Chapter 7, Problem 7STP

Summary Introduction

To determine : The minimum number of chlorine (Cl) atoms needed for the given reaction.

Introduction : The reaction between methane and chlorine gas results in the formation of HCl and CCl₄. When scientists write chemical reactions, they express each component of the reaction in a chemical equation. A chemical equation shows the reactants on the left side of the arrow and the products on the right side of the arrow.

Answer to Problem 7STP

D. 8

Explanation of Solution

In a chemical reaction, matter cannot be created or destroyed. This is law of conservation of mass. Therefore, the equations must be balanced to show balance of mass. The number of atoms of each element on the reactant side must be equal to the number of atoms of the same element on the product side. Coefficients are used to balance the number of atoms. In the case of given reaction, we can see that the coefficient of chlorine is 4. So, we multiply 4 with the subscript of chlorine; i.e., 2. This gives 8 atoms of chlorine. Hence, the minimum number of chlorine atoms needed for the reaction is 8.

  

Conclusion

1. 1- The coefficient of chlorine in the equation is 4. So there are 8 atoms of chlorine. Hence, this is not a correct option.
2. 2- The coefficient of chlorine in the equation is 4. So there are 8 atoms of chlorine. Hence, this is an incorrect option.
3. 4- The coefficient of chlorine in the equation is 4. So there are 8 atoms of chlorine. Hence, this is an incorrect option.