Answer:
Option C. 52.057
Explanation:
The following data were obtained from the question:
Isotope >> Mass number > Percentage
A (Cr-50) > 50 >>>>>>>>>> 4.3
B (Cr-52) > 52 >>>>>>>>>> 83.8
C (Cr-53) > 53 >>>>>>>>>> 9.5
D (Cr-54) > 54 >>>>>>>>>> 2.4
Average atomic mass =?
The average atomic mass of chromium, Cr can be obtained as follow:
Average atomic mass = [(Mass of A × A%) /100] + [(Mass of B × B%) /100] + [(Mass of C × C%) /100] + [(Mass of D × D%) /100]
Atomic mass of Cr = [50×4.3)/100] + [52×83.8)/100] + [53×9.5)/100] + [54×2.4)/100]
= 2.15 + 43.576 + 5.035 + 1.296
Atomic mass of Cr = 52.057
Therefore, the atomic mass of chromium, Cr is 52.057
Answer:
ai) Rate law, ![Rate = k [CH_3 Cl] [Cl_2]^{0.5}](https://tex.z-dn.net/?f=Rate%20%3D%20k%20%5BCH_3%20Cl%5D%20%5BCl_2%5D%5E%7B0.5%7D)
aii) Rate constant, k = 1.25
b) Overall order of reaction = 1.5
Explanation:
Equation of Reaction:

If
, the rate of backward reaction is given by:
![Rate = k [A]^{a} [B]^{b}\\k = \frac{Rate}{ [A]^{a} [B]^{b}}\\k = \frac{Rate}{ [CH_3 Cl]^{a} [Cl_2]^{b}}](https://tex.z-dn.net/?f=Rate%20%3D%20k%20%5BA%5D%5E%7Ba%7D%20%5BB%5D%5E%7Bb%7D%5C%5Ck%20%3D%20%5Cfrac%7BRate%7D%7B%20%5BA%5D%5E%7Ba%7D%20%5BB%5D%5E%7Bb%7D%7D%5C%5Ck%20%3D%20%5Cfrac%7BRate%7D%7B%20%5BCH_3%20Cl%5D%5E%7Ba%7D%20%5BCl_2%5D%5E%7Bb%7D%7D)
k is constant for all the stages
Using the information provided in lines 1 and 2 of the table:
![0.014 / [0.05]^a [0.05]^b = 00.029/ [0.100]^a [0.05]^b\\0.014 / [0.05]^a [0.05]^b = 00.029/ [2*0.05]^a [0.05]^b\\0.014 / = 0.029/ 2^a\\2^a = 2.07\\a = 1](https://tex.z-dn.net/?f=0.014%20%2F%20%5B0.05%5D%5Ea%20%5B0.05%5D%5Eb%20%3D%2000.029%2F%20%5B0.100%5D%5Ea%20%5B0.05%5D%5Eb%5C%5C0.014%20%2F%20%5B0.05%5D%5Ea%20%5B0.05%5D%5Eb%20%3D%2000.029%2F%20%5B2%2A0.05%5D%5Ea%20%5B0.05%5D%5Eb%5C%5C0.014%20%2F%20%3D%200.029%2F%202%5Ea%5C%5C2%5Ea%20%3D%202.07%5C%5Ca%20%3D%201)
Using the information provided in lines 3 and 4 of the table and insering the value of a:
![0.041 / [0.100]^a [0.100]^b = 0.115 / [0.200]^a [0.200]^b\\0.041 / [0.100]^a [0.100]^b = 0.115 / [2 * 0.100]^a [2 * 0.100]^b\\](https://tex.z-dn.net/?f=0.041%20%2F%20%5B0.100%5D%5Ea%20%5B0.100%5D%5Eb%20%3D%200.115%20%2F%20%5B0.200%5D%5Ea%20%5B0.200%5D%5Eb%5C%5C0.041%20%2F%20%5B0.100%5D%5Ea%20%5B0.100%5D%5Eb%20%3D%200.115%20%2F%20%5B2%20%2A%200.100%5D%5Ea%20%5B2%20%2A%200.100%5D%5Eb%5C%5C)
![0.041 = 0.115 / [2 ]^a [2]^b\\ \[[2 ]^a [2]^b = 0.115/0.041\\ \[[2 ]^a [2]^b = 2.80\\\[[2 ]^1 [2]^b = 2.80\\\[[2]^b = 1.40\\b = \frac{ln 1.4}{ln 2} \\b = 0.5](https://tex.z-dn.net/?f=0.041%20%3D%200.115%20%2F%20%5B2%20%5D%5Ea%20%5B2%5D%5Eb%5C%5C%20%5C%5B%5B2%20%5D%5Ea%20%5B2%5D%5Eb%20%3D%200.115%2F0.041%5C%5C%20%5C%5B%5B2%20%5D%5Ea%20%5B2%5D%5Eb%20%3D%202.80%5C%5C%5C%5B%5B2%20%5D%5E1%20%5B2%5D%5Eb%20%3D%202.80%5C%5C%5C%5B%5B2%5D%5Eb%20%3D%201.40%5C%5Cb%20%3D%20%5Cfrac%7Bln%201.4%7D%7Bln%202%7D%20%5C%5Cb%20%3D%200.5)
The rate law is: ![Rate = k [CH_3 Cl] [Cl_2]^{0.5}](https://tex.z-dn.net/?f=Rate%20%3D%20k%20%5BCH_3%20Cl%5D%20%5BCl_2%5D%5E%7B0.5%7D)
The rate constant
then becomes:
![k = 0.014 / ( [0.050] [0.050]^(0.5) )\\k = 1.25](https://tex.z-dn.net/?f=k%20%3D%200.014%20%2F%20%28%20%5B0.050%5D%20%5B0.050%5D%5E%280.5%29%20%29%5C%5Ck%20%3D%201.25)
b) Overall order of reaction = a + b
Overall order of reaction = 1 + 0.5
Overall order of reaction = 1.5
Lithium Arsenate - Li3AsO4 (160g/mol). So, it’s 2,13 mol * 160 g/mol = 340,8 g.