1-RatesOfReaction

Question 1

Name 3 different techniques to monitor the rate of a chemical reaction

Answer 1

1. Using a gas syringe- this method is used to collect soluble gases
2. Using a balance- used to monitor the mass during a chemical reaction
3. Collection over water (downward displacement of water)- this method is used to collect insoluble gases

Question 2

How do you use a gas syringe?

Answer 2

Delivery tube not cut of by any lines
Graduation marks allow a measurement to be taken

Question 3

How do you use a balance?

Answer 3

Sometimes there will be cotton wool placed on the neck of a conical flask (safety feature to stop acid splashing to to stop gas escaping)
Reading on balance will reduce due to gas escaping

Question 4

How do you display collection over water

Answer 4

Delivery tube not cut of by any lines and does NOT go through the side o the trough
Graduation marks allow a measurement to be taken

Question 5

How do you measure the reaction rate?
Explain the lines in a graph

Answer 5

As the change in the quantity being measured against time
Steep lines= fast reaction rate
Shallow slope= slow reaction rate
Levelled lines= reaction stops/ends

Question 6

What is the formula to calculate the average rate?

Answer 6

Rate= /\quantity
——————
/\ t

Question 7

What are the units used?

Answer 7

Moles - mols - mol
Mass - grams - g
Volume - litres - l
Concentration - moles per litre - moll-1
Time- seconds - s - minutes - m

Question 8

If a change in mass is measured in grams and a change in time is measure in seconds, what would the unit of rate be?

Answer 8

Grams per second - g s -1

Question 9

If a change in concentration is measure in moll-1 and a change in time is measured in min, what would the unit of rate be?

Answer 9

Moll-1min-1

Question 10

If a change in volume is measured in cm3 and a change in time is measured in mins what would the unit of rate be?

Answer 10

Cm3min-1

Question 11

What are the four factors that affect rate when altered?

Answer 11

-Temperature
-Concentration
-Particle size
-Use of a catalyst

Question 12

What must happen for a chemical reaction to take place?

Answer 12

Atoms and molecules must collide

Question 13

What is a successful collision and what happens when theres alot of sucessful collisions?

Answer 13

When collisions cause a chemical change
There is a greater increase in reaction rate

Question 14

How does altering the temperature in a chemical reaction affect the rate?

Answer 14

When the temperature is increased the particles have more energy so they move more quickly, increasing the temperature increases the rate of reaction as the particles collide more often.

Question 15

How does altering the concentration in a chemical reaction affect the rate

Answer 15

If the concentration of reactants is increased there’s more particles moving together, meaning more collisions so the reaction rate is increased.

Question 16

How does altering the particle size in a chemical reaction affect the rate?

Answer 16

Decreasing particle size increases surface area meaning theres a greater space for collisions to take place, which increases the rate of reaction.

Question 17

How does using a catalyst in a chemical reaction affect the rate?

Answer 17

Catalysts provide surface for reactions to take place. Molecules are held at a suitable angle for collisions which increases the chance of successful collisions.
Catalysts alter the rate of a reaction allowing it to be done at a lower temperature.