Which of the following laboratory procedures best illustrates the law of conservation of mass? (Assume the product of the reaction includes the mass of any unused reactants.) Reacting 12 g of C with 32 g of O2 to form 44 g of CO2
Weighing 100 g of Cu powder and 100 g of Fe filings
Heating 100 g of CaCO3 to produce 56 g of CaO
Dissolving 10 g of NaCl in 100 g of water

The correct answer is Reacting 12 g of C with 32 g of O2 to form 44 g of CO2

Explanation:

In chemistry, the law of conservation implies the total mass of the initial substances (reactants) is preserved during the chemical reaction, and therefore it is expected the mass is the same at the end of the reaction. This occurs only in the first statement because the initial products or reactants have a total mass of 44 grams (12 g + 32 g = 44 g), and this is the mass of the final products (44 g of CO2).  

Reacting 12 g of C with 32 g of O2 to form 44 g of CO2

Explanation:

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