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