Kinetics, Equilibria and Redox Reactions

Question 1

what does the term reaction rate mean?

Answer 1

the change in concentration (or amount) of a reactant or product over time

Question 2

define activation energy

Answer 2

the minimum amount of kinetic energy needed for the particles to successfully collide and react

Question 3

what does the area under a Maxwell Boltzmann curve represent?

Answer 3

the total number of molecules

Question 4

what does the peak of a Maxwell Boltzmann curve represent?

Answer 4

the most likely energy of any single molecule

Question 5

what effect does temperature have on reaction rate?

Answer 5

an increase of temperature increases the rate of reaction

more kinetic energy greater
chance of a successful collision

Question 6

what effect does temperature have on a Maxwell Boltzmann curve?

Answer 6

increasing temp moves curve to the right as more particles have a higher amount of energy

lowering temp shifts curve to the left

Question 7

what effect does concentration have on reaction rate?

Answer 7

increasing concentration means particles are closer together so will collide more frequently

Question 8

what effect does pressure have on reaction rate?

Answer 8

increasing pressure pushes particles closer together so the frequency of collisions is higher

Question 9

what is a catalyst?

Answer 9

a substance that increases the rate of reaction by providing an alternative rout with a lower activation energy

Question 10

what effect does concentration have on a Maxwell Boltzmann curve?

Answer 10

increasing concentration moves the curve up whilst decreasing it moves the curve down

Question 11

describe 3 ways to measure the rate of a reaction

Answer 11

draw a cross under a beaker and see how long it takes for the precipitate to form and the cross to disappear

measure the gas given off by measuring mass on balance

measure gas given off using a gas syringe

Question 12

what is a reversible reaction?

Answer 12

a reaction that goes both ways

Question 13

what does dynamic equilibrium mean?

Answer 13

it is a closed system nothing can get in or out

Question 14

state Le Chatelier’s principle

Answer 14

if a reaction at equilibrium is subject to change in concentration, pressure or temperature, the position of equilibrium will move to oppose the change

Question 15

if an equilibrium moves to the right do you get more products or reactants?

Answer 15

products

Question 16

a reaction at equilibrium is endothermic in the forwards direction. what happens to the position of equilibrium as the temp increases?

Answer 16

equilibrium will shift to the left

Question 17

what effect does a catalyst have on the position of equilibrium?

Answer 17

no effect they can not increase yield

Question 18

what effect does concentration have on the position of equilibrium?

Answer 18

increasing the concentration of the reactant will cause equilibrium to shift to the right to oppose the increase and make more product

decreasing does the opposite

Question 19

what effect does pressure have on the position of equilibrium?

Answer 19

increasing pressure shifts equilibrium to the side with least moles

decreasing does the opposite

Question 20

if a reaction is exothermic in the forwards direction what effect does increasing the temperature have on the value of kc?

Answer 20

increasing temp will shift equilibrium to the left
so the amount of product will decrease
kc will also decrease

Question 21

what is a reducing agent?

Answer 21

an agent that donates electrons and gets oxidised

Question 22

what is a oxidising agent?

Answer 22

agent that accepts electrons and gets reduced

Question 23

what is the oxidation state of hydrogen in H2 gas?

Answer 23

zero

Question 24

what is the oxidation state of a compound with no overall charge?

Answer 24

zero

Question 25

what is the oxidation state of identical atoms bonded together?

Answer 25

zero

Question 26

what is the oxidation state of an ion?

Answer 26

its charge

Question 27

what is the oxidation state of a compound ion?

Answer 27

its charge times by how many atoms if there is multiple
SO4  2-     
overall ox = -2
0xygen = -2      (4x-2=-8)
s=  -2 - (-8) = +6
-8+6 = -2

Question 28

what is the usual oxidisation rate of oxygen when its in a compound?

Answer 28

-2

Question 29

where do the electrons go in the reduction part of a redox half equation?

Answer 29

on the left side of the arrow

Question 30

where do the electrons go in the oxidation part of a redox half equation?

Answer 30

on the right side of the arrow