Multiple Choice
Consider the chemical equation: 2H_2 + O_2 ightarrow 2H_2O. How many reactants are involved in this reaction, and how many products are created?
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3. Chemical Reactions
Balancing Chemical Equations
Multiple Choice
Which set of coefficients correctly balances the chemical equation: Mg + O_2 → MgO?
A
Mg_2 + O_2 → 2 MgO
B
2 Mg + O_2 → 2 MgO
C
Mg + O_2 → MgO_2
D
Mg + 2 O_2 → MgO
Verified step by step guidance1
Write down the unbalanced chemical equation: \(\mathrm{Mg} + \mathrm{O}_2 \rightarrow \mathrm{MgO}\).
Count the number of atoms of each element on both sides of the equation. On the left, there is 1 Mg atom and 2 O atoms; on the right, there is 1 Mg atom and 1 O atom.
Balance the oxygen atoms first. Since oxygen appears as \(\mathrm{O}_2\) on the left and as a single O in \(\mathrm{MgO}\) on the right, place a coefficient of 2 in front of \(\mathrm{MgO}\) to have 2 oxygen atoms on the right: \(\mathrm{Mg} + \mathrm{O}_2 \rightarrow 2 \mathrm{MgO}\).
Now balance the magnesium atoms. There are 2 Mg atoms on the right (due to the coefficient 2), so place a coefficient of 2 in front of Mg on the left: \(2 \mathrm{Mg} + \mathrm{O}_2 \rightarrow 2 \mathrm{MgO}\).
Verify that the equation is balanced by counting atoms again: 2 Mg atoms and 2 O atoms on both sides, confirming the balanced equation.
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