<u>Answer:</u> The rate law expression for the given reaction is written below.
<u>Explanation:</u>
Rate law is defined as the expression which expresses the rate of the reaction in terms of molar concentration of the reactants with each term raised to the power their stoichiometric coefficient of that reactant in the balanced chemical equation.
For the given chemical equation:

Rate law expression for the reaction:
![\text{Rate}=k[NO]^2[H_2]^2](https://tex.z-dn.net/?f=%5Ctext%7BRate%7D%3Dk%5BNO%5D%5E2%5BH_2%5D%5E2)
Hence, the rate law expression for the given reaction is written above.
Answer:

Explanation:
= First mass of water = 12 oz
= Second mass of water = 20 oz
= Temperature difference of the solution with respect to the first mass of water =
= Temperature difference of the solution with respect to the second mass of water = 
c = Specific heat of water
As heat gain and loss in the system is equal we have

The final temperature of the solution is
.
Answer:
78.7
Explanation:
The number has 4 significant figures: 7,8 6 and 5.
To round off to 3 significant figures, the target digit is the third significant figure in the number.The determining digit is the fourth significant figure in the number; it is 5 hence the target digit will go up by 1 and any digits to the right of it will be rounded down to 0.