Question

Does this equation obey the law of

conservation of mass? Why or why not?
CuCl2(aq) + Na2S(aq) → CuS(s) + NaCl(aq)

Answer 1

No, it does not obey it, but could be balanced in order to obey it.

Step-by-step explanation:

Hello,

In this case, for the given chemical reaction we can identify the amount of each atom at both reactants and products:

- Copper: there is one copper atom at reactants as well as one copper atom at the products so it is correctly balanced.

- Chlorine: there are two chlorine atoms at the reactants and only one chlorine atom at the products, so it is not correctly balanced.

- Sulfur: there is one sulfur atom at reactants as well as one sulfur atom at the products so it is correctly balanced.

- Sodium: there are two sodium atoms at the reactants and only one sodium atom at the products, so it is not correctly balanced.

For that reason, since the law of conservation of mass states matter cannot be neither created nor destroyed, the equation as given DOES NOT obey the law of conservation of mass. Nonetheless, by balancing, it could obey such law as shown below:

`CuCl_2(aq) + Na_2S(aq) \rightarrow CuS(s) +2 NaCl(aq)`

That two placed before sodium chloride (NaCl) allow the amount of both sodium and sulfur to be same at both reactants and products.

Best regards.

Answer 2

No

Step-by-step explanation:

The equation does not obey the law of conservation of mass by not accounting to the total number of Chlorine in the products.

Law of conservation of mass states that in ordinary chemical reactions, matter can neither be created nor destroyed but can be converted from one form to another.

The equation presented was

CuCl₂ + Na₂S → CuS + NaCl

1. The total number of copper in the reactant is equal to number of Cu in product

2. Numbe of Chlorine in the reactant is 2 while in the product is just 1. Not accounted for.

3. Number of sodium on the reactant is not equal to number of sodium on the product I.e 2 on the reactant and just 1 on the product.

4. Number of sulfur on the reactant is equal to number of sodium on the product.

Correct chemical equation

CuCl₂ + Na₂S → CuS + 2NaCl