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In a reaction, 12.0 g of magnesium completely reacts with 8.0 g of oxygen to form magnesium oxide. According to the Law of Conservation of Mass, what is the total mass of the product formed?
16.0 g
20.0 g
4.0 g
24.0 g
20.0 g
According to the Law of Conservation of Mass, matter can neither be created nor destroyed in a chemical reaction. Therefore, the total mass of the products must be exactly equal to the total mass of the reactants involved.
According to the Law of Conservation of Mass, matter can neither be created nor destroyed in a chemical reaction. Therefore, the total mass of the products must be exactly equal to the total mass of the reactants involved.
Think of building a lego castle; if you use 12 bricks for the base and 8 bricks for the towers, the completed castle will always consist of exactly 20 bricks, regardless of how you assemble them.
Mass┬аof┬аReactants=Mass┬аof┬аProducts
12.0┬аg┬а(Mg)+8.0┬аg┬а(O2тАЛ)=20.0┬аg┬а(MgO)
In the chemical reaction 2Mg+O2тАЛтЖТ2MgO, the reactants (magnesium and oxygen) combine to form a single product (magnesium oxide). Because no atoms are lost or gained, the sum of the initial masses of the reactants must equal the final mass of the product produced.
The Law of Conservation of Mass was proposed by Antoine Lavoisier in 1789.
The total mass of substances present before a chemical reaction equals the total mass after the reaction.
Chemical equations must be balanced to reflect this conservation of atoms and mass.
Allows for precise stoichiometric calculations in chemical synthesis.
Does not account for mass-energy equivalence (E=mc2) in nuclear reactions where mass loss is significant.
Balancing chemical equations.
Industrial quality control in reactant usage.
The reaction follows the stoichiometry where 24.3 g of Mg reacts with 16 g of O, but in this specific problem context, the ratio is predefined.
Other options are incorrect as they imply mass is either created (24 g) or destroyed (4 g or 16 g), violating the fundamental conservation law.
B is correct тАФ The total mass of the products is equal to the sum of the masses of the reactants, which is 12.0┬аg+8.0┬аg=20.0┬аg.
Always check if your balanced chemical equation accounts for every atom present on both sides; if the mass doesn't balance, the equation is likely incorrect.