Chemistry worksheet on phase changes, freezing, and melting points, including a chart, phase diagram, and temperature conversions.

Let's solve each part of Worksheet #C55: Phase Changes, Freezing and Melting Points step by step.

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1. The 4 States of Matter (Complete the chart)

We need to fill in the following for each state:

- Has definite volume?
- Takes the shape of its container?
- Hot enough to lose its electrons?

| State | Has definite volume? | Takes the shape of its container? | Hot enough to lose its electrons? |
|---------|------------------------|------------------------------------|-----------------------------------|
| Solid | Yes | No | No |
| Liquid | Yes | Yes | No |
| Gas | No | Yes | No |
| Plasma | No | Yes | Yes |

#### ✔ Explanation:
- Solid: Particles are tightly packed; fixed shape and volume.
- Liquid: Particles flow; definite volume but take container shape.
- Gas: Particles spread out; no definite shape or volume.
- Plasma: Ionized gas where atoms have lost electrons due to high temperature (e.g., stars, lightning).

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2. Complete the diagram below, naming the changes

We have a triangle with three states: Solid, Liquid, and Gas.

We need to label the arrows showing phase changes.

```
Gas
/ \
/ \
/ \
/ \
Solid <------> Liquid
```

#### Labeling the arrows:

- Solid → Liquid: Melting
- Liquid → Solid: Freezing
- Liquid → Gas: Vaporization (or Boiling)
- Gas → Liquid: Condensation
- Solid → Gas: Sublimation
- Gas → Solid: Deposition

So the completed diagram should look like this:

```
Gas
/ \
Sublimation Condensation
/ \
/ \
/ \
Solid <-----> Liquid
Melting Freezing
```

(With "Vaporization" going from Liquid → Gas)

> Note: Sometimes "Boiling" is used instead of "Vaporization", but vaporization includes evaporation and boiling.

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3. Centigrade and Fahrenheit temperatures to memorize

Fill in the values:

| Description | °C | °F |
|-------------------------------------|--------|--------|
| i. Freezing point of water | 0 | 32 |
| ii. Standard room temperature | 20 | 68 |
| iii. Normal body temperature | 37 | 98.6 |
| iv. Boiling point of water | 100 | 212 |
| v. Absolute zero | -273.15| -459.67|
| vi. Freezing point of mercury | -38.8 | -37.8 |

#### ✔ Notes:
- Freezing point of water: 0°C = 32°F
- Room temperature: Typically around 20–22°C (~68–72°F); 20°C is standard for many textbooks.
- Body temperature: 37°C = 98.6°F
- Boiling point of water: 100°C = 212°F
- Absolute zero: -273.15°C = -459.67°F (lowest possible temperature)
- Freezing point of mercury: Mercury freezes at about -38.8°C, which is -37.8°F.

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✔ Final Answer Summary:

#### 1. Chart:

| State | Has definite volume? | Takes the shape of its container? | Hot enough to lose its electrons? |
|---------|------------------------|------------------------------------|-----------------------------------|
| Solid | Yes | No | No |
| Liquid | Yes | Yes | No |
| Gas | No | Yes | No |
| Plasma | No | Yes | Yes |

#### 2. Diagram Labels:

- Solid → Liquid: Melting
- Liquid → Solid: Freezing
- Liquid → Gas: Vaporization
- Gas → Liquid: Condensation
- Solid → Gas: Sublimation
- Gas → Solid: Deposition

#### 3. Temperature Conversions:

| Description | °C | °F |
|-------------------------------------|----------|----------|
| i. Freezing point of water | 0 | 32 |
| ii. Standard room temperature | 20 | 68 |
| iii. Normal body temperature | 37 | 98.6 |
| iv. Boiling point of water | 100 | 212 |
| v. Absolute zero | -273.15 | -459.67 |
| vi. Freezing point of mercury | -38.8 | -37.8 |

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✔ This worksheet covers key concepts in physical science: states of matter, phase changes, and temperature benchmarks. Let me know if you'd like a printable version or further explanation!