1. Chapter 7 Foundations of Chemistry

2. Matter and Volume Matter- Anything that has mass and takes up space.
Everything in the universe that you can see is made up of matter.
Volume- The amount of space taken up, or occupied, by an object.
Because objects have volume, they cannot occupy the same space at the same time.

3. Liquid Volume Units for Liquid Volume Measuring Liquid Volume L mL cm3
Use graduated cylinder– more accurate
Meniscus – the curve at a liquids surface
Read liquid measurements from the bottom of the meniscus.

4. Solid Volume Regularly Shaped Objects Units for solids
cm3 units (having 3 sides)
Volume = length (l) x width (w) x height (h)
Example: What is the volume of a block that measures:
Length: 3 cm Width: 5 cm Height: 7 cm

5. Solid Volume Irregularly Shaped Objects Same units as above
Use water displacement method.
Submerge object in a known amount of water and read the level change.
1 mL = 1 cm3
Ex. Graduated cylinder has 25.0 mL of water in it. After Tom places a paper clip in it, the water level rises to 28.6 mL. What is the paper clips volume?

6. Matter and Mass Mass– the amount of matter in an object.
The more matter in the object, the greater the mass
Mass of an object is the same regardless of the object’s location in the universe.
Mass vs. Weight
Mass and weight do NOT have the same meaning.
Weight– the measure of gravitational force exerted on an object.
Will change with location in the universe

7. Difference Between Mass and Weight
Measure of the amount of matter in an object
Always the same regardless of location in universe
Measured using a balance
Expressed in grams
WEIGHT
Measure of gravitational force on an object
Changes based on location in the universe
Measured using a scale
Expressed in Newtons (N)

8. 7.2 Physical Properties
A Physical Property of matter can be observed or measured without changing the matter’s identity.
Examples:
color
Melting and boiling points
mass
Conduct electricity
Strength
Flexibility
State – solid, liquid, or gas
Density – the amount of mass in a given volume
Solubility
Ductility – ability to be draw into wires
Malleability – ability to be hammered into sheets

9. Physical Properties Viscosity - A liquid’s resistance to flow
Malleable– Can be hammered into thin sheets

10. Density
Density is a physical property that describes the relationship between mass and volume.
Density- the amount of matter in a given space or volume.
Basketball vs. bowling ball.
They both are the same size, but the bowling ball has more mass.
Since it has more mass, it has a greater density

11. Density Continued Denser liquids go to the bottom of the container.
Think of vinegar and oil salad dressing
Density of solids.
Would you rather carry 1kg of feathers or 1kg of lead?
The lead would be much smaller to carry around.
An object will float on water if it is less dense than water
The object will sink if it is more dense than water.

12. Density Continued
To find density, you must first measure the mass and volume of the object.
The formula is:
Density = mass D = m
volume V
The unit will be g/cm3 . You may also see kg/m3 or kg/L

13. Density Continued
What is the density of an object whose mass is 25g and whose volume is 10 cm3?
Suppose you have a lead ball whose mass is 454 g and density is g/cm3. What is the volume of the ball?

14. Density Continued
What is the mass of a 15 mL sample of mercury with a density of g/mL?
A graduated cylinder contains 25 mL of water. When a 4.5 g paper clip is dropped into the water, the water level rises to 36 mL. What is the density of the paper clip?

15. 7.3 Physical Changes Physical changes do not form new substances.
Physical change- A change that affects one or more physical properties of a substance.
Examples include:
silver shaped into jewelry
Cutting a piece of wood
Tearing a piece of paper
Dissolving sugar in water
Change of state

16. 7.4 Chemical Properties & Changes
Chemical Properties -Describes matter based on its ability to change into new matter that has different properties.
Wood is flammable. (Ability to burn)
Reactivity- the ability of two or more substances to combine.
Iron combines with water and oxygen to form rust.

17. Chemical Changes
Chemical change- Occurs when one or more substances are changed into new substances that have new and different properties.
When you bake a cake, you combine flour, sugar, eggs, and several other ingredients. The product is the cake. You cannot unbake the cake and return to the original ingredients.

18. Signs of a Chemical Change
Several signs indicate a chemical change has taken place. These include:
Change in color
Change in odor
production of heat
fizzing and foaming, or bubbling
or formation of a precipitate (solid)
When you bake a cake you smell it baking, you see it browning, and when you cut it open you can see pockets of gas.

19. Color Change
Copper will form a patina when exposed to moist air

20. Production of a Gas
Carbon Dioxide gas forms when baking soda is mixed with vinegar.

21. Formation of a Precipitate
Curds in cottage cheese form when acid is added to milk

22. Composition
Composition- The type of matter that makes up the object and the way that the matter is arranged in the object.
Physical changes will not change the composition of the material.
Chemical changes will change the composition of the material.