rates of reaction, factors effecting the rate of reaction and catalysts

Question 1

Why are rates of reaction important in chemistry

Answer 1

the faster you make chemicals the faster you make money

Question 2

what is meant by the rate of a chemical reaction

Answer 2

how fast the reactants are changed into products

Question 3

how do you find the speed of a reaction

Answer 3

amount of reactant used or amount of product formed/ time

Question 4

how are the rates of reaction explained

Answer 4

collision theory

Question 5

what does the rate of a chemical reaction depend on

Answer 5

the frequency of collisions and the energy transfered in a collison. The higher these are the faster the reaction is

Question 6

what is activation energy

Answer 6

the minimum amout of energy paricles need to react

Question 7

what 4 things does the rate of reaction depened on

Answer 7

Temperature, the concentartion of a solution or the pressure of a gas, surface area and the prescence of a catalyst

Question 8

what does more collisions mean

Answer 8

the higher the rate of reaction

Question 9

why does increasing the temperature mean increased rate

Answer 9

if you increase the temperature the particles move faster so they will have more collisions. Increasing the tempersture of the particles also gives them more energy so more successful collisions will happen.

Question 10

what does happens if you increase the pressure of a gas

Answer 10

the particles are more crowded wich means the frequency of collisions between particles increases

Question 11

what does a steeper line mean on a graph when describing rates of reaction and what does it mean when the line becomes less steep

Answer 11

a faster rate of reaction
the reactants are being used up

Question 12

why does cutting a solid into pieces increase the rate of reaction

Answer 12

it increases the objects surface area to volume ratio which means more of the solid will be exposed

Question 13

what do catalysts do

Answer 13

increase the reaction rate and reduce energy costs with out being chemically changed or used up in the reaction

Question 14

how do catalysts work and how do they do this

Answer 14

they decrease the activation energy needed by providing an alternate reacting pathway

Question 15

how do you do the precipitation reaction to measure rates of reaction

Answer 15

1) you mix 2 colourless solutions which produces a precipitate, which clouds the solution
2) mix the 2 reactant solutions and put the flask on a piece of paper that has a mark on it
3) measure how long it takes for the mark to disapear , the longer it takes the slower the reacting, the faster it takes the quicker the reaction

Question 16

how do you measure how surface area affects rate

Answer 16

put marble chip and dilute HCL in a conical flask with a gas syergine atatched to the top- measure the volume of CO2 given off

Question 17

how do you investigate how concentration of acid affects rate

Answer 17

marble chips praticle but more concentrated HCL

Question 18

how do you do the praticle to show how reaction rate is affected by temperature

Answer 18

1) sodium thiosulfate and hyrdochloric acid are both clear solutions, they react together to form a yellow precipitate of sulfur
2) You can measure the rate by timing how long it takes for a black mark to disapear
3) use differnet temps of water to see difference

Question 19

how do you measure how using catalysts affects rate

Answer 19

set up apparaus the same way as the marble chips experiment but add a catalyst (mn02) and hydrogen peroxide
measure how much gas is given off with the same time but differnet catalysts