5.1 For this investigation, write down the function of the: 5.1.1 Graduated syringe 5.1.2 Copper(II) oxide 5.2 How will you know when the reaction is completed? 5.3 Write down the independent variable for this investigation. 5.4 Use the collision theory to fully explain the difference in reaction rates of experiment I and experiment II. 5.5 The graphs below show changes in the potential energy during the decomposition of hydrogen peroxide in experiment I and experiment II. 5.5.1 Is energy ABSORBED or RELEASED during this reaction? Give a reason for the answer. 5.5.2 Which ONE of the curves, A or B, represents experiment II? 5.6 Calculate the rate, in mol·dm⁻³·min⁻¹, at which 50 cm³ of hydrogen peroxide decomposes in experiment II. Assume that 1 mole of gas occupies a volume of 25 dm³ at 30 °C.

NSC Physical Sciences Rate and Extent of Reactions: 5.1 For this investigation, writ

5.1 For this investigation, write down the function of the: 5.1.1 Graduated syringe 5.1.2 Copper(II) oxide 5.2 How will you know when the reaction is completed? 5.3 Write down the independent variable for this investigation - NSC Physical Sciences - Question 5 - 2017 - Paper 2

Question 5

5.1 For this investigation, write down the function of the: 5.1.1 Graduated syringe 5.1.2 Copper(II) oxide 5.2 How will you know when the reaction is completed? ... show full transcript

Worked Solution & Example Answer:5.1 For this investigation, write down the function of the: 5.1.1 Graduated syringe 5.1.2 Copper(II) oxide 5.2 How will you know when the reaction is completed? 5.3 Write down the independent variable for this investigation - NSC Physical Sciences - Question 5 - 2017 - Paper 2

Step 1

5.1.1 Graduated syringe

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Answer

The graduated syringe is used to measure the volume of oxygen gas produced during the decomposition of hydrogen peroxide. It allows for accurate quantification of the gas, which is essential for analyzing the reaction's progress.

Step 2

5.1.2 Copper(II) oxide

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Answer

Copper(II) oxide acts as a catalyst in this reaction. Its presence speeds up the decomposition of hydrogen peroxide by lowering the activation energy required for the reaction to proceed.

Step 3

5.2 How will you know when the reaction is completed?

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The reaction is completed when no further gas is produced, indicated by the cessation of oxygen being collected in the graduated syringe. The plunger of the syringe will stop moving, confirming that all the hydrogen peroxide has decomposed.

Step 4

5.3 Write down the independent variable for this investigation.

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Answer

The independent variable for this investigation is the presence of copper(II) oxide, as it is manipulated to observe its effect on the rate of reaction.

Step 5

5.4 Use the collision theory to fully explain the difference in reaction rates of experiment I and experiment II.

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Answer

According to collision theory, a reaction rate is influenced by the frequency and energy of collisions between reactant particles. In experiment I, hydrogen peroxide decomposes without a catalyst, resulting in fewer effective collisions and a slower reaction rate. In contrast, experiment II utilizes copper(II) oxide which lowers the activation energy, enabling more particles to collide with sufficient energy. Therefore, more effective collisions occur in experiment II, leading to a significantly faster reaction rate.

Step 6

5.5.1 Is energy ABSORBED or RELEASED during this reaction? Give a reason for the answer.

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Energy is RELEASED during this reaction. The decomposition of hydrogen peroxide into water and oxygen results in products with lower potential energy compared to the reactants, indicating that the reaction is exothermic.

Step 7

5.5.2 Which ONE of the curves, A or B, represents experiment II?

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Curve B represents experiment II, as it depicts the potential energy changes associated with a reaction that involves a catalyst, which lowers the activation energy.

Step 8

5.6 Calculate the rate, in mol·dm⁻³·min⁻¹, at which 50 cm³ of hydrogen peroxide decomposes in experiment II.

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To calculate the rate, use the formula: $n(O_2) = \frac{V}{V_m}$ where $V = 0.4 ext{ dm}^3$ and $V_m = 25 ext{ dm}^3$ . This gives: $n(O_2) = \frac{0.4}{25} = 0.016 \text{ mol}$ . The reaction takes 5.8 minutes, so: $\text{Rate} = \frac{n}{t} = \frac{0.016}{5.8} \approx 0.00276 \text{ mol·min}^{-1} \approx 0.11 \text{ mol·dm}^{-3}· ext{min}^{-1}$ .

5.1 For this investigation, write down the function of the: 5.1.1 Graduated syringe 5.1.2 Copper(II) oxide 5.2 How will you know when the reaction is completed? 5.3 Write down the independent variable for this investigation - NSC Physical Sciences - Question 5 - 2017 - Paper 2

5.1.1 Graduated syringe

5.1.2 Copper(II) oxide

5.2 How will you know when the reaction is completed?

5.3 Write down the independent variable for this investigation.

5.4 Use the collision theory to fully explain the difference in reaction rates of experiment I and experiment II.

5.5.1 Is energy ABSORBED or RELEASED during this reaction? Give a reason for the answer.

5.5.2 Which ONE of the curves, A or B, represents experiment II?

5.6 Calculate the rate, in mol·dm⁻³·min⁻¹, at which 50 cm³ of hydrogen peroxide decomposes in experiment II.

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