Ultimate Science Review

8/14/2019 Ultimate Science Review

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A.M.D.GULTIMATE SCIENCE REVIEW • JOSEPH SZYMBORSKI 1/25

ULTIMATE SCIENCE REVIEW436 AND 416

BY: JOSEPH SZYMBORSKI

TOPICS:• Dimensional Analysis

• Scientific Notation

• Properties

• Physical and Chemical Change

• Elements and Compounds

• Mixtures (Heterogeneous &Homogeneous)

• Philosophers and Scientists

• Electrostatics

• Protons, Neutrons and Electrons• Bohr-Rutherford Diagrams

• Cathode Ray Tube

• Radioactivity

• Copper Oxide Labs

• Percent Yield

• Names of the Elements (1-36)

• Isotopes

• Average Atomic Mass

• Chemical Reactivity

•Periodic Trends

• Metals, Non-Metals and Metalloids

• Four Families

• Molecules

• Balancing Equations

• Mole

• Stoichiometry

• Structures of Matter

• Nomenclature

• Magnetism

• Electromagnetism

• Conductors/Insulators

• Theory on I/V/R• Resistors

• Ohm's Law

• Req Series/Parallel/Combo

• Kirchoff Series/Parallel

• Power Equations

• Read a Hydrometer

• Heat

• Heat -> Electrical power

• Concentration / Solutions / Dilutions

• Acids, bases and salts• Indicators

• pH

DIMENSIONAL ANALYSIS:

• Dimensional Analysis can always (and should always) be solved in one line

• The focus is put on units (dimensions)

• You should start with a certain unit, and end by canceling out units via conversionfactors to end with the result that is asked of you

EX:The density of air is 0.00129 g/ml. What volume (in liters) will 1g of air occupy?

1ml 1cl 1dl 1L1g x ------- x -------- x -------- x ------- = 0.775193798 L

0.00129g 10ml 10cl 10dl




SCIENTIFIC NOTATION:

• Scientific Notation involves bringing a digit to only one number before the decimal and

adding it by powers of 10 to equate it.EX:

432.987 = 4.32987 x 102 0.00000567 = 5.67 x 10-6

PROPERTIES:

• There are two types properties: Characteristic and Non-Characteristic

• Characteristic properties are unique to only one substance

• Non-characteristic properties are shared between multiple substancesEX:

Property C OR NCHas a melting point of -77.7oC C

Is colorless NC

Has a density of 0.76 g/L C

Reacts with HCl (g) to produce a whitesmoke

C

In solution, turns red litmus paper blue C

Has a temperature of -26.3oC NC

Has a mass of 2 g NC

Has a boiling point of -33.5oC C

ELEMENTS AND COMPOUNDS:

• Elements are substances in their pure state such as that found on the periodic table of elements

• Compounds are constituted of two or more elements which have one to three bondswith one another

EX: Copper (or Cu), Iron (or Fe) and Neon (Ne) are elements whereas Salt (NaCl), Ammonia

(NHO3) and Carbon Dioxide (CO2)

MIXTURES (HETEROGENOUS AND HOMOGENOUS):

• Homogeneous mixtures are substance which are equally distributed within another one

• Heterogeneous mixtures are unevenly distributed within another one

EX: Oil and Water is Heterogeneous while A Conductive solution is Homogeneous (Read:

PHYSICAL AND CHEMICAL

CHANGES:

• There are two type of

changes: physical and chemical

changes

• Chemical changes are

permanent.

• Physical changes can be

reversed.




