When the reaction of magnesium burning in oxygen is balanced, what coefficient is placed before magnesium oxide?
Answer and explanation
Correct answer: Two
The unbalanced equation is \(\mathrm{Mg + O_2 \rightarrow MgO}\). There are 2 oxygen atoms on the left, so a coefficient of 2 is placed before \(\mathrm{MgO}\): \(\mathrm{Mg + O_2 \rightarrow 2MgO}\). There are then 2 magnesium atoms on the right, so placing 2 before magnesium gives the balanced equation \(\mathrm{2Mg + O_2 \rightarrow 2MgO}\). Therefore, the correct coefficient is 2; using 1 would leave the oxygen atoms unbalanced.
Frequently asked questions
What is the correct answer to this question?
Two
Why is this the correct answer?
The unbalanced equation is \(\mathrm{Mg + O_2 \rightarrow MgO}\). There are 2 oxygen atoms on the left, so a coefficient of 2 is placed before \(\mathrm{MgO}\): \(\mathrm{Mg + O_2 \rightarrow 2MgO}\). There are then 2 magnesium atoms on the right, so placing 2 before magnesium gives the balanced equation \(\mathrm{2Mg + O_2 \rightarrow 2MgO}\). Therefore, the correct coefficient is 2; using 1 would leave the oxygen atoms unbalanced.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Chemical Reactions and Equations.
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