Question

Practice

Answer 1

Answer and Explanation:

For each reaction, it is useful to detail which are the reactants (left side of the equation) and which are the products (right side of the equation), to deduce the chemical formulas.

1. Solid lithium reacts with water to produce hydrogen gas and a solution of lithium hydroxide.

Reactants: lithium element in solid-state (Li(s)) and water (H₂O) in the liquid-state. Products: hydrogen gas which is a diatomic molecule (H₂) and lithium hydroxide, which is a base formed by lithium cation Li⁺ and OH⁻ anion (LiOH).

Li(s) + H₂O(l) → H₂(g) + LiOH(aq)

2. Solid sodium reacts with gaseous chlorine to produce sodium chloride.

Reactants: sodium metal in solid-state (Na(s)) and chlorine which is a diatomic gas (Cl₂). Products: sodium chloride, which is a salt formed by sodium and chloride together (NaCl).

Na(s) + Cl₂(g) → NaCl(s)

3. Solid calcium carbonate breaks down into carbon dioxide gas, oxygen gas, and solid calcium.

It is a decomposition reaction, so we have only one reactant: calcium carbonate, which is a salt composed of carbonate anion (CO₃⁻²) and calcium ion (Ca²⁺). Products: carbon dioxide (CO₂), oxygen gas which is diatomic (O₂), and solid calcium (Ca(s)).

CaCO₃(s) → CO₂(g) + O₂(g) + Ca(s)

4. Solid iron(II) sulfate and a solution of barium chloride react to form solid barium sulfate and a solution of  iron (II) chloride.

Reactants: iron(II) sulfate which is an ionic compound formed by the sulfate ion (SO₄²⁻) and iron ion (with two positive charges: Fe²⁺), and barium chloride which is a salt of barium ion (Ba²⁺) and two chloride ions (Cl⁻). Products: the salts formed by ion exchange, barium sulfate (BaSO₄), and iron (II) chloride (FeCl₂).

FeSO₄(s) + BaCl₂(aq) → BaSO₄(s) + FeCl₂(aq)

5. Solutions of hydrochloric acid and sodium hydroxide react to produce liquid water with sodium chloride  dissolved in it.

It is the classical neutralization reaction. Reactants: hydrochloric acid (HCl) and the strong base sodium hydroxide (NaOH). Products: water (H₂O) and the salt formed by the anion provided by the acid (Cl⁻) and the cation provided by the base (Na⁺): NaCl.

HCl(aq) + NaOH(aq) → H₂O(l) + NaCl(aq)