<u>Answer:</u> The number of moles of nitrogen gas are 0.1043 moles and the pressure when volume and temperature has changed is 461.6 mmHg
<u>Explanation:</u>
To calculate the amount of nitrogen gas, we use the equation given by ideal gas which follows:

where,
P = pressure of the gas = 755 mmHg
V = Volume of the gas = 2.55 L
T = Temperature of the gas = ![23^oC=[23+273]K=296K](https://tex.z-dn.net/?f=23%5EoC%3D%5B23%2B273%5DK%3D296K)
R = Gas constant = 
n = number of moles of nitrogen gas = ?
Putting values in above equation, we get:

To calculate the pressure when temperature and volume has changed, we use the equation given by combined gas law.
The equation follows:

where,
are the initial pressure, volume and temperature of the gas
are the final pressure, volume and temperature of the gas
We are given:
![P_1=755mmHg\\V_1=2.55mL\\T_1=23^oC=[23+273]K=296K\\P_2=?\\V_2=4.10L\\T_2=18^oC=[18+273]K=291K](https://tex.z-dn.net/?f=P_1%3D755mmHg%5C%5CV_1%3D2.55mL%5C%5CT_1%3D23%5EoC%3D%5B23%2B273%5DK%3D296K%5C%5CP_2%3D%3F%5C%5CV_2%3D4.10L%5C%5CT_2%3D18%5EoC%3D%5B18%2B273%5DK%3D291K)
Putting values in above equation, we get:

Hence, the number of moles of nitrogen gas are 0.1043 moles and the pressure when volume and temperature has changed is 461.6 mmHg