Some Chem Questions...?

Question

1. The theoretical effect of an increase in the initial concentration of a reactant can be explained in terms of collision theory because it affects:
i. The collision geometry involved in the reaction
ii. the total number of collisions that occur
iii. the fraction of collisions that are effective
iv. the required activation energy for a reaction

(only ii. is correct, please explain [i though both ii. and iii. were])

2. Which Element is being oxidized in the following reaction?
3 I2 + 10 KNO3 + 4 HCl => 6 KIO3 + 10 NO + 2 H2O + 4 KCl

a. H in HCl
b. N in KNO3
c. K in KNO3
d. I2
e. Cl in HCl

(answer is d. but i'm not sure of how to obtain all of the oxidation numbers...)

..thx ppl... this is for my chem exam review (btw)

Answer 1

4

Answer 2

in problem 2
reactants: I in I2 oxidation number is 0; K in KNO3 is +1, NO3 is -1 and the O is -2 so the N is +5; the H in HCl is +1 and the Cl in HCl is -1
products: KIO3 the K is +1, the O is -2 so the I is +5; the N in NO is +2 and the O is -2; the H in H2) is +1 and the O is -2; the K in KCl is +1 and the Cl is -1

The Iodine is being oxized going from 0 to +5, a loss of 5 electrons. The Nitrogen in NO is being reduced going from +5 to +2, a gain of 3 electrons.

problem 1. if A + B ---> C increasing the concentration of A will increase the number of collisions between A and B. It can be argued that it will also increase the number of collisions between A and A, which will not be effective collisions.

Answer 3

1. ii. The number of collisions, because the nature of the reactants and the reaction determine the proportion of collisions that are effective.

2. d. is correct. Oxidation is the loss of electrons. Species become more + or less -. In this equation, on the left hand side, I = 0, K = +1, N = +5, O = -2, H = +1, Cl = -1. On the right hand side, K = +1, I = +5, N = +2, O = -2, H = +1, O = -2, K = +1, Cl = -1

Answer 4

INCREASE IN INITIAL CONCENTRATION OF REACTANT FASTER THE RATE OF REACTION(the reactions are faster at begining)as number of collision that occur will increase as now more reactant particle will collide with each other to become product,hence increasing the speed of reaction
2:you have not made clear,do you want that i must explain how to find oxidation state,any how i do this question for you
its (a) part is incorrect as

oxidation state of H IN HCl is +1 and in thr right hand side,oxidation state of H in H2O IS +1 TOO, so it is unchanged so thats why a is incorrect
its b part is incorrect
as oxidation state of N in KNO3 is +5 and in the right hand in NO IT IS +2 so here it is reduced not oxidised,so b is incorrect
its c part is incorrect
as oxidation state of K in KNO3 is +1 and in the right hand side in KCL its oxidation state is Same +1.so it is unchanged,neither oxidised nor reduced,hence it is incorrect
d is correct
as oxidation state of I2 in left side is 0,AND IN IN THE RIGHT HAND SIDE IT IS +5 KIO3,so here its oxidation state has increased from 0 TO +5,so oxidation,hence correct answer
e is incorrect
oxidation state of Cl is -1 in HCl and oxidation state of Cl in right hand side in KCl is same -1,it is not changed,so it is incorrect
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