<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 initial pressure, volume and temperature of the gas
 are the final 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