Page from a physical science workbook illustrating the four main types of chemical reactions alongside practice problems.

Let’s go through each question one by one.

---

Question 1: Name five general types of reactions.

From the textbook section (pages 199–204) and the diagram shown in the image, the five general types are:

- Synthesis
- Decomposition
- Single Replacement
- Double Replacement
- Combustion

✔ These are standard reaction types taught in introductory chemistry.

---

Question 2: Circle the letter of each equation that represents a synthesis reaction.

A synthesis reaction is when two or more simple substances combine to form one more complex product. General form: A + B → AB

Let’s check each option:

a. 2Na + Cl₂ → 2NaCl
→ Sodium and chlorine combine to make sodium chloride. ✔ This is synthesis.

b. 2MgO → 2Mg + O₂
→ One compound breaks into two elements. ✘ This is decomposition.

c. 2H₂O → 2H₂ + O₂
→ Water breaks down into hydrogen and oxygen. ✘ Also decomposition.

d. Zn + 2HCl → ZnCl₂ + H₂
→ Zinc replaces hydrogen in HCl. ✘ This is single replacement.

So only a is correct.

✔ Answer for Q2: a

---

Question 3: Is the following sentence true or false? A decomposition reaction is the opposite of a synthesis reaction.

Synthesis: A + B → AB
Decomposition: AB → A + B

Yes — they are opposites.

✔ True

---

Question 4: Write the equation for the decomposition of calcium carbonate into calcium oxide and carbon dioxide gas.

Calcium carbonate = CaCO₃
Calcium oxide = CaO
Carbon dioxide = CO₂

So:

CaCO₃ → CaO + CO₂

We should note it’s a decomposition, so one reactant becomes multiple products. The equation is already balanced as written.

✔ Equation: CaCO₃ → CaO + CO₂

---

Question 5: Copper reacts with silver nitrate in a single-replacement reaction. What are the products?

In single replacement, a more reactive metal displaces a less reactive one from its compound.

Copper (Cu) is more reactive than silver (Ag), so it will replace Ag in AgNO₃.

Reaction: Cu + AgNO₃ → ?

Products: Copper(II) nitrate and silver metal.

Why copper(II)? Because copper commonly forms +2 ions in such reactions.

So:
Cu + 2AgNO₃ → Cu(NO₃)₂ + 2Ag

But we’re just asked for the *products*, not the full balanced equation.

Looking at options:

a. copper(I) oxide and silver oxide → ✘ No oxides involved here.

b. copper(I) nitrate and silver → Possible, but copper usually goes to +2 state unless specified.

c. copper(II) nitrate and silver → ✔ Correct. Standard product.

d. copper, nitrogen, and silver nitrate → ✘ Doesn’t make sense; no breakdown like that.

Even though copper can sometimes form +1, in this context (standard high school chem), it’s assumed to form +2.

✔ Answer: c

---

Final Answers Summary:

Q1: Synthesis, Decomposition, Single Replacement, Double Replacement, Combustion
Q2: a
Q3: True
Q4: CaCO₃ → CaO + CO₂
Q5: c

──────────────────────────────────────

Final Answer:
1. Synthesis, Decomposition, Single Replacement, Double Replacement, Combustion
2. a
3. True
4. CaCO₃ → CaO + CO₂
5. c