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A pupil used the apparatus shown in the diagram to quantitatively investigate the effect of temperature on the solubility of copper sulfate crystals in water - Junior Cycle Science - Question 5 - 2010
Question 5
A pupil used the apparatus shown in the diagram to quantitatively investigate the effect of temperature on the solubility of copper sulfate crystals in water. 100 g ... show full transcript
Worked Solution & Example Answer:A pupil used the apparatus shown in the diagram to quantitatively investigate the effect of temperature on the solubility of copper sulfate crystals in water - Junior Cycle Science - Question 5 - 2010
Step 1
Draw a graph of copper sulfate crystals dissolved (solubility) against temperature
Answer
To plot the graph, follow these steps:
- Mark the x-axis for temperature (°C) and y-axis for solubility (g/100 g).
- Identify the points from the data table and plot them: (0, 14), (20, 21), (40, 29), (60, 40), (80, 55), (100, 75).
- Ensure that the points are plotted accurately, with a smooth curve connecting all points.
Step 2
Use your graph to estimate the solubility of copper sulfate crystals at 10 °C
Answer
From the plotted graph, draw a horizontal line from 10 °C on the x-axis to meet the curve. From the point of intersection, draw a vertical line down to the x-axis to read off the solubility value. It can be estimated that the solubility at 10 °C is around 16-17 g/100 g.
Step 3
Describe, using an appropriate labelled diagram in the box provided, how to grow and collect crystals of copper sulfate from the solution produced at 100 °C
Answer
- Heat the solution to 100 °C on a water bath until fully dissolved.
- Leave the solution to cool slowly to room temperature, allowing crystals to form gradually.
- Once crystals begin to form, filter the solution to collect the crystals.
- Rinse the collected crystals with distilled water to remove impurities.
- Allow the crystals to dry on a filter paper and store them in a dry container.
Diagram: Include a diagram showing heat source, evaporation, and crystal formation.
Step 4
What is the pH scale? How can pH be measured?
Answer
The pH scale is a measurement of acidity and alkalinity, ranging from 0 to 14. A pH of 7 is neutral, below 7 indicates acidity, and above 7 indicates alkalinity.
How to measure pH:
- Using pH paper: Dip pH paper into the solution and compare the color change against a pH scale.
- Using a pH meter: Immerse the pH probe in the solution and read the digital display for an accurate pH value.
Step 5