Let's write the equation

According to law of conservation of mass .
- Mass of products=Mass of reactants
Let required value be x




0.091 moles are contained in 2.0 L of N2 at standard temperature and pressure.
Explanation:
Data given:
volume of the nitrogen gas = 2 litres
Standard temperature = 273 K
Standard pressure = 1 atm
number of moles =?
R (gas constant) = 0.08201 L atm/mole K
Assuming nitrogen to be an ideal gas at STP, we will use Ideal Gas law
PV = nRT
rearranging the equation to calculate number of moles:
PV = nRT
n = 
putting the values in the equation:
n = 
n = 0.091 moles
0.091 moles of nitrogen gas is contained in a container at STP.
We shall consider V, the volume and T, the temperature.
According to Boyle's Laws:

In our case:
Answer:
The volume of NO₂ gas collected over water at 25.0 °C is 1.68 Liters.
Explanation:

Moles of copper = 
According to reaction, 1 mol of copper gives 2 moles of nitrogen dioxide gas.
Then 0.03613 moles of copper will give:
of nitrogen dioxide gas
Moles of nitrogen dioxide gas = n = 0.06326 mol
Pressure of the gas = P
P = Total pressure - vapor pressure of water
P = 726 mmHg - 23.8 mmHg = 702.2 mmHg
P = 0.924 atm (1 atm = 760 mmHg)
Temperature of the gas = T = 25.0°C =298.15 K
Volume of the gas = V


V = 1.68 L
The volume of NO₂ gas collected over water at 25.0 °C is 1.68 Liters.