Identify chemical and physical changes in this educational worksheet.
Worksheet titled "Chemical and Physical Changes" with a list of ten scenarios to identify as chemical or physical changes, including examples like heating water into steam and iron rusting, with a molecular diagram in the top right corner.
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Step-by-step solution for: Chemical and Physical Changes of Matter
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Show Answer Key & Explanations
Step-by-step solution for: Chemical and Physical Changes of Matter
To solve the problem, we need to identify whether each process listed is a chemical change or a physical change. Here's a breakdown of each item:
- Chemical Change: A chemical reaction occurs, and new products are formed. The identity of the matter changes.
- Physical Change: Matter changes form but its identity does not change.
1. Heating water into steam
- Explanation: When water is heated, it changes from a liquid to a gas (steam). No new substances are formed; it's just a change in state.
- Type: Physical Change
2. Milk going sour
- Explanation: Milk going sour involves bacteria breaking down lactose into lactic acid, forming new substances.
- Type: Chemical Change
3. Dissolving sugar in water
- Explanation: Sugar dissolves in water, forming a solution. No new substances are created; it's just a mixing of molecules.
- Type: Physical Change
4. Iron rusting
- Explanation: Rusting is the oxidation of iron, where iron reacts with oxygen and water to form iron oxide (rust). New substances are formed.
- Type: Chemical Change
5. Hydrochloric acid and sodium hydroxide reacting and forming salt and water
- Explanation: Hydrochloric acid (HCl) reacts with sodium hydroxide (NaOH) to form sodium chloride (salt) and water. This is a neutralization reaction, forming new substances.
- Type: Chemical Change
6. Digesting food into nutrients
- Explanation: Digestion involves breaking down complex molecules in food into simpler molecules (e.g., proteins into amino acids). New substances are formed.
- Type: Chemical Change
7. Melting ice into water
- Explanation: Ice melting into water is a change in state from solid to liquid. No new substances are formed.
- Type: Physical Change
8. Acid rain dripping onto limestone and making carbon dioxide gas
- Explanation: Acid rain (containing sulfuric or nitric acid) reacts with calcium carbonate in limestone to form calcium sulfate/nitrate and carbon dioxide gas. New substances are formed.
- Type: Chemical Change
9. Breaking a glass into pieces
- Explanation: Breaking glass into pieces is a physical change in shape, but the glass itself remains the same material.
- Type: Physical Change
10. Hydrogen peroxide decomposing into oxygen gas and water
- Explanation: Hydrogen peroxide (H₂O₂) decomposes into water (H₂O) and oxygen gas (O₂). This is a chemical reaction forming new substances.
- Type: Chemical Change
\[
\begin{array}{|c|l|c|}
\hline
\text{No.} & \text{Process} & \text{Type} \\
\hline
1 & \text{Heating water into steam} & \text{Physical Change} \\
\hline
2 & \text{Milk going sour} & \text{Chemical Change} \\
\hline
3 & \text{Dissolving sugar in water} & \text{Physical Change} \\
\hline
4 & \text{Iron rusting} & \text{Chemical Change} \\
\hline
5 & \text{Hydrochloric acid and sodium hydroxide reacting and forming salt and water} & \text{Chemical Change} \\
\hline
6 & \text{Digesting food into nutrients} & \text{Chemical Change} \\
\hline
7 & \text{Melting ice into water} & \text{Physical Change} \\
\hline
8 & \text{Acid rain dripping onto limestone and making carbon dioxide gas} & \text{Chemical Change} \\
\hline
9 & \text{Breaking a glass into pieces} & \text{Physical Change} \\
\hline
10 & \text{Hydrogen peroxide decomposing into oxygen gas and water} & \text{Chemical Change} \\
\hline
\end{array}
\]
\boxed{
\begin{array}{|c|l|c|}
\hline
\text{No.} & \text{Process} & \text{Type} \\
\hline
1 & \text{Heating water into steam} & \text{Physical Change} \\
\hline
2 & \text{Milk going sour} & \text{Chemical Change} \\
\hline
3 & \text{Dissolving sugar in water} & \text{Physical Change} \\
\hline
4 & \text{Iron rusting} & \text{Chemical Change} \\
\hline
5 & \text{Hydrochloric acid and sodium hydroxide reacting and forming salt and water} & \text{Chemical Change} \\
\hline
6 & \text{Digesting food into nutrients} & \text{Chemical Change} \\
\hline
7 & \text{Melting ice into water} & \text{Physical Change} \\
\hline
8 & \text{Acid rain dripping onto limestone and making carbon dioxide gas} & \text{Chemical Change} \\
\hline
9 & \text{Breaking a glass into pieces} & \text{Physical Change} \\
\hline
10 & \text{Hydrogen peroxide decomposing into oxygen gas and water} & \text{Chemical Change} \\
\hline
\end{array}
}
Definitions Recap:
- Chemical Change: A chemical reaction occurs, and new products are formed. The identity of the matter changes.
