Science is a systematic or organized body of knowledge obtained through observation and experimentation.

Chemistry is a branch of science that deals with the study of matter(properties, structure, composition, changes and principles/laws that govern changes in matter).

Measurement SI Units commonly used

Length Meter (m) Meter (m)

Mass Kilogram (kg) Gram (g)

Volume Cubic meter(m3) Liter (l) , ml.

Amount of Substance

Mole(mol) Mole(mol)

Temperature Kelvin (K) Celsius( ◦ C)

1ml=1cm3 (or cc.); 1Liter = 1000 ml.=1000 cm3 (or cc.) = 1dm3

* 273 K = 0 ◦ C = 32◦ F

Prefix Symbol Meaning Tera T 1012 Giga G 109 Mega M 106

Kilo k 103

Deci d 10-1 or 1/10

Centi c 10-2 or 1/100

Milli m 10-3 or 1/1000

Micro u 10-6 1/1000,000

Nano n 10-9

Pico p 10-12

Temperature:

◦ F = 9 ◦ C + 32; 5

◦ C = 5 ( ◦ F - 32) 9

K= 273 + ◦ C

Density: D(g/ml) = Mass/Volume ; D (g/L ) = M / V

for solids and liquids for gas

Accuracy tells how close a measurement is to the true value.

Precision tells how close two or more measurements agree with one another.

Accuracy – how close a measurement is to the true valuePrecision – how close a set of measurements are to each other

Accurate &Precise Precise but

not accuratenot precise &

not accurate

Properties of Matter

Properties –qualities or characteristics by which a given substance is identified.

Physical Properties qualities that can be observed with the senses,without changing the composition of the susbstance. Ex. colors, shapes, size

Chemical Properties

qualities that can be observed after alteration of composition of the substance

Ex: iron rust, hydrogen is flammable

Extrinsic or Extensive Properties• are properties that depend on the amount of the

substance in a sample • Ex: volume, length, mass

Intrinsic or Intensive Properties do not depend on the amount of substance ex.

density, boiling pt. melting pt

Changes of Matter

Physical Change change in size, shape, physical state, no change in nature or compositon.Ex: freezing of water, pulverizing salt distillation of wine

Chemical Change • change in the compositon of the

substance • a new substance is formed.• ex iron nail (Fe) → rust (Fe2O3) • charcoal (C) Δ CO2

• Fermentation of fruit juice

Molecules = aggregate of two or more atoms held by a chemical bond.

I. Diatomic molecule is composed of two atoms.

a. with two similar atoms (element) ex: H2, N2, Cl2, F2

b. with two different atoms (compound) ex. HI, HF, CO, HCl

2. Polyatomic molecule is composed of three or more atoms.

a. with three similar atoms ex: O3 b. with three different atoms ex: HCN,

NH3, CaCO3, C6H12O6

Ion = an atom or a group of atoms that has a positive(+) or negative(-) charge.

a. Cations are positively charged ions ( formed when there is a loss of one or more

electrons) ex: Na + , Ca +2, Al+3

Na◦atom 11p +11 e- = O; Na+cation11p + 0 e- = +1

b. Anions are negatively charged ions (formed when there is a gain of one or more

electrons) ex: Cl- , O -2

Cl◦ atom 17p + 17 e- = o; Cl- anion17p + 18e- = -1

Mass number (A) = the total number of protons + number of neutrons

Atomic number (Z) = the number of protons in the nucleus of an atom.

A X

Z

12

6 C17

9 Cl

Isotopes of Hydrogen

2 1 H

1

1 H3

1 H

Protons = _

Neutrons=_

Protons = _

Neutrons=_Protons = _

Neutrons =_

Isotopes of Hydrogen

2 1 H

1

1 H3

1 H

Protons = 1

Neutrons= 0

Protons =1

Neutrons= 1Protons = 1

Neutrons = 2

Isotopes of Uranium

235 92 U

234

92 U238

92 U

Protons = 92

Neutrons=

Protons =92

Neutrons=Protons = 92

Neutrons =

Isotopes of Carbon and % Abundance

13 6C

12

6 C

Protons = 6

Neutrons= 6 Protons = 6

Neutrons= 7

% abundance =98.89%% Abundance = 1.11%

Computations:12 x 0.9889 =11.866813 x 0.0111 = 0.1443 12.0111 atomic weight 12. atomic mass (mass no.)Mass no.- the whole no. nearest to the exact

atomic weight

Atomic Structure : Atom- basic unit of an element that can enter into a chemical reaction, retains the identity of element

Electron (discovered by Joseph John Thomson) is negatively charge(-) particle

Neutron (discovered by James Chadwick) is electrically neutral particle.

Proton and atomic nucleus (by Ernest Rutherford) positively charged(+) particle.

Chemical formula represents the composition of one molecule or ionic compound in terms of chemical symbols. a. Molecular formula shows the actual number of atoms of elements in a molecule.

ex: C6H 12O6 ( sucrose), C6H6 (benzene ) ,C2H2 (acetylene) .

b.Empirical formula gives the simplest whole number ratio of atoms of elements in a molecule ex: C H2 O ( sucrose), C H (benzene ) , C H (acetylene)

c.Lewis formula shows the valence electrons of atoms of elements in a molecule. .. .. ..

ex: H: O : O: H (hydrogen peroxide) H: O :H (water) .. .. .. d. Structural formula shows the binding of atoms of elements in a molecule.

ex: H-O –O -H (hydrogen peroxide) H- O -H (water)

Electronic Structure of Atoms

Aufbau PrincipleAtomic orbitalsElectronic configurationOctet RuleHund’s Rule

Reduction Oxidation Reaction

Molecular Equation (Valence Change Method)NaNO2+ K2Cr2O7 + H2SO4 = NaNO3 +K2SO4 + Cr2 (SO4) 3+ H2O

Ionic Equation (Valence Change Method) NO2 + Cr2O7 + H + = NO3 -1 + Cr + H2O

Half Reaction or Ion-electron method NO2

-1 = NO3 -1

Cr2O7 -2 = Cr+3

+3

-2 -1

Redox

Balance the eq. using Valence change or Ion electron method . Answer #1-10MnO4

-1 + ClO2

-1 +H2O = MnO2 + ClO4 -1 + OH-

___1. Oxidation no. of Mn in MnO4 -1

___2. Oxidation no. of Cl in ClO 4 -1

___3. electron lost/mole ___9. coefficient of ClO2-1

___4. electron gained/mole ___10. coefficient of MnO2

___5 Identify the OA___6. Which is the RA?___7. Which is the reduction product?___8. Which is the oxidation product?

Concentration Units

Molarity – moles of solute per liter of solutionM= moles solute moles = g solute liter of solution molar mass g solute M = molar mass liter solution

Normality – no of equivalents of solute per liter of solution

N = equivalents of solute liter of solution

g soluteN = eq wt liter of solution

molality - moles of solute per kg solvent g solute m = molar mass kg solvent

% by mass = mass solute X 100 mass of solution

Mole fraction solute (X2) = mole solute mole solution

Mole fraction solvent (X1) = mole solvent mole solution

Concentration Units

1.Calculate the % by mass of the solute in: a. 5.50 g NaBr in 78.2 g solutionb. 31.0 g KCl in 152.0 g water 2.A solution is prepared by mixing 62.5 ml C6H6 (MW 78g/mol) with 80.3 ml toluene(MW 92.0g/mol) density C6H6 0.867 g/ml

density C7H8 0.87 g/ml.