><span>R= 0.0821 L*atm/mol*K
</span>
<span>n = R*T/P*V
</span><span>P*V= n*R*T
</span>
1.0 * 0.5 = n *<span>0.0821*298
0,5 = n* 24.4658
n = 0,5 / 24.4658
n =0.0204 moles
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