Electrolytes)

PHILOSOPHERS AND SCIENTISTS:

• Aristotle maintained that matter does not contain atoms and that anything can beinfinity divided (Continuous Theory)

• Democritus maintained that matter is made of atoms (Discontinuous Theory) and allthings are made of the same atoms in a different arrangement (the latter beingincorrect)

• Dalton believed in four main rules:1) All mater is composed of tiny indivisible atoms2) All atoms of the same element are the same3) Atoms of different elements are different4) During a chemical reaction, atoms combine and form bonds to create new

atoms

• J.J Thompson maintained three main beliefs:1) Protons are positively charged2) Electrons are negatively charged3) Atoms are neutrally charged because they have the same amount of protons as

they do electrons

• Created the plum pudding model (which is incorrect)

• Rutherford held the belief that:1) The atom is made mostly of space2) The Nucleus is mostly positive3) The nucleus is very dense4) The number of protons and neutrons vary from element to element

• Created the Rutherford model which involved electrons revolving around thenucleus in no particular order

• Niels Bohr added to Rutherford's model by introducing electron orbits and shells

ELECTROSTATICS: Ex:

• All matter is neutral

• Some attract a stronger negative charge thanothers (Silk, Wool,

Cotton, Rubber)

PROTONS, NEUTRONS AND ELECTRONS:Protons1uPositively ChargedInside the Nucleus

Neutrons1uNegatively ChargedInside the Nucleus

Electrons0u (1/1837 u)Negatively ChargedOutside the Nucleus

More Negative

====

Likely to

Receive

More Positive

====

Likely to Give

Away

Rubber

Ebonite

Polyethylene

Cotton

Silk

Wool

GlassAcetate




BOHR-RUTHERFORD DIAGRAMS:

• Energy shells only can hold a certain amount of electrons. Their capacities are asfollows:

• Level 1 = 2

• Level 2 = 8

• Level 3 = 8

• Level 4 = 18

• Level 5 = 32

• Level 6 = 50EX:

CATHODE RAY TUBE:

• Cathode ray tube is made up of a vacuum tube.

• Inside said tube are two electrodes, an anode (+) and a cathode (-)• Energy flows from cathode to anode

• Heater heats up so much it releases electrons

• Electrons bump into argon gas in vacuum and create a greenish ray

• Deflection plates make sure it flows in a beam

• An electron beam is made of electron particles (negative charge)

Particle Calculations

Protons ( p+ ) = ATOMIC NUMBER

Electrons ( e- ) = ATOMIC NUMBERNeutron ( n0 ) = ATOMIC MASS-ATOMIC NUMBER

p+ 3

n0 7

2e- 1e-




RADIOACTIVITY:• Everything Dies ( After you get over the sadness, note that so do elements.)

• Unstable atoms undergo decay• Decay means particles from the atom will fly off into it's surroundings

Name Symbol Charge Penetrating Range

Alpha Particles α + Less

Beta Particles β - More

Gamma Particles γ o Most

COPPER OXIDE LAB:

• When you burn something, you often introduce oxygento it

• When you burn copper you introduce O2 (Oxygen) to it

EX:Cu + O2 = 2 CuO2

PERCENT YIELD:

• Percent yield is equal to:

FINAL MASS------------------------------THEORETICAL YIELD

• Final Mass is given or calculated by subtracting crucible or weighing paper mass

• Theoretical yield is equal to:

•

INITIAL MASS---------------------------- X ATOMIC MASS OF COMPOUND

ATOMIC MASS

NAMES OF THE ELEMENTS (1-36):1 Hydrogen H2 Helium He3 Lithium Li4 Beryllium Be5 Boron B

6 Carbon C7 Nitrogen N8 Oxygen O9 Fluorine F10 Neon Ne




11 Sodium Na12 MagnesiumMg13 Aluminum Al

14 Silicon Si15 PhosphorusP16 Sulfur S17 Chlorine Cl18 Argon Ar 19 Potassium K20 Calcium Ca21 Scandium Sc22 Titanium Ti23 Vanadium V24 Chromium Cr 25 Manganese Mn26 Iron Fe

27 Cobalt Co28 Nickel Ni29 Copper Cu

30 Zinc Zn31 Gallium Ga32 GermaniumGe33 Arsenic As34 Selenium Se35 Bromine Br 36 Krypton Kr 51 Antimony Sb52 Tellurium Te83 Bismuth Bi84 Polonium Po

