Chem 2A Chapter 3 1 Essay

Submitted By baileyedmundson
Words: 1010
Pages: 5

Prac%ce!

A. (4 x 972) + (76.4 x 29.3) – (12 x 7) =

B. (72.67 – 72.63) x (4.2694)

=

(9.72 + 0.01) C. 4.1 x 10-­‐3 – 6.9 x 10-­‐2

=

7.2 x 10-­‐6 + 8.943 x 104

D. 10,000,000 x 0.0003845 x 4.55

=

4.331 x 10-­‐6

Prac%ce!

• 761.2 mm to cm

• The element bromine at room temperature is a liquid with a density of 3.12 g/mL. Calculate the mass of 0.125 L of bromine.

• Iron has a denisty of 7.87 g/cm3. If 52.4 g of iron is added to 75.0 mL of water in a graduated cylinder, to what volume reading will the water level in the cylinder rise?

MaXer

• Anything that has mass and occupies space

States of MaXer: Solid

• Rigid • Fixed shape and volume

States of MaXer: Liquid • Has definite volume

• Takes shape of container

States of MaXer: Gas







No fixed volume or shape Takes the shape and volume of its container Compressible

Spacing: far apart

Examples: Air, helium, oxygen, etc.

Elements and Compounds

• Element: substance that can’t be broken down into other substances by chemical methods

• Only one kind of atom

• Ex. Oxygen (O) , hydrogen (H)

• Compound: substance composed of a given combo of elements that can only be broken down by chemical methods

• Contains atoms of different elements

• Has same combo of atoms

• Ex. Water (H20) carbon dioxide (CO2)

Elements and Compounds • Which of the following are compounds?

• Al, NaOH, MnO2, Fe • Which of the following is an element?

• salt, water, earth, oxygen

Mixtures and Pure Substances

• Mixture:

• variable composi%on

• Can be separated into pure substances (elements &/or compounds)

• Ex. Wood, wine, coffee

• Mixture can be:

• Homogeneous-­‐ SAME throughout (solu%on)

• Heterogeneous – DIFFERENT proper%es from those of other regions

Mixtures and Pure Substances

• Homogenous mixture: • Air around you

• Table salt • Petroleum

• Gasoline

• Heterogeneous mixture • Cereal

• Oil and vinegar dressing

• Sand s%rred in water

Physical Proper%es

• Can be observed, measured WITHOUT CHANGING IDENTITY of substance • Doesn’t change the composi%on

• i.e. odor, color, volume, physical state (s, l, g), density, mel%ng point, boiling point

Physical Changes • Changes that do not change the chemical composi%on of substance

• i.e. changing states à boiling or freezing water • Example:

• cukng…