Answer:
Initially
of nitrogen dioxide were in the container .
Step-by-step explanation:
Volume of the container at low pressure and at room temperature =
![V_1=3.4 L](https://img.qammunity.org/2020/formulas/chemistry/college/8yj371aspwfmqsmp2xc3599n0x3bedgrd4.png)
Number of moles in the container =
![n_1](https://img.qammunity.org/2020/formulas/physics/high-school/3z87dv3vk94focl6co6jwh9fz86asy71af.png)
After more addition of nitrogen gas at the same pressure and temperature.
Volume of the container after addition =
![V_2=5.11 L](https://img.qammunity.org/2020/formulas/chemistry/college/qo5j3g8b1jotrddtmvaxjpnq0d88lfwxa2.png)
Number of moles in the container after addition=
![n_2=2.28* 10^(-2) mol](https://img.qammunity.org/2020/formulas/chemistry/college/mzrv2lgw8ogftuyvf5jsfa4676g5d9mjcp.png)
Applying Avogadro's law:
(at constant pressure and temperature)
![(V_1)/(n_1)=(V_2)/(n_2)](https://img.qammunity.org/2020/formulas/chemistry/college/z152qk8l3uj312z80sy4hxwwy7d32l4kfh.png)
![n_1=(V_1* n_2)/(V_2)=(3.4 L* 2.28* 10^(-2) mol)/(5.11 L)](https://img.qammunity.org/2020/formulas/chemistry/college/b7hg7d4187okcnx9hu92kby850sgzixa85.png)
![n_1=1.51* 10^(-2) mol](https://img.qammunity.org/2020/formulas/chemistry/college/ecngtyznyi6sllkwqmyqzk56y745dkx4ex.png)
Initially
of nitrogen dioxide were in the container .