Atoms, Elements and Compounds Worksheets | Beyond - Twinkl - Free Printable

The image shows a worksheet titled "Atoms, Elements, and Compounds." The task involves identifying and classifying substances as either elements, compounds, or mixtures. Below is the solution to the problem, along with an explanation.

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Worksheet Content Analysis

The worksheet provides definitions for:
1. Elements: Substances that consist of only one type of atom.
2. Compounds: Substances made up of two or more different types of atoms bonded together.
3. Mixtures: Substances composed of two or more elements or compounds that are not chemically combined.

Additionally, there is a table listing various substances, their formulas, and their classifications (element, compound, or mixture).

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Task Instructions

The task requires labeling each substance in the table as either:
- Element
- Compound
- Mixture

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Solution

Here is the completed classification for each substance:

#### Substance Table:
| Substance | Formula | Classification |
|-----------------|----------------|----------------|
| Oxygen | O₂ | Element |
| Water | H₂O | Compound |
| Salt (NaCl) | NaCl | Compound |
| Sugar (C₁₂H₂₂O₁₁)| C₁₂H₂₂O₁₁ | Compound |
| Air | N₂, O₂, CO₂ | Mixture |
| Iron | Fe | Element |
| Carbon Dioxide | CO₂ | Compound |
| Brass | Cu, Zn | Mixture |

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Explanation of Each Classification:

1. Oxygen (O₂):
- Formula: O₂
- Classification: Element
- Reason: Oxygen consists of only one type of atom (oxygen atoms). Even though it exists as diatomic molecules (O₂), it is still considered an element because all the atoms are the same.

2. Water (H₂O):
- Formula: H₂O
- Classification: Compound
- Reason: Water is made up of two different types of atoms—hydrogen (H) and oxygen (O)—bonded together in a fixed ratio (2 hydrogen atoms and 1 oxygen atom).

3. Salt (NaCl):
- Formula: NaCl
- Classification: Compound
- Reason: Salt is composed of sodium (Na) and chlorine (Cl) atoms bonded together in a fixed ratio (1 sodium atom and 1 chlorine atom).

4. Sugar (C₁₂H₂₂O₁₁):
- Formula: C₁₂H₂₂O₁₁
- Classification: Compound
- Reason: Sugar is made up of carbon (C), hydrogen (H), and oxygen (O) atoms bonded together in a specific ratio.

5. Air:
- Formula: N₂, O₂, CO₂
- Classification: Mixture
- Reason: Air is a combination of different gases (nitrogen, oxygen, carbon dioxide, etc.) that are not chemically bonded. They retain their individual properties.

6. Iron (Fe):
- Formula: Fe
- Classification: Element
- Reason: Iron consists of only one type of atom (iron atoms).

7. Carbon Dioxide (CO₂):
- Formula: CO₂
- Classification: Compound
- Reason: Carbon dioxide is made up of carbon (C) and oxygen (O) atoms bonded together in a fixed ratio (1 carbon atom and 2 oxygen atoms).

8. Brass:
- Formula: Cu, Zn
- Classification: Mixture
- Reason: Brass is an alloy composed of copper (Cu) and zinc (Zn). These metals are mixed physically but not chemically bonded, so brass is a mixture.

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Final Answer

The completed table is as follows:

| Substance | Formula | Classification |
|-----------------|----------------|----------------|
| Oxygen | O₂ | Element |
| Water | H₂O | Compound |
| Salt (NaCl) | NaCl | Compound |
| Sugar (C₁₂H₂₂O₁₁)| C₁₂H₂₂O₁₁ | Compound |
| Air | N₂, O₂, CO₂ | Mixture |
| Iron | Fe | Element |
| Carbon Dioxide | CO₂ | Compound |
| Brass | Cu, Zn | Mixture |

Boxed Final Answer:
\[
\boxed{
\begin{array}{|c|c|c|}
\hline
\text{Substance} & \text{Formula} & \text{Classification} \\
\hline
\text{Oxygen} & \text{O}_2 & \text{Element} \\
\text{Water} & \text{H}_2\text{O} & \text{Compound} \\
\text{Salt (NaCl)} & \text{NaCl} & \text{Compound} \\
\text{Sugar (C}_{12}\text{H}_{22}\text{O}_{11}) & \text{C}_{12}\text{H}_{22}\text{O}_{11} & \text{Compound} \\
\text{Air} & \text{N}_2, \text{O}_2, \text{CO}_2 & \text{Mixture} \\
\text{Iron} & \text{Fe} & \text{Element} \\
\text{Carbon Dioxide} & \text{CO}_2 & \text{Compound} \\
\text{Brass} & \text{Cu, Zn} & \text{Mixture} \\
\hline
\end{array}
}
\]