Chemistry teacher team of SMAN 1 Tarakan

Based on Prof. Effendy material

understand the classification of matter. understand the difference of element,

mixture and compound. differentiate between physical and

chemical properties of substances. differentiate between physical and

chemical changes of matter.

Matter

Pure substance Mixture

Elements Compounds

HomogeneousHeterogeneous

(fixed compositionand properties)

(can bedecomposedby chemical

reaction)

(can not bedecomposed)

(nonuniformcomposition)

(uniformcomposition)

Chemicallyseparable into

Combine chemically to

form

Physicallyseparable into

Heterogeneous mixture:

A mixture with a composition that varies from point to point

Examples: mayonnaise chocolate chip cookies concrete

Homogeneous mixture:

A mixture with a composition that doesn’t vary from point to point

Homogeneous mixture is also called solution

Examples: Mixture of water and alcohol Mixture of table salt and water Mixture of sugar and water

Mixture of iron and sulfur may be separated by using a magnet

Mixture of two liquids with different boiling points such as mixture of water and alcohol may be separated by distillation

Mixture of colored substances such as the components of a green ink may be separated by column chromatography

Mixture of two crystalline substances from a solution such as barium chromate, BaCrO4, and strontium chromate, SrCrO4, may be separated by fractional crystallization.

Barium chromate is less soluble in water than strontium chromate. Barium chromate crystallizes before strontium chromate.

Most of substances in the world are compounds.

What is compound?

Compound is a pure substance that is formed when atoms of two or more

different elements combine and create a new material with properties completely unlike those of its constituent elements.

Formation of a compound from its elements involves a

chemical change, called chemical reaction

For example:

Sodium (a soft, silvery metal) combines with chlorine (a toxic, yellow-green gas) to give sodium chloride (salty table salt)

Na(s) + Cl2(g) 2NaCl(s)

Hydrogen (colorless gas) combines with oxygen (colorless gas) to give water (colorless liquid).

2H2(g) + O2(g) 2H2O(l)

In the compound, the elements no longer have the same

properties they had before they were combined.

The properties of H2O is different from the properties of

H2 and O2.

A compound is written by giving its chemical formula, which lists the symbols of the individual constituent elements and indicates the number of atoms of each element with subscript.

Chemical formula

of compound

Constituent elements

H2O

HCl

H2SO4

NH3

Two hydrogen and one oxygen atomsOne hydrogen and one chlorine atomsTwo hydrogen, one sulfur, and four oxygen atomsOne nitrogen and three hydrogen atoms

The basic object of chemistry is elements.

What is an element?

An element is a fundamental substance that can’t be chemically

changed or broken down into anything simpler.

How many presently known elements?

115 elements

90 natural elements

25 artificially elements produced using high energy accelerators

How do chemists represent an element?

By using one-, two-, or three-letter symbols of an element

Examples:H for hydrogen N for nitrogenAl for aluminumMg for magnesiumUun for ununnilium

1

2

3

4

5

6

7

Per

iod

(1)

(2)

(3) (4) (5) (6) (7) (8) (9) (10) (11) (12)

(13) (14) (15) (16) (17)

(18)

GroupIA

IIA

IIIB VBIVB VIBVIIIB

VIIB IB IIB

VIIIA

IVAIIIA VA VIIAVIAH

Na

Li

K

Cs

Rb

Be

Ca

Mg

Sr

Ra

Ba

Fr

Sc

Y

Ac

La

Ti

Zr

Rf

Hf

V

Nb

Db

Ta

Cr

Mo

Sg

W

Mn

Tc

Bh

Re

Fe

Ru

Hs

Os

Co

Rh

Mt

Ir

Ni

Pd

Uun

Pt

Cu

Ag

Uuu

Au

Zn

Cd

Uub

Hg

B

Al

In

Ga

Tl

C

Si

Sn

Ge

Uuq

Pb

N

P

Sb

As

Bi

O

S

Te

Se

Uuh

Po

F

Cl

I

Br

At

Ne

Ar

Xe

Ke

Uuo

Rn

He

Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

Properties can also be classified as either physical or chemical, depending on whether the property involves a change in the chemical makeup of substance Physical properties:Characteristics that do not involve a change in a sample’s chemical makeup

Examples of physical properties:Melting pointBoiling pointFreezing point

Melting point of ice and boiling point of water are physical properties because melting and boiling cause the water to change only in form or phase, but do not in chemical makeup

Chemical properties:

Characteristics that do involve a change in a sample’s chemical makeup

Example:

Rusting of iron

Rusting of iron is a chemical property, because iron combines with oxygen and moisture from the air to give the new substance

Some Examples of Physical and Chemical Properties

Physical Properties Chemical properties

TemperatureColorMelting pointElectrical conductanceAmountOdorSolubilityHardness

Rusting (of iron)Combustion (of gasoline)Tarnishing (of silver)Hardening (of cement)Decomposition (of sugar)