Problem 82 - Chemistry: The Central Science

Question

Write a balanced equation for the reaction that occurs in each of the following cases: (a) Chlorine reacts with water. (b) Barium metal is heated in an atmosphere of hydrogen gas. (c) Lithium reacts with sulfur. (d) Fluorine reacts with magnesium metal.

Step-by-Step Solution

Answer

(a) \(Cl_2 + H_2O \to HCl + HOCl\) (b) \(Ba + H_2 \to BaH_2\) (c) \(2Li + S \to Li_2S\) (d) \(F_2 + Mg \to MgF_2\)

Step 1: (a) Chlorine reacts with water

When chlorine gas reacts with water, it forms hydrochloric acid (HCl) and hypochlorous acid (HOCl) as products. The unbalanced equation for this reaction is: Cl2 + H2O -> HCl + HOCl To balance this equation, we need to make sure there are the same number of each type of atom on both sides. In this case, balancing the number of hydrogen and chlorine atoms requires placing coefficients: \(Cl_2 + H_2O -> HCl + HOCl\) The equation is now balanced.

Step 2: (b) Barium metal is heated in an atmosphere of hydrogen gas

When barium metal (Ba) reacts with hydrogen gas (H2), it forms barium hydride (BaH2) as the product. The unbalanced equation for this reaction is: Ba + H2 -> BaH2 Since there is only one equation to balance, we need to balance the number of H atoms: \(Ba + H_2 \to BaH_2\) This equation is already balanced.

Step 3: (c) Lithium reacts with sulfur

When lithium (Li) reacts with sulfur (S), it forms lithium sulfide (Li2S) as the product. The unbalanced equation for this reaction is: Li + S -> Li2S To balance this equation, we should balance the number of lithium and sulfur atoms by placing coefficients: \(2Li + S \to Li_2S\) The equation is now balanced.

Step 4: (d) Fluorine reacts with magnesium metal

When fluorine (F2) reacts with magnesium metal (Mg), it forms magnesium fluoride (MgF2) as the product. The unbalanced equation for this reaction is: F2 + Mg -> MgF2 To balance this equation, we should balance the number of fluorine and magnesium atoms by placing coefficients: \(F_2 + Mg \to MgF_2\) This equation is already balanced.