Chemistry

Long quiz Chap 1 n 2

Chemistry

It is the study of matter, its properties, and the changes it undergoes.

Science Related Fields of chemistry

Technology, Medicine, Biochemistry, Energy

Matter

It is anything that has mass and takes up space

Classifying Matter

Atom

Classifying Matter

Molecules of an element

Classifying Matter

Molecules of a compound

Classifying Matter

Mixture of elements and a compound

States of matter

1) solid.

2) liquid.

3) gas.

Substance

It has distinct properties and a

composition that does not vary from sample to

sample.

elements and compounds.

Two types of substances

Atoms

building blocks of matter.

element

It is made of a unique kind of atom, but can be made of more than one atom of that kind.

compound

made of atoms from two or more different elements.

molecules.

groups of atoms

Oxygen percentage in the human body

65%

Oxygen in the earth’s crust

49.5%

5 elements

Make up 90% of the Earth’s crust by mass.

three elements

make up 90% of the human body mass!

Silicon percentage in the Earth’s crust

25.7%

Aluminum percentage in the Earth’s crust

7.5%

Iron percentage in the Earth’s crust

4.7%

Calcium percentage in the Earth’s crust

3.4%

Other percentage in the Earth’s crust

9.2%

Other percentage in the Human body

7%

Hydrogen percentage in the Human body

10%

Carbon percentage in the Human body

18%

symbol of carbon

C

symbol of fluorine

F

symbol of Hydrogen

H

symbol of Iodine

I

symbol of Nitrogen

N

Symbol of Oxygen

O

Symbol of Phosphorus

P

Symbol of Sulfur

S

Symbol of Aluminum

Al

Symbol of Bromine

Br

Symbol of Calcium

Ca

Symbol of Chlorine

Cl

Symbol of Helium

He

Symbol of Lithium

Li

Symbol of Magnesium

Mg

Symbol of Silicon

Si

Symbol of Copper

Cu

Symbol of Iron

Fe

Symbol of Lead

Pb

Symbol of Mercury

Hg

Symbol of Potassium

K

Symbol of Silver

Ag

Symbol of Sodium

Na

Symbol of Tin

Sn

Symbol of Calcium

means that the relative number of atoms of each element in the compound is the same in any sample.

The Law of Constant Composition (or The Law of Definite Proportions).

Mixtures

exhibit the properties of the substances that make them.

Two types of mixtures

heterogeneous, homogeneous

homogeneous mixture is also called

solution

Heterogeneous

made up of parts that are different, diverse, or not uniform

Homogeneous

being the same, uniform throughout, or made of similar parts

Physical properties

can be observed without changing a substance into another substance.

Chemical properties

only be observed when a substance is changed into another substance.

Intensive properties

independent of the amount of the substance that is present

Extensive properties

depend upon the amount of the substance present.

Physical changes

changes in matter that do not change the composition of a substance.

Chemical changes

result in new substance

3 types of mixture

– filtration

– distillation

– chromatography

Filtration

solid substances are separated from liquids and solutions

Distillation

uses differences in the boiling points of substances to separate a homogeneous mixture into its components

Chromatography

This technique separates substances on the basis of differences in the ability of substances to adhere to the solid surface, in this case, dyes to paper

Kinetic energy

is the energy of motion.

Formula of kinetic

KE = 1/2 mv²

Potential energy

an object depends on its relative position compared to other objects

Mass

is a measure of the amount of material in an object. SI uses the kilogram as the base unit. The metric system uses the gram as the base unit.

Length

a measure of distance. The meter is the base unit.

Temperature

In scientific measurements, the Celsius and Kelvin scales are most often used.

freezing point of water

0 degree Celsius

boiling point of water.

100 degree Celsius

k = degree Celsius + 273.15

Celsius to Kelvin conversion formula

Precision

measure of how closely individual measurements agree with one another.

Accuracy

refers to how closely individual measurements agree with the correct, or “true,” value.

Law of Constant Composition

Compounds have a definite composition. That means that the relative number of atoms of each element in the compound is the same in any sample.

Joseph Proust.

He discovered Law of Constant Composition

Law of Conservation of Mass

The total mass of substances present at the end of a chemical process is the same as the mass of substances present before the process took place.

Antoine Lavoisier.

He discovered Law of Conservation of Mass

Law of Multiple Proportions

If two elements, A and B, form more than one compound, the masses of B that combine with a given mass of A are in the ratio of small whole numbers.

John Dalton

he discovered this law while developing his atomic theory.

J. J. Thomson

He discovered Streams of negatively charged particles were found to emanate from cathode tubes, causing fluorescence.

charge/mass ratio of the electron

1.76 × 10^8 coulombs/gram (C/g).

Millikan Oil-Drop Experiment (Electrons)

Once the charge/mass ratio of the electron was known, determination of either the charge or the mass of an electron would yield the other.

Robert Millikan

He determined the charge on the electron in 1909

Radioactivity

is the spontaneous emission of high-energy radiation by an atom.

They studied Radioactivity

Marie and Pierre Curie also studied it.

Radioactive was first observed by

Henri Becquerel

Ernest Rutherford

He discovered Three types of radiation

a = particles (positively charged)

B = particles (negatively charged, like electrons)

Y = rays (uncharged

The Atom, Circa 1900

Also known as plum pudding model, put forward by

J. J. Thomson.

Discovery of the Nucleus

Ernest Rutherford shot (a) particles at a thin sheet of

foil and observed the pattern of scatter of the particles.

1–5 Å or 100–500 pm

Measurement of Atom

Charge of Proton

+1

Charge of Electron

-1

Atomic Number

the number of protons in the nucleus of an atom.

Isotopes

atoms of the same element with different masses