A lab group reacts sodium oxide (Na2O) with hydrochloric acid (HCl) to produce sodium chloride (NaCl) and water (H2O). When writing their lab report, they came up with the following equation to represent the reaction:

Question

Na2O + HCl -> NaCl + H2O

Does this equation satisfy the Law of Conservation of Matter? Why or why not?
Responses
A Yes, since there are 5 reactant atoms and 5 product atoms.Yes, since there are 5 reactant atoms and 5 product atoms.
B Yes, since there is a subscript of 2 on both sides on the equation.Yes, since there is a subscript of 2 on both sides on the equation.
C No, since there are two sodium atoms as reactants, but only one sodium atom as a product.No, since there are two sodium atoms as reactants, but only one sodium atom as a product.
D No, since there is a liquid and a solid as reactants, but a gas and a solid as a product.No, since there is a liquid and a solid as reactants, but a gas and a solid as a product.

Answer 1

The correct response is C: No, since there are two sodium atoms as reactants, but only one sodium atom as a product.

To explain:

In the given equation:

Na2O + HCl -> NaCl + H2O

• On the left (reactants), we have:
  • 2 sodium (Na) atoms from Na2O,
  • 1 oxygen (O) atom from Na2O,
  • 1 chlorine (Cl) atom from HCl,
  • 1 hydrogen (H) atom from HCl.

That totals to:

• 2 Na
• 1 O
• 1 Cl
• 1 H

Which sums to 2 + 1 + 1 + 1 = 5 atoms.

• On the right (products), we have:
  • 1 sodium (Na) atom from NaCl,
  • 1 chlorine (Cl) atom from NaCl,
  • 2 hydrogen (H) atoms from H2O,
  • 1 oxygen (O) atom from H2O.

That totals to:

• 1 Na
• 1 Cl
• 2 H
• 1 O

Which sums to 1 + 1 + 2 + 1 = 5 atoms.

However, there is an imbalance in the sodium atoms specifically. The reactants have 2 sodium atoms while the products only have 1 sodium atom. This means the equation does not satisfy the Law of Conservation of Matter, as the number of each type of atom is not the same on both sides. The equation must be balanced properly to reflect the conservation of matter.