* Bold elements denote a metalloid

ISOTOPES:

• Two types of Isotopes:

◦ Natural

◦ Artificial

• Natural Isotopes

◦ Found in environment

◦ Most are stable but some are unstable (radioisotopes)

◦ Unstable are radioactive

◦ Some formed during formation of the earth

◦ Some by bombardment of cosmic rays in theatmosphere

◦ EX: Uranium, thorium, radon gas

• Artificial Isotopes

◦ Artificial isotopes are created inside nuclear reactors

◦ Bombardment of atoms with other atomic particles

AVERAGE ATOMIC MASS:• Atomic masses of atoms don't increase regularly

• This is b/c neutrons don't increase regularly

EX:Lithium (Li):

3 Protons , 4 NeutronsTotal: 7 Nucleons So is called Lithium-7 or Li-7




92.58% of all lithium isotopes that exist are Li-77.42% of lithium isotopes are Li-6

Li-6 : 3 Protons, 3 ProtonsTotal: 6 Nucleons So it is called Li-6

• These percentages are called Relative Abundances

• Atomic Mass is not an integer because it is a weighted average

• Atoms of the same element have the same # of protons but neutrons vary

AVERAGE ATOMIC MASS = (MASS NUMBER ISTOPE 1 X % ABUNDANCE 1) +(MASS NUMBER ISTOPE 2 X % ABUNDANCE 2) +(MASS NUMBER ISTOPE 3 X % ABUNDANCE 3)

ETC...

EX: The percent abundance for the isotope of potassium with the least amount of neutron is94%, while the percent abundance of the isotopes with the second-least amount of neutronsis 5%. Calculate the average atomic mass of potassium.

39.10 = ( x-1 x 0.05) +

( x-2 x 0.94) +

( x-3 x 0.01)

CHEMICAL REACTIVITY:

• Reactivity is determined by valence shell

• Families have same valence, ergo the same reactivity

• Group number = valence

•For metals, reactivity increases from right to left in a period and top from bottom in afamily

39.10 = 0.05 x – 0.05 + 0.94 x – 1.88 + 0.01 x

39.10 = -1.93 + x

41.03 = x

(39 x 0.94) +

(40 x 0.05) +

(41 x 0.01) = 39.07u




• For non-metals, reactivity increase left to right in a period and bottom to top in a family

• In chemical reactions, atoms tend to become as stable as possible. They try to acquirethe electron configuration of the closest inert gas in the period by either losing or gaining electrons

EX:

Li + F → LiF3 Na + N → Na3NMg + 2 Cl → MgCl2Ca + 2 Br → CaBr 2Ra + At → Ra2At

PERIODIC TRENDS:

• Certain trends can be observed in the periodic table concerning the atomic properties

• Atomic Mass: The mass in mol/g for each element increases from left to right

• Why? From left to right, up to down, the atomic number increases. This means that theprotons increase and protons make up the majority of the mass of the atom.

• Metallic Properties: Metallic properties like conductors of both electricity and heat.This increases right to left

• Why? Metals are on the right side of the table




• Atomic Radius: Atomic radius (the proximity of the electron shells to the nucleus)increases right to left

• Why? The less positive the nucleus is, the further away the electron shell is, the larger

the atomic radius number is. The nucleus becomes more positive the higher the atomicnumber gets (from left to right)

• Ionization Energy: Energy required to remove 1 mol of electrons from materialcomposed in a single atom (measured in kJ/mol) increases from right to left

• Why? Right side (other than inert gases) already want to give away their electrons

•Electronegativity: Ability of an atom to attract electrons to itself. More or less oppositeof Ionization Energy. Measured on the Paulis Scales, a dimensionless scale from 0.7 to4 (like Richter scale).

• Why? Left side already wants to receive electrons

• Characteristic Properties: Density (g/ml), Boiling Point (ºc or K), Melting Point (ºc or K) etc are all greater in the middle of the table.




