Chemistry of Life

Matter• Anything that has mass and takes up

space.

3 types of matter:

a). Solid

b). Liquid

c). Gas

Solids

Any substance that has a definite shape and definite volume.

LIQUID

Any substance that has a definite volume but not a definite shape. It takes the shape of its container.

Gas

Any substance that has no definite shape or definite volume.

Physical Change

Changing the physical properties of a substance without changing the substance itself.

Physical Properties

The characteristics of a substance that you can observe with the senses.

They include:

shape

volume

color

odortexture

ATOMSThe smallest particle of matter that can exist

and still have the properties of a particular kind of matter.

Atoms are composed of:

1. Nucleus – central part of the atom

2. Protons – positively charged particles (+)

3. Neutrons – uncharged particles

4. Electrons – negatively charged particles (-)

electrons

protons

neut

rons

orbit

Orbits (Energy Levels)

A region around the nucleus in specific energy levels.

There are 7 energy levels known to date.

1st energy level holds a maximum of 2 electrons.

2nd energy level holds a maximum of 8 electrons.

3rd energy level holds a maximum of 18 electrons.

Elements

http://www.chemsoc.org/viselements/pages/page3.html

Substances that are made up entirely of atoms of the same kind and cannot be divided into simpler substances by ordinary chemical means.

Symbol – a shorthand method of representing an element.

Atomic Number - # of protons in the nucleus of the element.

Atomic Mass Number - # protons + # of neutrons

# protons = # of electrons; atoms are electrically neutral

How many protons, electrons, and neutrons are found in the following atoms?

Calcium –

protons –

electrons –

neutrons -

Ca

20

20

20

Iodine –

protons –

electrons –

neutrons -

I

53

53

74

Gold –

protons –

electrons –

neutrons -

Au

79

79

118

Molecule – the smallest part of a substance that has all the chemical properties of that substance. Made up of atoms of the same or different kinds of atoms.

Compound – matter made up of 2 or more atoms that are chemically combined from different elements.

H2O NH3 O2 2NaCl 4H2 CO2 He

Chemical (Molecular) Formulas

Shows the kind and number of atoms in a molecule or compound.

Ex: H2 - hydrogen gas H – symbol 2 – subscript 2 atoms of Hydrogen

2H2O C6H12O6

Chemical Change

a) Always uses or gives off energy

b) Results in a new substance

Ex: H2 + O2 2H2O

Na + Cl NaCl

Mixtures – substances that are combined but not changed chemically.Ex: cereal & milk

vegetable saladHow could a mixture of salt and water be separated?

2 types: a) homogeneous – one in which the substances are evenly distributed. b) heterogeneous – the substances are not evenly distributed.

Mixtures

Solution – a mixture that is formed when the molecules of one substance mix evenly with those of another substance.

ex: Kool-Aid lemonade

Suspension – a heterogeneous mixture containing particles distributed with a liquid, gas, or solid.

ex: soil & water RBC & blood

Colloid – a mixture composed of particles dispersed in a medium

ex: gelatin (partly solid & partly liquid)

How is fog a colloid?

Acids & Bases

Acid – a chemical that produces hydrogen ions in a water solution.

Ex: HCl H2SO4

Base – a chemical that produces hydroxide ions in a water solution.

Ex: NaOH

pHpH scale – scale for measuring how acidic or basic various

solutions are.

a. Ranges from 0 to 14

b. a solution w/a pH of 7 is neutral

c. a solution w/a pH below 7 (0 to 6.9) is acidic

d. a solution w/a pH above 7 (7.1 to 14) is basic

Ex: stomach acid

vinegar

milk

blood

soap

1

3

6.5

7.3

10