chemical change: rate & extent

Question 1

what is the effect on equilibrium in increasing concentration (reactant)?

Answer 1

-equil shifts to right to reduce effect of increasing con
when con of a reactant increases, equil moves to oppose change and create more product from excess reactant

Question 2

what is the effect on equilibrium in decreasing concentration (reactant)?

Answer 2

-equil shifts to reactant side to increase concentration again

Question 3

what is the effect on equilibrium in increasing temp (reactant)?

Answer 3

-equil moves in endo direction to reverse change

Question 4

what is the effect on equilibrium in decreasing temp (reactant)?

Answer 4

-equil moves in exo direction to reverse change

Question 5

what is the effect on equilibrium in increased pressure (reactant)?

Answer 5

-equil shifts in direction that produces smaller no. of molecules of gas to decrease pressure again

Question 6

what is the effect on equilibrium in decreased pressure (reactant)?

Answer 6

-equil shifts in direction that produces larger no. of molecules of gas to increase pressure again

Question 7

what’s normally used as catalysts?

Answer 7

-transition metals are used widely as catalysts: they have variable oxidation states allowing them to readily donate and accept different numbers of electrons

Question 8

how do catalysts work?

Answer 8

catalysts work by attracting reactant molecules on to the surface (of catalyst) and so providing an alternate reaction pathway of lower energy

Question 9

different chemicals store…

Answer 9

different amount of energy in bonds

Question 10

what is a neutralisation reaction?
what does it produce?

Answer 10

-acid + base
-salt + water

Question 11

in a reaction profile of an endothermic reaction, would reactants or products be higher

Answer 11

-products
-as it has more energy absorbed from surroundings

Question 12

in a reaction profile of exothermic reaction, would reactants or products be higher

Answer 12

-reactants
-as it loses energy over time to surroundings, so products will have less energy

Question 13

what is activation energy

Answer 13

-minimum amount of energy (that reactant particles) need(ed) in order to collide w/ e/o & react

Question 14

what is an exo react.

Answer 14

-a reaction that releases thermal energy to surroundings

Question 15

On reaction profile diagrams, the activation energy is always the….

Answer 15

increase in energy from reactants to peak of curve

Question 16

pros and cons of hydrogen-oxygen fuel cells

Answer 16

pros
-only require H and O, both abundant
-don’t prod any pollutants as waste
-(fuel cells) simple devices, lasts longer than batteries, less polluting to dispose of

cons
-H is a gas, takes up more storage space than fossil fuels or batteries
-explosive when mixed w/ air
-process to make it comes from en. from fossil fuels, counter-prod.

Question 17

complete the reversible reaction:

hydrated copper sulfate (blue) <—–> anhydrous….. + …

Answer 17

-copper sulfate
+ water

Question 18

equilibrium lies to the left if there are more ……. and when it lies on right there are more ……..

Answer 18

-reactants
-products

Question 19

state la chatelier’s principle

Answer 19

change the conditions of a reversible reaction
position of equilibrium will shift to try and counteract change

Question 20

(in sealed system)
when you inc temp in an equilibrium reaction, the position moves in the ……. direction to ………….
when you decr. temp, the position moves in the …. direction to ……..

Answer 20

-endo direction to decr. temp again
-exo direction to inc temp by releasing more energy

Question 21

if pressure inc in and equilibrium system, the position will shift to the side ……….
if pressure decr in and equilibrium system, the position will shift to the side ……….

Answer 21

-with the least molecules to inc decr pressure
-with most molecules to incr pressure

Question 22

finish the reaction:
magnesium + hydrochloric acid ->

Answer 22

magnesium chloride + hydrogen

Question 23

What is collision theory:

Answer 23

-chem reactions can only happen if reactant particles collide with sufficient energy
-rate determined by frequency of collisions