METALS, NON-METALS AND METALLOIDS:

• Metals are characteristically electrically and thermally conductive, usually solids atroom temperature, are generally malleable, ductile and lustrous and are found typicallyfrom the 1st to 13th family

• Metalloids have some of the same characteristic properties as metals and someproperties from the non-metals. They are found along the step-line which is locatedbetween the metals and the nonmetals

• Non-Metals are characteristically not lustrous, usually gases at room temperature, notmalleable, ductile or good conductors of electricity and heat. They are foundincreasingly from the 14th to 18th family.

FOUR FAMILIES:• Alkali Metals (IA), when in presence of water create a base and hydrogen gas

EX:2 Li(g) + H2O(l) → 2 LiOH(l) + H2(g)

• Alkaline Earth Metals (IIA), much like Alkali metals, create a base and hydrogen gaswhen in presence of water EX:

Ca + 2 H2O → H2(g) + Ca(OH2)(g)

• Halogens (VIIA), halogens have a high electronegativity and often have colorsattributed to them

• Inert Gases (VIIIA), Inert gases (a.k.a Noble Gases) have a full valence shell and tendnot to bond with other elements. These are, as the family name suggests, gases atroom temperature and are normally colorless unless electrically charged.




MOLECULES:

• Molecules are two or more ionicaly or covalently bonded atoms

• Each atom has a valence (not valence electron)• A valence is the number of bonds that an atom of an element can form

• The octet rule states that an atom with eight electrons in it's outer energy level ischemically stable and unstable

Rules of Valence

1. The valence of an element in family 1, 2, or 3 is the same as the family or groupnumber

2. The valence of an element in family 4, 5, 6 or 7 is equal to 8 minus the family

number (Inert gases do not have a valence value)

EX:Since H can form 1 bond (valence 1) and O can form 2 bonds (valence 2) then O cancombine 2 H atoms to form water

Bonds

• There are two types of chemical bonds (for our purposes):

◦ ionic (exchange electrons)

◦ covalent (sharing electrons)

◦ James (license to kill electrons)

Ionic Bonds

• Atoms that gain or lose electrons take on an electric charge and are called ions

• Bonds formed between ions are called ionic

• Ionic bonds usually only occur between metals and non-metals

11p+ 11p+

11e- 10e-

-------- --------

0 1+

Na0 Na+1

17p+ 17p+

17e- 18e-

-------- --------

0 1-

Cl0 Cl-1




Covalent Bonds

• Atoms that share pairs of electrons are said to form a covalent bond

•

Covalent bond usually only occur between two identical non-metals and two metals

The Cross-Over Rule

1. Write the symbols of the two elements placing the metal first

Mg Br

2. Write the valence of each element as a superscript

Mg2 Br 1

3. Cross over the valencesMg2 Br 1

4. Divide the valences by the G.C.F (if necessary, in this case, it isn't)

Mg1 Br 25. Drop any subscript that is 1

MgBr 2

BALANCING EQUATIONS:

• The most important concept to understand when balancing equations is tat the mass of the reactants is always equal to the mass of the products (Lavoisier's Law of Conservation of Mass)

EX:CH4 + 2 O2 → CO2 + 2 H2O

Reactants Products




Steps for balancing an equation

1. Pick the most complex reactant or product2. Balance the elements contained in that substance on the other side of the equation3. Continue until all substances are balanced4. If there are any fractional coefficients, they must be eliminated by multiplaying every termby a constant

MOLE:

602,000,000,000,000,000,000,000 atoms in a mole (6.02 x 1023)

•The mole is the amount of substance that contains 6.02 x 10

23

particles of thatsubstance

• It can abbreviated as mol

• The number of moles of a given substance can be calculated with the formula

MASS OF SUBSTANCE (g) mn= ----------------------------------------- = --------

MOLAR MASS (g/mol) M

EX:12g of Carbon is 1 mol or Carbon44g of Carbon Dioxide is 1 mol of Carbon Dioxide4g of Helium is 1 mol of Helium40g of Argon is 1 mol of Argon18g of water is 1 mol of water 40g of Calcium is 1 mol of Calcium

STOICHIOMETRY:

• Are you stoic'd for stoichiometry?

