Sodium oxide reacts with water to produce sodium hydroxide. Suppose 12.7 g of sodium oxide is combined with 39.8 g of water. When the reaction is complete, all the sodium oxide has been consumed. According to the law of conservation of mass, which is a true statement?
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According to the law of conservation of mass, mass is neither created nor destroyed during a chemical reaction. This means that the total mass of the reactants should be equal to the total mass of the products.
To determine which statement is true, we need to calculate the masses of the reactants and products.
The given mass of sodium oxide is 12.7 g, and the mass of water is 39.8 g.
First, we need to determine the molar mass of each substance:
- Sodium oxide (Na2O): Na (sodium) has a molar mass of 22.99 g/mol, and O (oxygen) has a molar mass of 16.00 g/mol. Therefore, the molar mass of Na2O is 22.99 g/mol + 16.00 g/mol + 16.00 g/mol = 54.99 g/mol.
- Water (H2O): H (hydrogen) has a molar mass of 1.01 g/mol, and O (oxygen) has a molar mass of 16.00 g/mol. Therefore, the molar mass of H2O is 1.01 g/mol + 1.01 g/mol + 16.00 g/mol = 18.02 g/mol.
Next, we can calculate the number of moles for each substance:
- Moles of sodium oxide = mass / molar mass = 12.7 g / 54.99 g/mol ≈ 0.231 mol
- Moles of water = mass / molar mass = 39.8 g / 18.02 g/mol ≈ 2.211 mol
The balanced chemical equation for the reaction is: Na2O + H2O → 2 NaOH
From the equation, we can see that 1 mole of Na2O reacts to produce 2 moles of NaOH.
Therefore, the number of moles of NaOH produced would be 2 * 0.231 mol = 0.462 mol.
Finally, we can calculate the mass of NaOH produced:
- Mass of NaOH = moles of NaOH * molar mass of NaOH = 0.462 mol * (22.99 g/mol + 16.00 g/mol + 1.01 g/mol) ≈ 27.56 g.
Now, let's compare the total mass of the reactants to the total mass of the products:
- Total mass of reactants = mass of sodium oxide + mass of water = 12.7 g + 39.8 g ≈ 52.5 g
- Total mass of products = mass of NaOH = 27.56 g
Since the total mass of the reactants (52.5 g) is not equal to the total mass of the products (27.56 g), we can conclude that the law of conservation of mass is not satisfied in this reaction.