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The diagram shows the reaction of a metal with dilute hydrochloric acid - OCR Gateway - GCSE Chemistry: Combined Science - Question 16 - 2020 - Paper 1
Question 16
The diagram shows the reaction of a metal with dilute hydrochloric acid. A student thinks she can use this reaction to place four different metals in their order of... show full transcript
Worked Solution & Example Answer:The diagram shows the reaction of a metal with dilute hydrochloric acid - OCR Gateway - GCSE Chemistry: Combined Science - Question 16 - 2020 - Paper 1
Step 1
Describe a method for valid results
Answer
To determine the reactivity of the four different metals, the student should conduct a series of experiments where each metal is reacted separately with dilute hydrochloric acid.
- Set Up the Experiment: Gather four different metals (e.g., magnesium, zinc, iron, and copper) and label them appropriately.
- Measure the Acid Volume: Use a consistent amount of dilute hydrochloric acid for each experiment, for example, 100 ml.
- Conduct the Reactions: Place a piece of each metal in a separate test tube containing the acid and observe any reaction. The student should take note of the time taken for any observable reaction to occur, such as gas evolution or temperature change.
- Control Conditions: Ensure that all tests are conducted under the same conditions (same temperature, same concentration of acid, same surface area of metals, etc.) to avoid skewed results.
Step 2
Explain how to use the results for reactivity order
Answer
After conducting the reactions, the student can analyze the results based on the rate and vigor of the reactions. The following steps outline how to establish the order of reactivity:
- Observation Analysis: Observe the amount of gas produced and the speed of the reaction for each metal.
- Faster Reactions = Higher Reactivity: Metals that produce gas more quickly or cause a vigorous reaction with the acid are more reactive than those that react slowly or not at all.
- Ranking the Metals: Once the observations are recorded, the student can rank the metals from most reactive to least reactive based on the rate of reaction observed.
- Final Order: Metals that produced a large amount of gas in a shorter time would be placed higher in the order of reactivity, while metals that did not react significantly would be placed lower. This empirical data helps to logically categorize the metals' reactivities.