Use the unbalanced chemical equation to answer the question
2NaHCO3 -- Na2CO + CO2
Which of the following can be added to the products to balance the equation?
1. H2o
2. H2
3. CH2OH
4. O2
The correct answer is 4. O2.
To balance the unbalanced chemical equation 2NaHCO3 -> Na2CO + CO2, you need to add the appropriate coefficients to the reactants and products.
Looking at the equation, we can see that the number of atoms of each element on both sides is not equal. There are 2 sodium (Na) atoms on the left side and only 1 sodium atom on the right side. Similarly, there are 2 hydrogen (H) atoms on the left side and 0 hydrogen atoms on the right side.
To balance the equation, we need to add coefficients in front of the formulas of the compounds.
Taking a look at the answer choices:
1. H2O: This contains oxygen (O), but we don't need to balance the oxygen atoms since they are already balanced.
2. H2: This contains hydrogen (H), but we don't need to balance the hydrogen atoms since they are already balanced.
3. CH2OH: This contains carbon (C), but we don't need to balance the carbon atoms since they are already balanced.
4. O2: This contains oxygen (O), which can be used to balance the oxygen atoms on the right side.
Therefore, the correct choice is 4. O2. Adding coefficients to the equation gives us the balanced equation:
2NaHCO3 -> Na2CO3 + CO2 + O2
To balance a chemical equation, you need to ensure that the number of atoms of each element on both sides of the equation are equal. In the given unbalanced equation:
2NaHCO3 → Na2CO + CO2
The equation is unbalanced because the number of atoms for each element on both sides is unequal.
Let's analyze each option to see which one can be added to balance the equation:
1. H2O: This option adds water (H2O) to the products. However, none of the reactants or products contain hydrogen and oxygen in imbalanced amounts, so adding water will not help balance the equation. Therefore, this option is not the correct choice.
2. H2: This option adds hydrogen gas (H2) to the products. Again, none of the reactants or products contain hydrogen, so adding hydrogen gas will not help balance the equation. Therefore, this option is not the correct choice.
3. CH2OH: This option adds a compound called CH2OH to the products. However, this compound does not contain the elements sodium, carbon, or oxygen, which are present in the reactants. Therefore, this option is not the correct choice.
4. O2: This option adds oxygen gas (O2) to the products. In the unbalanced equation, there is one oxygen atom on the left side (in NaHCO3) and three oxygen atoms on the right side (in Na2CO and CO2). By adding an O2 molecule to the left side, the number of oxygen atoms on both sides will be equalized:
2NaHCO3 + O2 → Na2CO + CO2 + H2O
This balanced equation satisfies the rule that the number of atoms for each element is equal on both sides.
Therefore, the correct answer is option 4: O2.