1. Investigation 2 September 16, 2014
Properties of Matter
Investigation 2
September 16, 2014

2. Background Information
Density is a property of matter that explains how much matter exists in a particular space.
Density depends on mass and volume
Formula:
Density = mass ÷ volume
The unit of measurement for density is g/cm³
Chemical reactivity: a chemical reaction that can occur when an element or compound is combined with another element or compound.
Examples: change in color or formation of gas (bubbles)

3. Chemical Reaction Experiment
Bill Nye Chemical Reaction

4. Relationships of Matter
Elements, Atoms, Molecules,
Compounds: molecules that contain 2 or more different atoms; a compound is still a molecule, its just a special kind because it has different atoms
Subatomic particles: the small particles that make up an atom and determine its properties.

5. Oxygen atoms may combine to form molecules and compounds
Oxygen atom is made up of smaller “subatomic” particles
The Element Oxygen

6. Every atom contains a “nucleus” containing the same number of the subatomic particles protons and neutrons in most cases
An atom’s nucleus is surrounded by a cloud of electrons that are present in the same number as protons as well
What is the atomic number of Sulfur? ______
The molecule Sulfur is a yellow solid (future use in Lab)
Sulfuric Acid is a liquid (future us in Lab)

7. How do I calculate density?
Let’s Practice!!!

8. Liquid volumes are reported as milliliters or liters
Solid volumes are reported as cubic centimeters (cm³) or cubic meters (m³)
Gases are reported as either cubic meters or liters
A cubic centimeter (cm ³) of volume is the same as a milliliter (ml) of volume
For example: 20 ml of a liquid in a graduated cylinder = 20 cm³ of volume

9. Other evidence of a chemical reaction includes:
formation of a solid when 2 liquids are mixed
light given off
sound is produced
change in odor
change in taste (we don’t use this in lab!!!)
change in pH
change in viscosity

10. Thinking About Investigation 2 Lab
Based on the density of the samples, do you know whether each substance is an element or compound?
Based on the properties investigated so far, do you know the identities of the substances?
Do any of the substances have the same physical properties?