• Stoichiometry is a method from which the quantities of substances required or produced from a given equation are defined.

EX:

How many grams of Aluminum Bromide will you need to create the following reaction if youhave 618.81 grams of Potassium Sulphate.

2 AlBr 3 + 3 K2(SO4) → 6 KBr + Al2(SO4)




1 mol K2(SO4) 2 mol AlBr2 266.68 g AlBr2

618.81gK2(SO4) X ------------ X --------------- X ---------------- = 532.33 g

206.67gK2(SO4) 3 mol K2(SO4) 1 mol AlBr2

STRUCTURES OF MATTER:

• Three ways exist to illustrate the structure of matter:

◦ Lewis Dot

◦ Structural Formulas

◦ Dimensional Models

Lewis Dot

• Representation of the valence electrons by placing dots around the elements symbol

• Each family has a different configurationEX:

Structural Formulas

• In a structural formula, we can see the number and nature of the atoms, as well astheir relative position within a molecule

• In a structural formula, the number of lines also represents the number of bondsformed between two atoms

• One line represents the sharing of one pair of electrons, two lines represents twobonds

EX:




Dimensional Formulas

• Matter can be represented in three-dimensional models

•

All bonding rules governing structural formulas apply to dimensional models• All single bonds are shown straight

• All double bonds and triple bonds are curved

• Bonds within a polyatomic molecule are shown slanted

• Balls shown in size relative to their nucleus

NOMENCLATURE:

• There are 3 rules for naming Binary Compounds. This depends on whether thecompounds are

◦ Metal + Non-Metal

◦ Transition Metal + Non-Metal

◦ Non-Metal + Non-Metal

Metal + Non-Metal

• Name of metal + name of non-metal with -ide suffix

EX: NaCl = sodium chloride

CaO = calcium oxideMgF2 = magnesium floride

Transition Metal + Non-Metal

• Name of Metal (with bond number in roman numerals) + name of non-metal with -idesuffix

EX:CuCl2 = copper (II) chlorideAgBr = silver (I) bromideFe2O3 = iron (III) oxide




Non-Metal + Non Metal

• non-metal name with numeric prefix + non-metal name with numeric prefix

Numerical Prefixes:

1. Mono2. Di3. Tri4. Tetra5. Penta6. Plexa

Exception #1 H+ Ion + Halogen

• Hydro + non-metal with -ic suffix + acidEX:

HCl = hydrochloric acidHF = hydrofloric acid

Exception #2 Polyatomic Compounds

• Metal + Radical IonEX:

LiOH = lithium hydroxideMgSO4 = magnesium sulphateCaCO3 = calcium carbonate

Exception #3 Special Cases

• Some compounds were named so long ago that the rules do not apply to them:

EX:H2O water H2O2 peroxideCH4 ammonia

EX:

CO = carbon monoxide

N2O3 = dinitrogen trioxide

PCl3 = phosphorus trichloride

H2O = dihydrogen monoxide (water)

Radicals to know:

- OH-1 hydroxide

- NO-1 nitrate

-SO4-2 sulphate

-PO4-3 phosphate

-CO3-2 carbonate

-NH4+1 ammonium




MAGNETISM:

• Forces in the Universe

◦ Gravity◦ Weak Nuclear Forces

◦ Strong Nuclear Forces

◦ Magnetism (electromagnetism)

• 3 Categories of substances

◦ Magnetic

◦ Ferro-magnetic

◦ Non-magnetic

• Ferro-Magnetic Substances

◦ Any material which can become

magnetic temporarily as long asthey remain in the presence of amagnet

• Ferro-Magnetic Material

◦ Iron

◦ Cobalt

◦ Nickel

• Magnetic Substances

◦ Any material which acts like a

magnet (can be attracted andrepelled by another magnet)

◦ Examples: lodestones, bar magnets

• Non-Magnetic

◦ Any material which is not attractedor repelled by a magnet. A magnetwill not affect it.

