<u>Answer:</u> The number of moles of nitrogen gas is 0.030 moles
<u>Explanation:</u>
To calculate the number of moles of nitrogen, we use the equation given by ideal gas which follows:

where,
P = pressure of the nitrogen gas = 2.96 atm
V = Volume of the gas = 0.25 L
T = Temperature of the gas = 300 K
R = Gas constant = 
n = number of moles of nitrogen gas = ?
Putting values in above equation, we get:

Hence, the number of moles of nitrogen gas is 0.030 moles
The coordination number is 6. The outer Cl- ion isn't included, so you count 4 x NH3 and 2 x Cl- are within Co's coordination sphere.
<u>Answer: </u>The correct rate of the reaction is ![Rate=k[a][b]^5[c]^6](https://tex.z-dn.net/?f=Rate%3Dk%5Ba%5D%5Bb%5D%5E5%5Bc%5D%5E6)
<u>Explanation:</u>
Rate law of the reaction is the expression which expresses the rate of the reaction in the terms of the molar concentrations of the reactants with each term raised to the power of their respective stoichiometric coefficients in a balanced chemical equation.
For the given reaction:

The expression for the rate law will be: ![Rate=k[a][b]^5[c]^6](https://tex.z-dn.net/?f=Rate%3Dk%5Ba%5D%5Bb%5D%5E5%5Bc%5D%5E6)
The answer is 70 I guess. Hope this helps :)
It would be 10kg, because 1kg = 10N