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Question 1

What is the speed of a reaction called?

Answer 1

Its rate

Question 2

How can graphs help in understanding reaction rates?

Answer 2

They show how the rate (speed) of a reaction changes

Question 3

What does a steeper line on a reaction rate graph indicate?

Answer 3

A faster rate of reaction

Question 4

What happens to the slope of the graph over time as reactants are used up?

Answer 4

The line becomes less steep

Question 5

What is the effect of changing conditions on reaction rates?

Answer 5

Reaction rates can change when conditions like time change

Question 6

What does a faster reaction look like on a graph compared to a slower reaction?

Answer 6

It has a steeper line at the beginning and goes flat more quickly

Question 7

What does line 4 on a reaction graph indicate?

Answer 7

More product is formed due to more reactants at the start

Question 8

What is collision theory?

Answer 8

An idea that explains reaction rates based on particle collisions

Question 9

What is the minimum amount of energy needed for a reaction to occur called?

Answer 9

Activation energy

Question 10

What relationship does collision frequency have with reaction rates?

Answer 10

The more often particles collide, the faster the reaction will happen

Question 11

Fill in the blank: For particles to react, they have to collide with each other with enough _______.

Answer 11

Energy

Question 12

What factors can affect the rate of reaction?

Answer 12

• Temperature
• Concentration
• Pressure of a gas
• Surface area

Question 13

What happens to reaction rates when temperature increases?

Answer 13

Particles move faster and collide more often

Question 14

What is the effect of increasing concentration on reaction rates?

Answer 14

More particles in the same volume lead to more collisions

Question 15

What effect does surface area have on reaction rates?

Answer 15

Larger surface area increases reaction rates

Question 16

What are the four factors that affect the rate of a chemical reaction?

Answer 16

• Temperature
• Concentration of a solution (or pressure of a gas)
• Surface area of a solid
• Whether a catalyst is used

These factors influence how frequently particles collide and the energy involved in the reactions.

Question 17

How does temperature affect the rate of reaction?

Answer 17

Increasing temperature causes particles to move faster, leading to more frequent collisions with sufficient energy to react.

Higher temperatures increase the kinetic energy of particles, which increases the rate of reaction.

Question 18

What is collision frequency?

Answer 18

How often the particles collide.

Collision frequency is an important concept as it affects the rate of reaction.

Question 19

Fill in the blank: A _______ is a substance that speeds up a reaction without being used up in the reaction.

Answer 19

[catalyst]

Question 20

What effect does increasing the surface area of a solid reactant have on the rate of reaction?

Answer 20

It increases the rate of reaction by making more of the solid’s particles available for collisions.

Smaller pieces of solid have a larger surface area to volume ratio, leading to more frequent collisions with other reactants.

Question 21

True or False: Catalysts are part of the reaction equation.

Answer 21

False

Catalysts are not consumed in the reaction and do not appear in the reaction equation.

Question 22

What is the role of enzymes in biological reactions?

Answer 22

Enzymes are biological catalysts that catalyse reactions in living things.

Enzymes lower the activation energy needed for reactions, similar to chemical catalysts.

Question 23

What happens to the activation energy when a catalyst is used?

Answer 23

The activation energy is lowered.

This allows reactions to occur more easily and quickly.

Question 24

What is the effect of high concentration on reaction rates?

Answer 24

Higher concentration increases the rate of reaction due to more frequent collisions between reactant particles.

Increased concentration means more particles are present in a given volume.

Question 25

Fill in the blank: Breaking a solid reactant into smaller pieces increases its _______.

Answer 25

[surface area]

Question 26

In an experiment with magnesium ribbon and powdered magnesium, which would react faster?

Answer 26

Powdered magnesium ## Footnote The greater surface area of powdered magnesium allows for more frequent collisions with hydrochloric acid.

Question 27

What is a reaction profile?

Answer 27

A graphical representation showing the energy changes during a reaction, including activation energy. ## Footnote Reaction profiles illustrate the difference in activation energy with and without a catalyst.

Question 28

What happens to reaction rates if the particles collide with enough energy?

Answer 28

The reaction will occur. ## Footnote Sufficient energy is required for a successful reaction to take place.

Question 29

What is the first step in measuring rates of reaction?

Answer 29

Measure out a set volume of dilute hydrochloric acid using a measuring cylinder.

Question 30

What should be done after measuring the hydrochloric acid?

Answer 30

Carefully pour it into a conical flask.

Question 31

What is the importance of attaching the delivery tube and gas syringe quickly?

Answer 31

To prevent any gas from escaping.

