Step-by-Step Guidance for General Chemistry: Chemical Formulae and Reactions

Q1. Write the formula of a metal that can react with acid to form salt and hydrogen gas. Write the reaction equation.

Background

Topic: Metal-Acid Reactions

This question tests your understanding of how metals react with acids to produce a salt and hydrogen gas, a classic single displacement reaction.

Key Terms and Formulas:

• Metal (M): Typically a reactive metal such as zinc, magnesium, or iron.

• Acid (HA): Common acids include hydrochloric acid (HCl), sulfuric acid (H2SO4).

• General reaction: $\text{M} + \text{HA} \rightarrow \text{MA} + \text{H}_2$

Step-by-Step Guidance

1. Choose a suitable metal that reacts with acids (e.g., zinc, magnesium).

2. Write the formula for the metal and the acid (e.g., Zn and HCl).

3. Set up the reaction equation: $\text{Zn} + 2\text{HCl} \rightarrow \text{ZnCl}_2 + \text{H}_2$

4. Balance the equation to ensure atoms and charges are conserved.

Try solving on your own before revealing the answer!

Final Answer: Zn + 2HCl → ZnCl2 + H2

This is a typical reaction for a metal (zinc) with hydrochloric acid, producing zinc chloride and hydrogen gas.

Q2. Write the formula for a salt formed when a metal reacts with a non-metal.

Background

Topic: Ionic Compound Formation

This question tests your understanding of how metals and non-metals combine to form ionic compounds (salts).

Key Terms and Formulas:

• Metal (M): Donates electrons to become a cation.

• Non-metal (X): Accepts electrons to become an anion.

• General formula: $\text{M} + \text{X} \rightarrow \text{MX}$

Step-by-Step Guidance

1. Identify a metal (e.g., sodium) and a non-metal (e.g., chlorine).

2. Write their formulas: Na and Cl.

3. Combine to form the salt: $\text{Na} + \text{Cl} \rightarrow \text{NaCl}$

4. Check the charges to ensure the compound is neutral.

Try solving on your own before revealing the answer!

Final Answer: NaCl

Sodium chloride is formed when sodium reacts with chlorine.

Q3. Write a balanced equation for the reaction of iron(III) chloride with sodium hydroxide.

Background

Topic: Double Displacement Reactions

This question tests your ability to write and balance equations for reactions between ionic compounds, often resulting in a precipitate.

Key Terms and Formulas:

• Iron(III) chloride: FeCl3

• Sodium hydroxide: NaOH

• General reaction: $\text{FeCl}_3 + 3\text{NaOH} \rightarrow \text{Fe(OH)}_3 + 3\text{NaCl}$

Step-by-Step Guidance

1. Write the formulas for reactants: FeCl3 and NaOH.

2. Predict the products: Fe(OH)3 (precipitate) and NaCl.

3. Set up the equation: $\text{FeCl}_3 + 3\text{NaOH} \rightarrow \text{Fe(OH)}_3 + 3\text{NaCl}$

4. Balance the equation for atoms and charges.

Try solving on your own before revealing the answer!

Final Answer: FeCl3 + 3NaOH → Fe(OH)3 + 3NaCl

Iron(III) hydroxide forms as a precipitate in this reaction.

Q4. Write a balanced equation for the reaction of silver nitrate with sodium chloride.

Background

Topic: Precipitation Reactions

This question tests your ability to write equations for reactions that produce an insoluble salt (precipitate).

Key Terms and Formulas:

• Silver nitrate: AgNO3

• Sodium chloride: NaCl

• General reaction: $\text{AgNO}_3 + \text{NaCl} \rightarrow \text{AgCl} + \text{NaNO}_3$

Step-by-Step Guidance

1. Write the formulas for reactants: AgNO3 and NaCl.

2. Predict the products: AgCl (precipitate) and NaNO3.

3. Set up the equation: $\text{AgNO}_3 + \text{NaCl} \rightarrow \text{AgCl} + \text{NaNO}_3$

4. Balance the equation for atoms and charges.

Try solving on your own before revealing the answer!

Final Answer: AgNO3 + NaCl → AgCl + NaNO3

Silver chloride forms as a white precipitate in this reaction.

Q5. Write a balanced equation for the reaction of barium chloride with sodium sulfate.

Background

Topic: Precipitation Reactions

This question tests your ability to write equations for reactions that produce an insoluble salt (precipitate).

Key Terms and Formulas:

• Barium chloride: BaCl2

• Sodium sulfate: Na2SO4

• General reaction: $\text{BaCl}_2 + \text{Na}_2\text{SO}_4 \rightarrow \text{BaSO}_4 + 2\text{NaCl}$

Step-by-Step Guidance

1. Write the formulas for reactants: BaCl2 and Na2SO4.

2. Predict the products: BaSO4 (precipitate) and NaCl.

3. Set up the equation: $\text{BaCl}_2 + \text{Na}_2\text{SO}_4 \rightarrow \text{BaSO}_4 + 2\text{NaCl}$

4. Balance the equation for atoms and charges.

Try solving on your own before revealing the answer!

Final Answer: BaCl2 + Na2SO4 → BaSO4 + 2NaCl

Barium sulfate forms as a white precipitate in this reaction.

Q6. Write a balanced equation for the reaction of calcium carbonate with hydrochloric acid.

Background

Topic: Acid-Carbonate Reactions

This question tests your understanding of how carbonates react with acids to produce a salt, water, and carbon dioxide.

Key Terms and Formulas:

• Calcium carbonate: CaCO3

• Hydrochloric acid: HCl

• General reaction: $\text{CaCO}_3 + 2\text{HCl} \rightarrow \text{CaCl}_2 + \text{H}_2\text{O} + \text{CO}_2$

Step-by-Step Guidance

1. Write the formulas for reactants: CaCO3 and HCl.

2. Predict the products: CaCl2, H2O, and CO2.

3. Set up the equation: $\text{CaCO}_3 + 2\text{HCl} \rightarrow \text{CaCl}_2 + \text{H}_2\text{O} + \text{CO}_2$

4. Balance the equation for atoms and charges.

Try solving on your own before revealing the answer!

Final Answer: CaCO3 + 2HCl → CaCl2 + H2O + CO2

This reaction produces calcium chloride, water, and carbon dioxide gas.