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Copper chloride solution reacts with potassium hydroxide solution to form a precipitate of copper hydroxide and potassium chloride in solution - Edexcel - GCSE Chemistry - Question 4 - 2018 - Paper 1
Question 4
Copper chloride solution reacts with potassium hydroxide solution to form a precipitate of copper hydroxide and potassium chloride in solution. (a) Balance the equa... show full transcript
Worked Solution & Example Answer:Copper chloride solution reacts with potassium hydroxide solution to form a precipitate of copper hydroxide and potassium chloride in solution - Edexcel - GCSE Chemistry - Question 4 - 2018 - Paper 1
Step 1
Balance the equation for the reaction by putting numbers in the spaces provided.
Answer
The balanced equation for the reaction is:
This shows that two moles of potassium hydroxide react with one mole of copper(II) chloride to produce one mole of copper(II) hydroxide and two moles of potassium chloride.
Step 2
Which of the following is the relative formula mass of copper hydroxide, Cu(OH)₂?
Answer
To calculate the relative formula mass of copper hydroxide, Cu(OH)₂:
- Atomic mass of Cu = 63.5
- Atomic mass of O = 16
- Atomic mass of H = 1
Thus, the relative formula mass is:
The correct answer is C 97.5.
Step 3
Calculate the percentage by mass of potassium in potassium chloride.
Answer
To find the percentage by mass of potassium in potassium chloride (KCl):
- Relative atomic mass of K = 39
- Relative atomic mass of Cl = 35.5
- Relative formula mass of KCl = 39 + 35.5 = 74.5
Now, the percentage by mass of potassium is calculated as follows:
ext{Percentage by mass of K} = rac{ ext{Mass of K}}{ ext{Mass of KCl}} imes 100 = rac{39}{74.5} imes 100 \\ ext{Percentage by mass of K} \\ = 52.23\% \\ ext{(approximately)}