Year 10 Science · Unit 2 · Lesson 14
Foundation Worksheet
Learning Goals
Match each term to its definition
Draw a line connecting each term on the left to its correct definition on the right. Or write the matching letter next to each term.
| Term | Your answer | Definition |
|---|---|---|
| Initial rate | A. A variable that is kept the same in all trials to ensure the test is fair. | |
| Anomaly | B. The slope of a graph at a particular point, steeper slope = faster rate. | |
| Controlled variable | C. The reaction rate at the very start of the experiment, found from the steepest part of the curve. | |
| Independent variable | D. A data point that does not fit the expected pattern, may indicate an error or genuine anomaly. | |
| Gradient | E. The difference between the experimental measurement and the true or expected value due to limitations of equipment or method. | |
| Error | F. The variable that the experimenter deliberately changes to test its effect. |
Read the reaction rate graph
The graph below shows CO₂ volume produced over time for three HCl concentrations (low, medium, high) reacting with marble chips. One data point is an anomaly. Answer the questions below.
Data: Simulated CaCO₃ + HCl investigation. All trials used the same mass of marble chips.
(a) Which concentration has the fastest initial rate? How can you tell from the graph?
(b) All three lines reach approximately the same final volume of CO₂. Explain why this is expected.
(c) The circled point on the medium concentration line at t = 30s appears unusually low. What is an anomaly? Suggest ONE possible source of error that could cause this data point.
(d) What should the student do with this anomalous data point when drawing a line of best fit? Explain your answer.
1. Name TWO sources of error that are common in gas collection experiments with CaCO₃ and HCl, and for each one explain how it would affect the results.
Wrap Up
In one sentence, what was the main idea of this lesson?