P2 - 6.1 Rates of Reaction

Question 1

What is meant by the rate of reaction

Answer 1

how fast reactants are turned into products

Question 2

name a slow example of rate of reaction

Answer 2

rusting copper

Question 3

name a medium fast example of rate of reaction

Answer 3

magnesium reacting with acid

Question 4

name a fast example of rate of reaction

Answer 4

fireworks exploding

Question 5

what 2 things can we look at to determine the rate of reaction

Answer 5

• how fast reactants are used up
• how fast products are formed

Question 6

if the rate of reaction is fast are products formed slower or faster

Answer 6

faster

Question 7

if the rate of reaction is slow are products formed slower or faster

Answer 7

slower

Question 8

what is the rate of reaction equation that includes products

Answer 8

rate of reaction = quantity of products formed/ time taken

Question 9

what is the rate of reaction equation that includes reactants

Answer 9

rate of reaction = quantity of reactants used/ time taken

Question 10

what is the quantity of products/reactants measured in

Answer 10

grams
cm^3
moles
dm^3

Question 11

what is time measured in

Answer 11

seconds
minutes

Question 12

what is the rate of reaction measured in

Answer 12

grams/s
moles/s
cm^3/s
dm^3/s

Question 13

What is the rate of reaction if 180cm^3 of hydrogen gas reacts with hydrochloric acid in 2 minutes

Mg + 2HCl -> MgCl2 + H2

Answer 13

Hydrogen gas is a product so we use the equation:
rate of reaction = quantity of products formed/ time taken

convert 2 mins into seconds = 120s
180/120= 1.5cm^3/s

Question 14

What is the rate of reaction of 3g of magnesium reacting with acid for 4 minutes

Mg + 2HCl -> MgCl2 + H2

Answer 14

magnesium is a reactant so we use the equation:
rate of reaction = quantity of reactant used/time taken

convert 4 mins to seconds = 60x4 = 240s
3/240 = 0.0125g/s

Question 15

At what time is the rate of reaction is a reaction reacting fastest

Answer 15

at the very beginning

Question 16

At what time is the rate of reaction is a reaction reacting slowest

Answer 16

at the end

Question 17

why does the rate of reaction get slower over time

Answer 17

the reactants are being used up so there is a less concentration of atoms to react

Question 18

what goes along the x axis on a rate of reaction graph

Answer 18

time

Question 19

what goes along the y axis of a rate of reaction graph

Answer 19

• mass of reactants
  or
• volume of product formed

Question 20

in a rate of reaction graph with a y axis of mass of reactant describe what it would look like

Answer 20

-start from the quantity of reactant
- first it will rapidly fall
- ease/slow overtime until it is all used up (at 0g)

Question 21

in a rate of reaction graph with a y axis of volume of product produced describe what it would look like

Answer 21

• starts at 0 (bottom of graph)
• quickly increase due to lots of hydrogen produced and high concentration of both reactants
• becomes less steep as reaction slows, lower concentration reacting
• becomes a flat line on graph showing reaction has stopped/completed

Question 22

in a rate of reaction graph with y axis off volume of product why does it quickly increase

Answer 22

lots oof hydrogen produced in a high concentration of both reactants

Question 23

What is the rate of reaction if 0.6moles of magnesium reacts with hydrochloric acid in 2 minutes
(answer must be in minutes)

Answer 23

magnesium is a reactant
rate of reaction = quantity of reactant used/ time taken

rate of reaction is being measured in mol/min
0.6/2 = 0.3mol/min

Question 24

which is a larger unit? cm^3 or dm^3

Answer 24

1 cm^3 = 1000 dm^3
cm^3

Question 25

how do you convert from dm^3 into cm^3

Answer 25

x1000

Question 26

how do you convert from cm^3 into dm^3

Answer 26

/1000

Question 27

what is 5000cm^3 in dm^3

Answer 27

cm^3 -> dm^3 = /1000
5000/1000 = 5dm^3

Question 28

what is 50dm^3 in cm^3

Answer 28

dm^3 -> cm^3 = x1000
50x1000= 50000cm^3

Question 29

When you strike a match it causes a tiny amount of red phosphorus to be converted to white phosphorus, which can then ignite spontaneously in air. Is this reaction slow or fast

Answer 29

fast

Question 30

0.4g of magnesium reacts completely with dilute hydrochloric acid in 1 min 20s. What is the overall rate of reaction? give your answer in g/s

Answer 30

magnesium is a reactant
rate of reaction = quantity of reactant used/ time taken

1min 20s = 60+20=80s
0.4/80 = 0.005g/s

Question 31

Mg + 2HCl -> MgCl2 + H2
90cm^3 of hydrogen gas was produced after 5 mins. What is the overall rate of reaction? give your answer in cm^3/s

Answer 31

hydrogen gas is a product
rate of reaction = quantity of product formed/time taken
5 mins = 60x5= 300s
90/300 = 0.3cm^3/s