# For the balanced chemical equation below, indicate how many atoms of each element are present on...

## Question:

For the balanced chemical equation below, indicate how many atoms of each element are present on the reactant and product sides of the chemical reaction.

{eq}\displaystyle \rm Au_2S_3 + 3H_2 \to 3H_2S+ 2Au {/eq}

## Balancing Chemical Equation:

According to the law of conservation of mass, matter cannot be created nor destroyed. This means that when writing a chemical equation, the number of atoms of all the elements on both of sides of the equation should be equal. If it is not, the introduction of a number called coefficient before the chemical formula of a substance is done in order to achieve a balanced chemical equation.

A chemical formula represents a chemical substance in a chemical equation. The subscripts of the formula denote the number of atoms of the element to which it is written after. When no such subscript is present, a value of 1 is known to be present. Furthermore, in a chemical equation, the coefficients before a chemical formula imply that it should be multiplied to the subscripts of the elements present in the formula.

Below is the balanced chemical reaction between gold (III) sulfide, {eq}\rm Au_2S_3 {/eq}, and hydrogen gas, {eq}\rm H_2 {/eq}:

{eq}\displaystyle \rm Au_2S_3 + 3H_2 \to 3H_2S+ 2Au {/eq}

A coefficient of 3 is written before hydrogen gas. Moreover, dihydrogen sulfide, {eq}\rm H_2S {/eq}, and gold, {eq}\rm Au {/eq}, have coefficients of 3, and 2, respectively. Hence, we can rewrite the equation as:

{eq}\displaystyle \rm Au_2S_3 + H_6 \to H_6S_3+ Au_2 {/eq}

By looking at the subscripts, we can say that on both sides of the balanced chemical equation, there are 2 atoms of gold, 3 atoms of sulfur, {eq}\rm S {/eq}, and 6 atoms of hydrogen, {eq}\rm H {/eq}.

What is a Chemical Equation? - Definition & Examples

from

Chapter 13 / Lesson 9
46K

In this lesson, you will learn how chemical equations are used to represent chemical reactions. You will learn that there are many pieces of information provided in a chemical equation, and you will gain an understanding of how to interpret chemical equations.