• Every magnet has two poles:

◦ North and South

• Like poles repel, unlike poles attract

• As the distance between polesincrease, the magnetic forces decrease.

• All magnets have a magnetic field

◦ Space around a magnet wheremagnetic forces are felt

◦ Lines of forces show you the shape,

direction and strength

ELECTROMAGNETISM:

• A magnetic field created by the motion of electric charges(electrons)

• In other words, not only magnets can produce a magnetic field,current-bearing objects can also

Straight Line Conductors

• Wires which have a current flowing through them, also havea magnetic field




Solenoid

• Coiled wire which have a current flowing though them alsohave a magnetic field of a bar magnet

•

Fingers wrap around the coil in the direction of the currentflow and your thumb points in the direction of the magneticfield lines

CONDUCTORS/INSULATORS:

Conductors

• Conductors are substances which easily allow electricity to flow through them

Insulators

• Insulators are substances which do not allow electricity to flow through them easily

Conductance

• Conductance is a number which tells you how well electricity flows through a




substance

• Conductors have a high conductance number (no duh)

• Unit of Conductance is Siemens (pronounced: see-mens-ha-ha-u-see-ree-us-that-es-

pre-tee-fuh-nee) and the symbol is G• Conductance of wire depends on:

◦ Type of material used

◦ Length of the wire

◦ Diameter of the wire (thickness of cross-sectional area)

◦ Temperature of the wire

Property Change Result

Temperature Increase Decrease

Length Increase Decrease

Diameter Increase Decrease

THEORY ON I/V/R:

Current Intensity

• Current intensity measures the amount of electrons which flows through an electriccircuit in one second. It is often called “current”

• The symbol for current intensity is I

• The unit of current intensity is the ampere (A)

Potential Difference

• Potential difference causes electrons to flow through a circuit

• Potential difference is provided by either a battery or a power supplyResistance

• Conductance is how easily current flow though an object

• Resistance is how difficult it is for current to flow through an object

• The symbol for resistance is R

•

The unit of resistance is Ohms 1Resistance is the reciprocal of conductance or R = -----

G

RESISTORS:• Some resistors have a ceramic coating with color coded bands to indicate the

resistance




OHM'S LAW:• Since voltage and current increases proportionally, there must be a constant to

regulate the increase such that:

V=I/R

EX:

9v

A

10Ω

I=?

9 = I x 10

9/10 = I = 0.9A




Req OF SERIES/PARALLEL/COMBO:

Req Is the equivalent resistance of the circuit.

When the circuit is in series, you simply add the

resistance of all the resistance to get the Req

EX:

If R1 is 10Ω, R2 is 5Ω and R3 is 25Ω, what is

the Req of the circuit on the left?

10Ω+5Ω+25Ω = 30Ω

The Req of a parallel circuit is calculated as followed:

1 1 1

---- = ---- + ---- ....

Req R1 R2

EX:

If R1 is 5Ω, R2 is 10Ω and R3 is 30Ω, what is the Req

of the circuit on the left?

1 1 1 1----- ̈ + ----- + ------ = 0.34 = -----

5Ω 10Ω 30Ω Req1

Req= ----- = 3Ω0.3333

Solving Series-parallel (combination or combo)

circuits involves multiple steps.

EX:If R1 is 20Ω, R2 is 10Ω and R3 is 30Ω, what is the

Req of the circuit on the left?

