Year 11 Chemistry Sample Practical Assessment

Question 1.

1. A 500 g rock contains 30% CaCO₃, how many Ca atoms are there? [4 marks]
2. How many oxygen atoms are there in the CaCO₃ component of the rock? [1 mark]

Question 2.

1. A sample of NaCl powder is dissolved in water 300g of water – if the mass after it is dissolved is 305 g, what is the concentration of NaCl in the solution? [4 marks]
2. A sample of NaF powder is dissolved in water 200g of water – if the mass after it is dissolved is 210 g, what is the concentration of NaF in the solution? [4 marks]

Question 3.

If a student evaporated all of the water from CuSO₄, which, when it was originally measured out and before dissolved in water it had a molar ratio of 1:6 of CuSO₄ to H₂O. If The final mass of CuSO₄ was 25 g after evaporating, how many grams were added initially? [5 marks]

Question 4.

1. Draw the following as a scientific diagram 

2. Explain a potential source of error in the above diagram, and how you could avoid this
3. Why is a blue flame used above instead of a safety flame?

Answer.

1a) 9.02 * 10^23 Ca atoms

b) 2.71 *10^24 O atoms

2a) 0.285 M

b) 1.193 M

3) 267.9 g

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