Calcium nitrate solution reacts with sodium carbonate solution - Edexcel - GCSE Chemistry - Question 4 - 2013 - Paper 1

The colour produced in a flame test by calcium ions is:

C orange-red

To carry out a flame test on a solid, follow these steps:

1. CLEAN the flame test wire using hydrochloric acid to avoid contamination.
2. SAMPLE by putting a small amount of the solid onto the wire.
3. TEST by holding the wire in a Bunsen flame and observing the resulting colour.

The percentage yield of carbon dioxide can be calculated using the formula:

$\text{Percentage Yield} = \left( \frac{\text{actual yield}}{\text{theoretical yield}} \right) \times 100$

Here, the actual yield is 40 g and the theoretical yield is 44 g:

$\text{Percentage Yield} = \left( \frac{40}{44} \right) \times 100 \approx 90.9\%$

A possible reason for the formation of only 40 g of carbon dioxide could be that:

• The reaction is incomplete, meaning that not all the calcium carbonate was converted into carbon dioxide.
• Some gas may have escaped during the heating process, leading to less carbon dioxide being collected.

Ionic compounds:

D have high melting points