There are three phases that are made up of microscopic particles and all of them behave differently from each other.

- Solids: Are tightly packed together and vibrate, but they do not move from place to place
- Liquids: Are close together, but do not have a regular arrangement. They vibrate and are able to move about
- Gases: Are well separated, vibrate, and move freely at high speeds

Condensed states of matter: Liquids and solids

State of Matter | Characteristic | Explanation |
---|---|---|

Solid |
Retains a fixed volume and shape | Rigid - The particles lock into place |

Not easily compressible | Little free space between particles | |

Does not flow easily | Rigid - The particles cannot move/slide past each other | |

Liquid |
Assumes the shape of the container which it occupies | Particles move/slide past each other |

Not easily compressible | Little free space between particles | |

Flows easily | Particles can move/slide past each other | |

Gas |
Assumes the shape and volume of the container | Particles can move past each other |

Compressible | Lots of free space between particles | |

Flows easily | Particles can move past each other |

For a fun, interactive simulation to help you get a better understanding of the states of matter, visit PhET Interactive Simulations by the University of Colorado Boulder.

There are three systems of measurement widely used for temperature:

- Celsius scale - used in physical sciences
- Kelvin scale - used in physical sciences
- Fahrenheit scale - used in many engineering sciences

*Note: The size of the temperature unit (degree) is the same for Kelvin and Celsius scales. The difference is the zero points.*

**Conversions:**

Temperature (Kelvin) = temperature (Celsius) + 273.15

or

Temperature (Celsius) = temperature (Kelvin) - 273.15

*Example:*

Convert 400.0 K to the Celsius scale.

400.00 K - 273.15 = 126.85 °C

Helpful Tip:

Kelvin does not use a degree symbol for its unit unlike Celsius and Fahrenheit; it is symbolized by the letter K.

The degree size and zero points are different when considering Fahrenheit. As seen in the illustration above, The degree size for Fahrenheit is 180° and 100° for Celsius. So, the unit factor is:

180 °F 9 °F

------- or -------

100 °C 5 °C

This is because 180 ÷ 100 = 1.8 and in fraction form that is 9/5. You will also have to use the reciprocal depending on the direction that is needed.

Now, for the difference in zero points. To obtain the temperature in Celsius, you must subtract 32 °F from the given temperature in Fahrenheit and then multiply the unit factor to adjust for the difference in degree size.

5 °C

(*T*_{F} - 32 °F) X ------- = *T*_{C}

9 °F

As you can see in this equation, the reciprocal was used.

If the degree is needed in Fahrenheit and you have Celsius, then the following equation is used.

9 °F

*T*_{F} = *T*_{C} X ------- + 32 °F

5 °C

*Example:*

Convert 98.6 °F to the Celsius and Kelvin scales.

First, convert to Celsius:

5 °C

(98.6 °F - 32 °F) X ------- = 37.0 °C

9 °F

Next, convert the Celsius answer you just obtained to the Kelvin scale:

*T*_{K} = *T*_{C} + 273.15

*T*_{K} = 37.0 °C + 273.15

*T*_{K} = 310.2 K

**Density: **A property of matter used as an "identification tag" for a substance - the mass of the substance per unit volume of the substance.

mass

Density = -------------

volume

Compound |
Density in g/cm^{3} at 20 °C |
---|---|

Chloroform | 1.492 |

Diethyl ether | 0.714 |

Ethanol | 0.789 |

Isopropyl alcohol | 0.785 |

Toluene | 0.867 |

*Example:*

Identify the unknown liquid. 25.00 cm^{3} of the substance has a mass of 19.625 g at 20 °C. Use the chart on the right to solve for what the unknown liquid could possibly be.

The first thing needed, is to find the density of the unknown liquid:

mass 19.625 g

Density = ------------- = ----------------------- = 0.7850 g/cm^{3}

volume 25.00 cm^{3 }

The density obtained matches with the density of isopropyl alcohol.

*Note: Ethanol is also very close and you would need to run more tests in order to ensure that isopropyl alcohol is the correct unknown liquid.*

Substance |
Physical State |
Density (g/cm^{3}) |

Oxygen | Gas | 0.00133 |

Hydrogen | Gas | 0.000084 |

Ethanol | Liquid | 0.789 |

Benzene | Liquid | 0.880 |

Water | Liquid | 0.9982 |

Magnesium | Solid | 1.74 |

Salt (sodium chloride) | Solid | 2.16 |

Aluminum | Solid | 2.70 |

Iron | Solid | 7.87 |

Copper | Solid | 8.96 |

Silver | Solid | 10.5 |

Lead | Solid | 11.34 |

Mercury | Liquid | 13.6 |

Gold | Solid | 19.32 |

FUN FACTS:

The liquid in your car's lead storage battery changes density when the sulfuric acid is consumed as the battery discharges. If the battery falls below a certain amount, the battery will have to recharge.

You can determine the amount of antifreeze, which tells you the level of protection against freezing in the cooling system of your car.

The center of a black hole (the singularity) is infinitely dense.

Saturn has the lowest density of all the planets in our solar system. Saturn has a density of 0.687 g/cm^{3} which is less than water. So, if you have a large enough pool filled with water, Saturn will float!

Silver has a density of 10.5 g/cm^{3} and gold has a density of 19.3 g/cm^{3}. Which would have a greater mass, 5 cm^{3} of silver, or 5 cm^{3} of gold?

Silver: mass mass = density X volume Gold: mass = (19.3 g/cm Answer: gold has more density. |

One of the body's responses to an infection or injury is to elevate its temperature. A certain flu victim has a body temperature of 102 °F. What is the temperature on the Celsius scale?

Converting °F to °C 5 °C 5 °C Answer: 38.9 °C |

An irregularly shaped stone was lowered into a graduated cylinder holding a volume of water equal to 2.0 mL. The height of the water rose to 7.0 mL. If the mass of the stone was 25 g, what was its density?

You must find the difference in the volume of water from the initial point to after the stone was dropped. 25 g Answer: density = 5 g/mL |

Convert -196 °C to the Kelvin scale.

Temperature (Kelvin) = temperature (Celsius) + 273.15 Answer: |

Please note that at 2:15, the question being asked isn't complete until after the answer is provided.

**Heat capacity: **The amount needed to raise the temperature of an object 1ºC. This depends on mass and composition.

*Example:
It will take more heat to increase the temperature of a large pot of water than a small cup of water.
It will take more heat to increase the temperature of water than it will metal.*

*Comprehension Question:
Which has a higher heat capacity; water or gold? (Highlight box to reveal answer)*

Water will have a higher heat capacity. Gold (a metal) is a good conductor of heat and would have a lower specific heat. |

**Specific Heat Capacity (C): **The amount of heat it takes to raise the temperature of 1 g of a substance 1°C.

* q cal or J
C = ------------- = -------------------
m*Δ

In this video by Melissa Maribel, you will learn how to figure out the heat and specific heat capacity in two common calorimetry problems.