Introducing chemical reactions

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Question 3
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Two students heat some zinc carbonate, ZnCO3\text{ZnCO}_3ZnCO3​.

Look at the equation for the reaction.

ZnCO3(s)⟶ZnO(s)+CO2(g)\text{ZnCO}_3\text{(s)} \longrightarrow \text{ZnO(s)} + \text{CO}_2\text{(g)}ZnCO3​(s)⟶ZnO(s)+CO2​(g) Zinc carbonate⟶Zinc oxide+Carbon dioxide\text{Zinc carbonate} \longrightarrow \text{Zinc oxide} + \text{Carbon dioxide}Zinc carbonate⟶Zinc oxide+Carbon dioxide

a.

What is the meaning of (s) in the equation?

[1]
b.

Look at their results.

Mass of zinc carbonate (g)Mass of zinc oxide (g)Mass of carbon dioxide (g)
2.511.630.88
5.023.261.76
7.534.892.64
10.046.52...................................

Complete the table.

[1]
c.

Student A states:

"If I heat 25.1 g of zinc carbonate, I will make 8.8 g of zinc oxide and 16.3 g of carbon dioxide."

Is student A correct? Explain your answer.

[2]
d.

Student B investigates another reaction.

Look at the equations.

2Mg(s)+O2(g)⟶2MgO(s)2\text{Mg(s)} + \text{O}_2\text{(g)} \longrightarrow 2\text{MgO(s)}2Mg(s)+O2​(g)⟶2MgO(s) magnesium+oxygen⟶magnesium oxide\text{magnesium} + \text{oxygen} \longrightarrow \text{magnesium oxide}magnesium+oxygen⟶magnesium oxide

Calculate the relative formula mass of magnesium oxide, MgO\text{MgO}MgO. (Relative atomic masses: Mg=24.3\text{Mg} = 24.3Mg=24.3, O=16.0\text{O} = 16.0O=16.0)

[1]
e.

Use the relative formula mass of magnesium oxide and the relative atomic masses of magnesium and oxygen to show if mass is conserved during this reaction.

[3]

Introducing chemical reactions Questions

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