- Physical Change: Matter changes form but its identity does not change.
Analysis of Each Item:
1. Heating water into steam
- Explanation: When water is heated, it changes from a liquid to a gas (steam). No new substances are formed; it's just a change in state.
- Type: Physical Change
2. Milk going sour
- Explanation: Milk going sour involves bacteria breaking down lactose into lactic acid, forming new substances.
- Type: Chemical Change
3. Dissolving sugar in water
- Explanation: Sugar dissolves in water, forming a solution. No new substances are created; it's just a mixing of molecules.
- Type: Physical Change
4. Iron rusting
- Explanation: Rusting is the oxidation of iron, where iron reacts with oxygen and water to form iron oxide (rust). New substances are formed.
- Type: Chemical Change
5. Hydrochloric acid and sodium hydroxide reacting and forming salt and water
- Explanation: Hydrochloric acid (HCl) reacts with sodium hydroxide (NaOH) to form sodium chloride (salt) and water. This is a neutralization reaction, forming new substances.
- Type: Chemical Change
6. Digesting food into nutrients
- Explanation: Digestion involves breaking down complex molecules in food into simpler molecules (e.g., proteins into amino acids). New substances are formed.
- Type: Chemical Change
7. Melting ice into water
- Explanation: Ice melting into water is a change in state from solid to liquid. No new substances are formed.
- Type: Physical Change
8. Acid rain dripping onto limestone and making carbon dioxide gas
- Explanation: Acid rain (containing sulfuric or nitric acid) reacts with calcium carbonate in limestone to form calcium sulfate/nitrate and carbon dioxide gas. New substances are formed.
- Type: Chemical Change
9. Breaking a glass into pieces
- Explanation: Breaking glass into pieces is a physical change in shape, but the glass itself remains the same material.
- Type: Physical Change
10. Hydrogen peroxide decomposing into oxygen gas and water
- Explanation: Hydrogen peroxide (H₂O₂) decomposes into water (H₂O) and oxygen gas (O₂). This is a chemical reaction forming new substances.
- Type: Chemical Change
Final Answer:
\[
\begin{array}{|c|l|c|}
\hline
\text{No.} & \text{Process} & \text{Type} \\
\hline
1 & \text{Heating water into steam} & \text{Physical Change} \\
\hline
2 & \text{Milk going sour} & \text{Chemical Change} \\
\hline
3 & \text{Dissolving sugar in water} & \text{Physical Change} \\
\hline
4 & \text{Iron rusting} & \text{Chemical Change} \\
\hline
5 & \text{Hydrochloric acid and sodium hydroxide reacting and forming salt and water} & \text{Chemical Change} \\
\hline
6 & \text{Digesting food into nutrients} & \text{Chemical Change} \\
\hline
7 & \text{Melting ice into water} & \text{Physical Change} \\
\hline
8 & \text{Acid rain dripping onto limestone and making carbon dioxide gas} & \text{Chemical Change} \\
\hline
9 & \text{Breaking a glass into pieces} & \text{Physical Change} \\
\hline
10 & \text{Hydrogen peroxide decomposing into oxygen gas and water} & \text{Chemical Change} \\
\hline
\end{array}
\]
\boxed{
\begin{array}{|c|l|c|}
\hline
\text{No.} & \text{Process} & \text{Type} \\
\hline
1 & \text{Heating water into steam} & \text{Physical Change} \\
\hline
2 & \text{Milk going sour} & \text{Chemical Change} \\
\hline
3 & \text{Dissolving sugar in water} & \text{Physical Change} \\
\hline
4 & \text{Iron rusting} & \text{Chemical Change} \\
\hline
5 & \text{Hydrochloric acid and sodium hydroxide reacting and forming salt and water} & \text{Chemical Change} \\
\hline
6 & \text{Digesting food into nutrients} & \text{Chemical Change} \\
\hline
7 & \text{Melting ice into water} & \text{Physical Change} \\
\hline
8 & \text{Acid rain dripping onto limestone and making carbon dioxide gas} & \text{Chemical Change} \\
\hline
9 & \text{Breaking a glass into pieces} & \text{Physical Change} \\
\hline
10 & \text{Hydrogen peroxide decomposing into oxygen gas and water} & \text{Chemical Change} \\
\hline
\end{array}
}
Parent Tip: Review the logic above to help your child master the concept of physical changes in matter worksheet.
