This is an incomplete question, here is a complete question.
If the initial concentration of NOBr is 0.0440 M, the concentration of NOBr after 9.0 seconds is ________.
The reaction
It is a second-order reaction with a rate constant of 0.80 M⁻¹s⁻¹ at 11 °C.
Answer : The concentration of after 9.0 seconds is, 0.00734 M
Explanation :
The integrated rate law equation for second order reaction follows:
![k=\frac{1}{t}\left (\frac{1}{[A]}-\frac{1}{[A]_o}\right)](https://tex.z-dn.net/?f=k%3D%5Cfrac%7B1%7D%7Bt%7D%5Cleft%20%28%5Cfrac%7B1%7D%7B%5BA%5D%7D-%5Cfrac%7B1%7D%7B%5BA%5D_o%7D%5Cright%29)
where,
k = rate constant = 0.80 M⁻¹s⁻¹
t = time taken = 142 second
[A] = concentration of substance after time 't' = ?
![[A]_o](https://tex.z-dn.net/?f=%5BA%5D_o)
= Initial concentration = 0.0440 M
Putting values in above equation, we get:
![0.80M^{-1}s^{-1}=\frac{1}{142s}\left (\frac{1}{[A]}-\frac{1}{(0.0440M)}\right)](https://tex.z-dn.net/?f=0.80M%5E%7B-1%7Ds%5E%7B-1%7D%3D%5Cfrac%7B1%7D%7B142s%7D%5Cleft%20%28%5Cfrac%7B1%7D%7B%5BA%5D%7D-%5Cfrac%7B1%7D%7B%280.0440M%29%7D%5Cright%29)
![[A]=0.00734M](https://tex.z-dn.net/?f=%5BA%5D%3D0.00734M)
Hence, the concentration of after 9.0 seconds is, 0.00734 M
After some thinking I have come to the conclusion that the answer is C.
We are asked to calculate the number of moles in a given mass of a substance. To be able to calculate it, we need the molar mass of the substance. For (NH4)2Cr2O7, the molar mass would be <span>252.07 g/mol. We calculate as follows:
0.025 g </span>(NH4)2Cr2O7 ( 1 mol / 252.07 g ) = 0.0001 mol <span>(NH4)2Cr2O7
Hope this answers the question. Have a nice day.</span>
Answer:
So, we rely on radiometric dating to calculate their ages. Radiometric dating, or radioactive dating as it is sometimes called, is a method used to date rocks and other objects based on the known decay rate of radioactive isotopes.
Explanation:
radiometric dating is a very accurate way to date the Earth.We know it is accurate because radiometric dating is based on the radioactive decay of unstable isotopes. When an unstable Uranium (U) isotope decays, it turns into an isotope of the element Lead (Pb).
Answer: 32.94 g
Explanation: It's stoichiometry problem so balanced equation is required. The balanced equation is given below:
From the balanced equation, krypton and chlorine react in 1:2 mol ratio. We will calculate the moles of each reactant gas using ideal gas law equation(PV = nRT) and then using mol ratio the limiting reactant is figured out that helps to calculate the amount of the product formed.
for Krypton, P = 0.500 atm and for chlorine, P = 1.50 atm
V = 15.0 L
T = 350.8 + 273 = 623.8 K
For krypton, 
n = 0.146 moles
for chlorine, 
n = 0.439
From the mole ratio, 1 mol of krypton reacts with 2 moles of chlorine. So 0.146 moles of krypton will react with 2 x 0.146 = 0.292 moles of chlorine.
Since 0.439 moles of chlorine are available, it is present in excess and hence the limiting reactant is krypton.
So, the amount of product formed is calculated from moles of krypton.
Molar mass of krypton tetrachloride is 225.61 gram per mol.
There is 1:1 mol ratio between krypton and krypton tetrachloride.
= 32.94 g of 
So, 32.94 g of the product will form.