Question 32

When should the stopwatch be started in the experiment?

Answer 32

Immediately after adding the marble chips to the flask.

Question 33

What should be done at regular intervals during the reaction?

Answer 33

Take readings of the volume of gas produced and record them in a table.

Question 34

How accurate are gas syringes in measuring gas volume?

Answer 34

Gas syringes give volume to the nearest milliliter, making them quite accurate.

Question 35

What must be kept constant when repeating the experiment with different concentrations of acid?

Answer 35

The mass of marble chips, temperature, and all other variables.

Question 36

What does a higher volume of gas produced in a set time indicate?

Answer 36

A faster rate of reaction.

Question 37

What materials are involved in the reaction that produces a yellow precipitate?

Answer 37

Sodium thiosulfate and hydrochloric acid.

Question 38

What visual cue indicates the reaction between sodium thiosulfate and hydrochloric acid?

Answer 38

The black cross disappearing through the solution.

Question 39

How can the mass balance be used to measure the amount of gas produced?

Answer 39

As gas forms and escapes, the mass of the reaction mixture decreases.

Question 40

What does a quicker drop in mass on the balance indicate?

Answer 40

A faster rate of reaction.

Question 41

What is a drawback of using a mass balance for this experiment?

Answer 41

It releases gas into the room, which is not safe if the gas is toxic.

Question 42

What is the relationship between concentration of acid and time taken for a reaction?

Answer 42

Higher concentration of acid results in less time for the reaction to occur.

Question 43

Fill in the blank: A gas syringe measures the _______ of gas produced in a reaction.

Answer 43

volume

Question 44

True or False: The faster the mark disappears in the sodium thiosulfate and hydrochloric acid reaction, the faster the reaction.

Answer 44

True

Question 45

What should be done if the gas produced in the reaction is toxic?

Answer 45

Ensure proper ventilation or use a closed system to contain the gas.

Question 46

What gas is released in the reaction being investigated?

Answer 46

Sulfur dioxide ## Footnote This reaction requires a well-ventilated area due to the release of sulfur dioxide.

Question 47

What equipment is mentioned for measuring gas in the experiment?

Answer 47

Gas syringe ## Footnote The gas syringe is used to measure the volume of gas produced in the reaction.

Question 48

What safety equipment is recommended for the experiment?

Answer 48

Safety goggles and lab coat ## Footnote These items are essential for ensuring safety while conducting the experiment.

Question 49

What is the relationship between concentration of HCl and time taken for the mark to disappear?

Answer 49

Higher concentration leads to faster reaction ## Footnote As the concentration of HCl increases, the time taken for the mark to disappear decreases.

Question 50

Fill in the blank: The concentration of HCl in the experiment is measured in _______.

Answer 50

g/dm3

Question 51

What should be kept constant in the experiment when changing HCl concentration?

Answer 51

Two factors ## Footnote Factors such as temperature and surface area of the reactants should be controlled.

Question 52

True or False: The experiment can be conducted without any safety precautions.

Answer 52

False ## Footnote Safety precautions are necessary due to the nature of the chemicals involved.

Question 53

How does the concentration of HCl affect the speed of the reaction?

Answer 53

The higher the concentration, the faster the reaction ## Footnote This is evidenced by the decrease in time taken for the mark to disappear with increasing concentration.

Question 54

What was the time taken for the mark to disappear at a concentration of 36 g/dm3?

Answer 54

184 seconds

Question 55

List the concentrations of HCl used in the experiment.

Answer 55

* 18 g/dm3 * 36 g/dm3 * 54 g/dm3 * 72 g/dm3

Question 56

What is the effect of using different concentrations of acid in the experiment?

Answer 56

It affects the rate of reaction ## Footnote The change in concentration alters how quickly the reaction occurs.

Question 57

What does the type of graph you can draw depend on?

Answer 57

The experiment you did.

Question 58

What should be placed on the x-axis when drawing a graph of gas volume over time?

Answer 58

Time.

Question 59

What should be placed on the y-axis when drawing a graph of gas volume over time?

Answer 59

Volume of gas.

Question 60

How do you indicate the amount of gas produced at each time interval on a graph?

Answer 60

Draw a small cross at each point.

Question 61

What is the purpose of drawing a line of best fit on a graph?

Answer 61

To represent the overall trend of the data.

Question 62

Fill in the blank: A tangent helps you compare ______ rates at different points.

Answer 62

reaction.

Question 63

What is the first step to determine the reaction rate at a specific time on a graph?

Answer 63

Position a ruler at the desired time point.

