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


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.

Answer and Explanation: 1

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}.

Learn more about this topic:

What is a Chemical Equation? - Definition & Examples


Chapter 13 / Lesson 9

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.

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