50+ elements and compounds worksheets for 10th Class on Quizizz ... - Free Printable

Problem Analysis:

The provided image contains a quiz on "Elements and Compounds" with 10 questions. Below, I will solve each question step by step and explain the reasoning.

---

Question 1: Which of the following represents an element?

- Options:
- A) H₂O
- B) CaCO₃
- C) NaCl
- D) H₂

#### Solution:
- H₂O (Water): This is a compound made up of two elements: hydrogen (H) and oxygen (O).
- CaCO₃ (Calcium Carbonate): This is a compound made up of three elements: calcium (Ca), carbon (C), and oxygen (O).
- NaCl (Sodium Chloride): This is a compound made up of two elements: sodium (Na) and chlorine (Cl).
- H₂ (Hydrogen Gas): This is an element because it consists of only one type of atom (hydrogen).

#### Answer:
D) H₂

---

Question 2: Which of the following is not a compound?

- Options:
- A) CO₂
- B) NaCl
- C) Cl
- D) HCl

#### Solution:
- CO₂ (Carbon Dioxide): This is a compound made up of two elements: carbon (C) and oxygen (O).
- NaCl (Sodium Chloride): This is a compound made up of two elements: sodium (Na) and chlorine (Cl).
- Cl (Chlorine): This is an element because it consists of only one type of atom (chlorine).
- HCl (Hydrogen Chloride): This is a compound made up of two elements: hydrogen (H) and chlorine (Cl).

#### Answer:
C) Cl

---

Question 3: Salt has a chemical formula of NaCl. Salt is a...

- Options:
- A) Compound
- B) Element
- C) Mixture
- D) None of the Above

#### Solution:
- NaCl (Sodium Chloride): Salt is composed of two different elements (sodium and chlorine) that are chemically bonded together. Therefore, it is a compound.

#### Answer:
A) Compound

---

Question 4: What cannot be broken down into other substances?

- Options:
- A) Compound
- B) Solids
- C) Element
- D) Mixture

#### Solution:
- Compound: A compound can be broken down into its constituent elements through chemical reactions.
- Solids: Solids are a physical state of matter and can be further broken down into compounds or elements.
- Element: An element is made up of only one type of atom and cannot be broken down into simpler substances by chemical means.
- Mixture: A mixture is a combination of two or more substances that are not chemically combined and can be separated physically.

#### Answer:
C) Element

---

Question 5: What is made up of two or more elements that are chemically combined?

- Options:
- A) Mixture
- B) Element
- C) Solids
- D) Compound

#### Solution:
- Mixture: A mixture is a combination of two or more substances that are not chemically combined.
- Element: An element is made up of only one type of atom.
- Solids: Solids are a physical state of matter and do not define the chemical composition.
- Compound: A compound is made up of two or more different elements that are chemically combined in fixed proportions.

#### Answer:
D) Compound

---

Question 6: How many elements are represented in the compound Na₂CO₃?

- Options:
- A) 2
- B) 1
- C) 3
- D) 4

#### Solution:
- Na₂CO₃ (Sodium Carbonate): This compound is composed of three different elements:
- Sodium (Na)
- Carbon (C)
- Oxygen (O)

#### Answer:
C) 3

---

Final Answers:

1. D) H₂
2. C) Cl
3. A) Compound
4. C) Element
5. D) Compound
6. C) 3

Boxed Final Answer:
\[
\boxed{D, C, A, C, D, C}
\]