Which sample equation best illustrates the Law of Conservation of Mass? A. 12 grams reactant X + 10 grams reactant Y → 2 grams product Z + 7 grams product K
B. 5 grams reactant E + 5 grams reactant F → 20 grams product G + 5 grams product H
C . 10 grams reactant Q + 9 grams reactant R → 90 grams product S + 90 grams product
D . 20 grams reactant U + 3 grams reactant V → 23 grams product W

D . 20 grams reactant U + 3 grams reactant V → 23 grams product W

Explanation:

Law of conservation of mass states:

The mass of a closed system (As a reaction), is neither created or destroyed.

That is, the mass of reactants is equal to mass of products.

A. In reaction A 22g of reactants produce 9g of products. This reaction doesn't illustrates the law of conservation of mass.

B. 10g reactant produce 25g of products. This reaction doesn't illustrates the law of conservation of mass.

C. 19g of reactants produce 180g of products. This reaction doesn't illustrates the law of conservation of mass.

D. 23g of reactants produce 23g of products. -This is the reaction that best illustrates the Law of Conservation of Mass.

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.