4. (a) 3.14 g of solid copper sulfate was dissolved in water and made up to 250 cm³ of solution - Edexcel - GCSE Chemistry Combined Science - Question 4 - 2022 - Paper 1
Question 4
4. (a) 3.14 g of solid copper sulfate was dissolved in water and made up to 250 cm³ of solution.
Calculate the concentration of this copper sulfate solution in g dm... show full transcript
Worked Solution & Example Answer:4. (a) 3.14 g of solid copper sulfate was dissolved in water and made up to 250 cm³ of solution - Edexcel - GCSE Chemistry Combined Science - Question 4 - 2022 - Paper 1
Step 1
Calculate the concentration of this copper sulfate solution in g dm⁻³.
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Answer
To calculate the concentration of copper sulfate in g dm⁻³, use the formula:
extconcentration(gdm−3ext)=volume (dm3)mass (g)
Here, the mass of copper sulfate is 3.14 g, and the volume of the solution is 250 cm³, which can be converted to dm³:
250cm3=0.250dm3
Substituting the values into the formula gives:
concentration=0.250dm33.14g=12.56g dm−3
Step 2
State what would be seen in the reaction.
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Answer
In the reaction between sodium hydroxide and copper sulfate, a blue precipitate of copper hydroxide will be formed.
Step 3
Complete the balanced equation for the reaction by adding a number in front of NaOH.
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Answer
The balanced equation is:
2NaOH+CuSO4→Cu(OH)2+Na2SO4
Step 4
Describe how to obtain a pure, dry sample of the precipitate of copper hydroxide from the reaction mixture.
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Answer
To obtain a pure, dry sample of copper hydroxide precipitate:
First, filter the reaction mixture to separate the precipitate from the liquid. Use filter paper in a funnel for this step.
Rinse the precipitate with distilled water to remove any soluble impurities.
Place the filtered residue in a warm place or use a warm environment to allow it to dry completely.
Optionally, you may use gentle heat to speed up the drying process, but do not boil or heat too vigorously to avoid decomposition.
