Answer:
The pressure exerted by the final gas is 18.1 kPa
Step-by-step explanation:
We note that according to Dalton's law of partial pressure, the pressure a=exerted by a mixture of gases is equal to the sum of the partial pressures of the individual gases in the mixture
The gases and their partial pressures are;
Hydrogen = 40.8 kPa
Bromine = 26.7 kPa
Fluorine = 3.5 kPa
Helium = 12.7 kPa
Final gas pressure = required
Therefore,
40.8 + 26.7 + 3.5 + 12.7 + Final gas pressure = 101.8 kPa
83.7 kPa + Final gas pressure = 101.8 kPa
Final gas pressure = 101.8 kPa - 83.7 kPa = 18.1 kPa
The pressure exerted by the final gas = 18.1 kPa.