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CHEMISTRY, M3 EQ-Bank 17

How does the presence of a catalyst influence the rate of a chemical reaction?   (2 marks)

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→ Catalysts are substances that increase the rate of a chemical reaction without being consumed in the process.

→ They work by providing an alternative reaction pathway with a lower activation energy, which is the energy required for the reaction to occur. Because of this, more reactant particles can successfully collide with enough energy to undergo the reaction at a given temperature.

→ As a result, the reaction occurs faster when a catalyst is present.

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→ Catalysts are substances that increase the rate of a chemical reaction without being consumed in the process.

→ They work by providing an alternative reaction pathway with a lower activation energy, which is the energy required for the reaction to occur. Because of this, more reactant particles can successfully collide with enough energy to undergo the reaction at a given temperature.

→ As a result, the reaction occurs faster when a catalyst is present.

CHEMISTRY, M3 EQ-Bank 11

Brian measured the reaction rate of 0.5 g of sodium metal in 2.0 mol/L nitric acid. The volume of hydrogen gas produced per minute was recorded both without a catalyst and with copper as a catalyst.

\begin{array} {|c|c|c|}
\hline \text{Time (minutes)} & \text{Volume of hydrogen gas (mL)} & \text{Volume of hydrogen gas (mL)} \\ & \text{no catalyst} & \text{catalyst}  \\
\hline \text{0}  & 0 & 0  \\
\hline \text{1} & 16 & 7 \\
\hline \text{2} & 30 &  13\\
\hline \text{3} & 43 & 19 \\
\hline \text{4}  & 44 & 26 \\
\hline \text{5} & 44 &  32 \\
\hline \text{6} & 44 & 38 \\
\hline \text{7} & 44 &  44 \\
\hline \end{array}

  1. On the grid below, plot a line graph for the data in the table.   (3 marks)
     
  2. Write a conclusion for the experiment.   (2 marks)

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a.    
       

b.   Experiment conclusion:

→ The rate of reaction was significantly faster when copper was used as a catalyst compared to when no catalyst was present.

→ This is because the copper catalyst provided an alternative reaction pathway with a lower activation energy, allowing the reactant particles to collide more frequently and effectively.

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a.   
     

b.   Experiment conclusion:

→ The rate of reaction was significantly faster when copper was used as a catalyst compared to when no catalyst was present.

→ This is because the copper catalyst provided an alternative reaction pathway with a lower activation energy, allowing the reactant particles to collide more frequently and effectively.

CHEMISTRY, M3 EQ-Bank 2 MC

Select the correct characteristic of a catalyst from the options below:

  1. A catalyst slows down the rate of reaction
  2. A catalyst doubles during a chemical reaction
  3. A catalyst is used up in a chemical reaction
  4. A catalyst speeds up the rate of reaction
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\(D\)

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→ A catalyst speeds up the rate of a reaction by providing an alternative pathway with lower activation energy.

→ It remains chemically unchanged at the end of the reaction and is not consumed during the process.

\(\Rightarrow D\)

CHEMISTRY, M3 EQ-Bank 9

Consider the statement:

The effectiveness of a metal catalyst is not dependent upon its surface area.

Explain if this statement correct, giving reasons for your answer.   (2 marks)

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The statement is incorrect.

→ Metal catalysts are solid and reactions occur on the catalyst surface.

→ It follows that the larger the surface, the more effective the catalyst (i.e. its “effectiveness” is dependent on the surface area).

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The statement is incorrect.

→ Metal catalysts are solid and reactions occur on the catalyst surface.

→ It follows that the larger the surface, the more effective the catalyst (i.e. its “effectiveness” is dependent on the surface area).

CHEMISTRY, M3 EQ-Bank 7

Explain the role of a catalyst in altering the rate of a reaction.   (2 marks)

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→ A catalyst increases the rate of a reaction by providing an alternate reaction pathway with a lower activation energy \((\text{E}_{a})\), and does not undergo any permanent chemical change in this process.

→ This means the threshold kinetic energy \((\text{E}_{a})\) for a successful collision between particles is lowered.

→ This leads to more successful collisions and an increase in reaction rate.

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→ A catalyst increases the rate of a reaction by providing an alternate reaction pathway with a lower activation energy \((\text{E}_{a})\), and does not undergo any permanent chemical change in this process.

→ This means the threshold kinetic energy \((\text{E}_{a})\) for a successful collision between particles is lowered.

→ This leads to more successful collisions and an increase in reaction rate.

CHEMISTRY, M3 EQ-Bank 5

The following reaction is exothermic

\(\ce{N2(g) + 3H2(g) \rightarrow \ 2NH3(g)} \)

Lead \(\ce{(Pb)}\) can be used as a catalyst for this exothermic reaction. Describe what is meant by catalyst and how it influences this chemical reaction.   (3 marks)

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→ A catalyst increases the rate of a chemical reaction without undergoing any permanent chemical reaction itself.

→ The addition of \(\ce{Pb}\) in this reaction lowers the activation energy of a successful reaction.

→ More particles will exceed activation energy \(\ce{(E_{a})}\) when they collide with each other which increases the reaction rate.

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→ A catalyst increases the rate of a chemical reaction without undergoing any permanent chemical reaction itself.

→ The addition of \(\ce{Pb}\) in this reaction lowers the activation energy of a successful reaction.

→ More particles will exceed activation energy \(\ce{(E_{a})}\) when they collide with each other which increases the reaction rate.

CHEMISTRY, M3 2012 HSC 3 MC

What effect does a catalyst have on a reaction?

  1. It increases the rate.
  2. It increases the yield.
  3. It increases the heat of reaction.
  4. It increases the activation energy.
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\(A\)

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→ A catalyst is a substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change.

\(\Rightarrow A\)

CHEMISTRY, M3 2017 VCE 1 MC

A catalyst

  1. slows the rate of reaction.
  2. ensures that a reaction is exothermic.
  3. moves the chemical equilibrium of a reaction in the forward direction.
  4. provides an alternative pathway for the reaction with a lower activation energy.
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\(D\)

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→ A catalyst increases the rate of a chemical reaction by reducing the activation energy of the reaction. Thus, by collision theory, particles require less energy than normal to react to form products.

\(\Rightarrow D\)