Photo AI
A student used the apparatus shown in Figure 3 to investigate the reaction between marble chips and dilute hydrochloric acid - Edexcel - GCSE Chemistry - Question 2 - 2023 - Paper 2
Question 2
A student used the apparatus shown in Figure 3 to investigate the reaction between marble chips and dilute hydrochloric acid. The student recorded the volume of gas... show full transcript
Worked Solution & Example Answer:A student used the apparatus shown in Figure 3 to investigate the reaction between marble chips and dilute hydrochloric acid - Edexcel - GCSE Chemistry - Question 2 - 2023 - Paper 2
Step 1
Plot the results shown in Figure 4
Answer
-
Prepare the grid: Ensure your graph paper is oriented correctly with an x-axis labeled "time in minutes" ranging from 0 to 6, and a y-axis labeled "volume of gas in cm³" ranging from 0 to 100.
-
Plot the points: Mark the following coordinates based on the data:
- (0, 0)
- (1, 52)
- (2, 78)
- (3, 91)
- (4, 97)
- (5, 100)
- (6, 100)
-
Draw the curve of best fit: After plotting the points, draw a smooth line connecting them, starting from (0, 0). Ensure the curve smoothly reflects the trend without any sharp angles.
Step 2
13
Answer
This part of the question refers to the number of points that must be plotted correctly on the graph. A correct response requires acknowledgment that 6 or 7 points plotted will yield full marks. Care must be taken to avoid drawing straight lines, essentially focusing on the curved nature of the reaction's volume over time.
Step 3
Explain the rate of reaction
Answer
-
Understanding the rate of reaction: The rate of reaction between marble chips and dilute hydrochloric acid is influenced by factors such as surface area and concentration.
-
Comparison of surfaces: Smaller marble chips will yield a faster reaction compared to larger sizes, increasing surface area exposes more reactant particles.
-
Time consideration: As the reaction proceeds, the concentration of reactants decreases, thus slowing the rate as reactant particles are consumed.
-
Collision theory: Fewer successful collisions occur as reactants are depleted, leading to a reduced rate of gas production over time.
Step 4
Graph to show
Answer
-
Initial reaction increase: The initial reaction will show a steep incline as gas is rapidly produced, evident in the first two minutes of the graph.
-
Levelling off: After approximately 5 minutes, the gas volume levels off around 100 cm³, indicating that the reaction is nearing completion.
-
Straight line assumption: It is also reasonable to assume that if the reaction continued beyond this point, the volume would not increase due to the limiting factor of reactants.