Question 64

True or False: The steeper the tangent line on a graph, the faster the reaction rate.

Answer 64

True.

Question 65

What is the formula for calculating the mean rate of reaction?

Answer 65

Mean Rate = amount of product / time.

Question 66

In the mean rate formula, what does 'amount of product' refer to?

Answer 66

The total mass or volume of product formed.

Question 67

What does a flat line on a reaction graph indicate?

Answer 67

The reaction has finished.

Question 68

How can you calculate the mean rate for a reaction from a graph?

Answer 68

Determine the total product formed and divide by the time taken.

Question 69

What should you do to find the amount of product produced between two specific time points on a graph?

Answer 69

Work out the difference in amount produced.

Question 70

What is the significance of the term 'line of best fit'?

Answer 70

It represents the best approximation of the data points in a graph.

Question 71

What is the formula for calculating the mean rate of a reaction?

Answer 71

Mean rate = amount of reactant used (or product formed) ÷ time ## Footnote This formula is essential for determining reaction rates.

Question 72

If a reaction takes 120 seconds and produces 3.0 g of product, what is the mean rate of reaction?

Answer 72

0.025 g/s ## Footnote Calculation: 3.0 g ÷ 120 s = 0.025 g/s

Question 73

How can the rate of a gas reaction be measured?

Answer 73

In cm³ rather than in grams ## Footnote This is important when measuring gaseous products.

Question 74

What does a flat line on a graph of gas volume indicate?

Answer 74

The reaction has finished ## Footnote This shows that no more product is being formed.

Question 75

How do you find the mean rate of reaction between two time points on a graph?

Answer 75

1) Calculate the amount of product formed between the points. 2) Calculate the time difference. 3) Divide the amount of product by the time taken. ## Footnote This method allows for precise calculation of rates over specific intervals.

Question 76

If 15 cm³ of gas is produced at 20 s and 19 cm³ at 40 s, what is the mean rate of reaction between these times?

Answer 76

0.20 cm³/s ## Footnote Calculation: (19 cm³ - 15 cm³) ÷ (40 s - 20 s) = 4.0 cm³ ÷ 20 s = 0.20 cm³/s

Question 77

True or False: The mean rate of reaction can be calculated using only numerical data.

Answer 77

True ## Footnote Both numerical data and graphical data can be used to determine the mean rate.

Question 78

What is the mean rate of a reaction that takes 200 seconds and uses 6.0 g of reactant?

Answer 78

0.030 g/s ## Footnote Calculation: 6.0 g ÷ 200 s = 0.030 g/s

Question 79

Fill in the blank: The mean rate of reaction is calculated by dividing the amount of reactant used (or product formed) by _______.

Answer 79

time ## Footnote This is a fundamental concept in reaction kinetics.

Question 80

What are reversible reactions?

Answer 80

Reactions that can be reversed.

Question 81

What symbol indicates a reversible reaction?

Answer 81

-

Question 82

What happens to the concentrations of reactants in a reversible reaction as they react?

Answer 82

Their concentrations fall.

Question 83

What is equilibrium in the context of reversible reactions?

Answer 83

The amounts of products and reactants aren't changing anymore.

Question 84

What is required for equilibrium to be reached in a reversible reaction?

Answer 84

The reaction must take place in a 'closed system'.

Question 85

What does it mean if there are more products than reactants at equilibrium?

Answer 85

The reaction is going in the forwards direction.

Question 86

What can shift the direction of a reversible reaction?

Answer 86

Changing the conditions (temperature, pressure, or concentration).

Question 87

What happens to ammonium chloride when heated?

Answer 87

It breaks down to form ammonia and hydrogen chloride.

Question 88

What type of reaction occurs when heat is taken in?

Answer 88

Endothermic.

Question 89

What type of reaction occurs when heat is released?

Answer 89

Exothermic.

Question 90

Fill in the blank: If a reaction is endothermic in one direction, it will be ______ in the other.

Answer 90

exothermic.

Question 91

What does 'anhydrous' mean?

Answer 91

Without water.

Question 92

What does 'hydrated' mean?

Answer 92

With water.

Question 93

What is a closed system?

Answer 93

A system where none of the reactants or products can escape.

Question 94

True or False: Equilibrium means there are equal amounts of products and reactants.

Answer 94

False.

Question 95

What does it indicate if the reaction is at equilibrium?

Answer 95

The rates of the forward and backward reactions are equal.

Question 96

What is the relationship between endothermic and exothermic reactions in reversible processes?

Answer 96

The amount of energy taken in by the endothermic reaction is the same as the amount given out during the exothermic reaction.