1 1 1 1

------ = ----- + ------ = 0.133 R2,3 = ----- = 7.5 Ω

R2,3 10Ω 30Ω 0.1333

Req = 7.5 Ω + 20 Ω = 27.5 Ω




KIRCHHOFF SERIES/PARALLEL:

Parallel Series

Current It = I1 + I2 + I3 .... It = I1=I2 =I3 ....

Voltage Vt = V1=V2 =V3 .... Vt = V1 + V2 + V3 ....

POWER EQUATIONS:

• E = Pt

• A = c/s

• I = Q/t

• V = J/c

• V = IR• R = V/I

• R = V/I = (J/c) / (c/s) = (J/c) x (s/c) =(Js/c2)

• R = Js/c2

• P = V2/R

•P = I

2

R• P=VI

• w = J/s

READ A HYDROMETER:

• Each “clock” on the hydrometer represents a digit in a four digitnumber which, when multiplied byten, will show the kW consumed

HEAT:

• Objects which change temperature either gain or lose heat temperature

• Heat energy is given the symbol “Q”

• Heat energy (Q) is determined using the following formula:

Q = mcΔT




• Where

◦ m is mass of the material (g)

◦c is the specific heat capacity of the material (J/gºc)

◦ ΔT is the change in temperature (ºc)

EX: A student heated a certain amount of water (heat capacity of 4.19 J/gºc) in a

calorimeter fitted with a resistor and made the following observations during the experiment.How much heat energy is being made.

Mass :200g Inital. Temp. : 20ºc Final Temp. : 45ºc

Dur. of Experiment : 15m

HEAT -> ELECTICAL ENERGY:

• Heat is energy

• Sometimes, all of the heat generated becomes energy

• When this is true, E = Q

• Other times, only a certain percent of the heat is converted to energy

• When this is true, the following formula is used to determine the % efficiencyQ

◦

% Efficiency = -------- X 100E

CONCENTRATION/SOLUTIONS/DILUTIONS:

• Concentrations can be expressed in three ways:

◦ Mass percent (%)

◦ Concentration in grams per liter (g/L)

◦ Concentration in moles per liter (mol/L)

Solutions and Dilutions

• Solutions can be expressed with the following expression

C1 X V1 = C2 X V2

200g x 4.19J/gºc x 25ºc = 20950 J




ACIDS/BASES/SALTS:

• Acids contain at least one hydrogen atom that can be removed when the acid

dissolved in water, it therefore can donate H+ ion• Bases any substance that form hydroxide ions, OH-, in a water solution is a base. In

addition, a base is any substance that accepts H+ from acids. Most bases have ahydroxide ion.

• Salts neither start with H, nor end with OH: they start with the first part of the formulaof a base and end with the last part of the formula of an acid (because they are formedby the neutralization of an acid with a base)

ACID + BASE → WATER + SALT

H x + yOH →H2O + yx

INDICATORS:

• An indicator is an organic compound that changes color in an acid or a base

• Universal Indicators turn a different color at each pH level

• Most other indicators have one turning point and a total of three different colors

• A turning point is a usually small range in which the indicator changes color

• Both before and after the turning point, indicators usually have different colors

• However, some indicators only have two colors, having the same color for before andafter the turning point

pH:• Stands for “power of hydrogen”

• Scale of acidity or bascicity from 0 to 14

• Measure of the concentration of hydrogen ions within a solution

• Acids have a greater number of H+ ions than OH-

• Neutral (distilled water) contain an equal number of H+ and OH- ions

• Bases contains less H+ ions than OH- ions

• The higher the pH, the more basic it is

• The lower the pH, the more acidic it is

Concentration Formulas and Equations

• The [H+] concentration is equal to ten to the power of the negative pH of the substance

• [H+] = 10-pH

• The pH of a substance is equal to the negative log of the [H+] concentration

• pH = -log([H+])

• The sum of the [H+] concentration plus the [OH-] concentration is equal to ten to thepower of negative fourteen




• [H+][OH-]=10-14

• [H+]=(10-14 / [OH-] )

• [OH-]=( 10-14 / [H+] )

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