A student poured 50 cm³ water into a beaker and measured the water's temperature - Edexcel - GCSE Chemistry - Question 4 - 2019 - Paper 1
Question 4
A student poured 50 cm³ water into a beaker and measured the water's temperature.
The student added 1.00 g calcium chloride to the water, stirred the mixture and th... show full transcript
Worked Solution & Example Answer:A student poured 50 cm³ water into a beaker and measured the water's temperature - Edexcel - GCSE Chemistry - Question 4 - 2019 - Paper 1
Step 1
Give the name of the apparatus that could be used to measure 1.00 g of calcium chloride.
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Answer
The apparatus that could be used to measure 1.00 g of calcium chloride is a weighing scale or analytical balance.
Step 2
Explain, using these results, the type of heat energy change that occurs when calcium chloride dissolves in water.
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Answer
The dissolution of calcium chloride in water results in an endothermic reaction. The temperature increase from 21 °C to 32 °C indicates that the system absorbs heat from the surroundings. The added calcium chloride takes in energy, thus raising the temperature of the solution.
Step 3
Which hazard symbol would be expected to be seen on a container of calcium chloride?
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Answer
The hazard symbol that would be expected to be seen on a container of calcium chloride is D, which represents a substance that poses health hazards.
Step 4
Give a safety precaution that the student should take during the experiment.
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Answer
A safety precaution that the student should take during the experiment is to wear gloves and goggles to protect against skin contact and eye exposure to calcium chloride.
Step 5
State one way in which the apparatus could be changed to reduce the amount of heat energy lost during the experiment.
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To reduce the amount of heat energy lost during the experiment, the apparatus could be insulated using a lid or insulating material around the beaker.
Step 6
Calculate the volume of this solution, in cm³, that contains 9.0 g of calcium chloride.
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Answer
To find the volume of the solution, use the concentration formula:
ext{Concentration (g/dm³)} = rac{ ext{mass of solute (g)}}{ ext{volume of solution (dm³)}}
