Chemistry Exam Grade 11

Chemistry

The study of matter, its nature, and the changes it can undergo

Matter

Anything that has mass and takes up space

Mass

the amount of matter in an object

Weight

A measure of the force of gravity on an object

Democritus

Greek philosopher that said all matter is made of tiny particles called "atomos" or atoms

Dalton

Created the first practical model of the atom.

Dalton's Atomic Theory

1) all matter is composed of tiny particles called atoms.

2) all atoms of an element are identical

3) atoms of different elements are different from all others

4) atoms of different elements combine in simple ratios to form compounds

5) during a chemical reaction, atoms are neither created nor destroyed but they join together, or they separate from one another, or they are rearranged.

Crooke

DId experiments involving cathode ray tubes. found some properties of electrons

Crookes’ Experiment

1) in a CRT a glow was created regardless of the element used for the cathode

2) a thin cross was inserted in a CRT , a sharp clear and focused shadow was produced. Cathode rays travel in a straight line and cannot penetrate metal

Crooke's Experiments and Conclusions 3-4

3) a paddle wheel was inserted into the CRT. the paddle was free to move on the track. the wheel moved away from the cathode. Cathode rays exert a force therefore they have mass

4) a magnet was brought near a CRT. Cathode Rays were deflected by the magnet. Cathode Rays have a negative charge.

Thomson's Model of the Atom

Showed that the electron had a much lower mass than the lightest atom. He pictured the atom as a sphere with a positive charge spread uniformly through the atom with electrons embedded in them. The "Raisin Bun" model

Rutherford's Discovery

Gold foil experiment, discovered nucleus

Bohr's Model

planetary model of the atom

Isotopes

Atoms of the same element that have different numbers of neutrons

average atomic mass formula

(mass)(%)+(mass)(%)/100

Organization of the Periodic Table

the elements into periods (rows) and groups (columns) by increasing atomic number. elements with similar properties are in the same group

atomic radius

increases down a group, decreases across a period

Trends: ionic size

size generally increases going down a group and decreases going across a period

electron affinity

increases across a period, decreases down a group

Trends: ionization energy

increases across a period, decreases down a group

Trends: reactivity of metals/nonmetals

metals: increases by group, decreases by period

nonmetals: decreases by group, increases by period

Ionic bonding

when two atoms form an ionic compound through the "trading" of electrons. For example Na + Cl -> NaCl this happens because Na has one valence electron and Cl has 7 valence electrons. Na gives away its electron to Cl making both stable

Ionic Valence

The number of electrons lost or gained by an atom to form an ion. It is the charge an ion has.

ionic solids

solids which are composed of ions; they generally have high melting points

Ionic dissociation

the process of separating a solute into individual ions in a solution

Covalent Bonding

a bond that results from the sharing of electron pairs between two atoms. usually takes place between a nonmetal and a nonmetal

molecule

Two or more atoms bonded together

bond energy

the energy required to break a chemical bond

molecular formula

A chemical formula that shows the number and kinds of atoms in a molecule

molecular solids

Solids that are composed of molecules held together by their intermolecular forces. weak bonds

Covalent solids

atoms held together by covalent bonds. High melting points.

molecular dissociation

the process by which a molecule splits into its component atoms

covalent ionization

ONLY ACIDS AND AMMONIA

A chemical process by which the molecules of a compound react with water to produce ions. The solution will conduct electricity.

polar covalent bond

A covalent bond in which electrons are not shared equally

pure covalent bond

neutral atoms held together by equally shared electrons

polyatomic ion

A charged group of covalently bonded atoms

reaction

process of molecular change

reactant

A chemical substance that is present at the start of a chemical reaction

product

A substance produced in a chemical reaction

how to balance equations

you must change the coefficient of each reactant and product so that there are the same number of atoms of each element

Types of Reactions

synthesis, decomposition, single displacement, double displacement, neutralization, complete combustion, incomplete combustion

Types of Reactions: Synthesis

A + B --> AB

two reactants or more react to form a single product

Types of Reactions: Decomposition

AB --> A + B

one reactant forms more than one product

Types of Reactions: Single Displacement

A + CD --> AD + C

one element takes the place of another element in a compound

Types of Reactions: Double Displacement

AB + CD --> AD + CB

the exchange of anions between 2 compounds

Types of Reactions: Neutralization

HNO3 + NaOH --> NaNO3 + H2O

a double displacement reaction in which an acid and a base react to form water and an ionic compound

Interjection: what is a hydrocarbon

a substance consisting of carbon and hydrogen

(CH4, CH3)

Types of Reactions: Combustion

The burning of a hydrocarbon in oxygen

Types of Reactions: Combustion Incomplete vs Complete

Complete: there is an abundance of oxygen, carbon dioxide, and water are produced , no matter the hydrocarbon

Incomplete: when the amount of oxygen gas available is limited, carbon monoxide and water are produced no matter the hydrocarbon

Activity Series

a list of elements in order of decreasing reactivity. elements higher in the reactivity series will replace elements lower in the series during single displacement reactions

Avogadro's number

1 mole is 6.02 x 10^23

How to find the number of particles from number of mol

multiply the number of mol by Avogadro's Number/6.02*10^23

How to find the number of mol from a number of particles

divide the number of particles by Avogadro's Number/6.02*10^23

Molar Mass

the mass of one mole of a substance

How to calculate molar mass

addition of atomic mass on periodic table is the molar mass

how to find number of mol from mass and molar mass

n = m/M

law of definite proportions (law of constant composition)

in a given compound, the elements are always present in the same proportion by mass.

empirical formula

the simplest formula

shows the smallest whole number ratio of atom types in a compound

valuable because it leads to the calculation of molecular formulas

How to find empirical formula

a table with these columns: element, mass(g), molar mass, number of moles, ratio

if you are given a percent composition but no total mass then the total mass becomes 100g

50% Na = 50g Na

the Ratio is found by dividing every number of mole number by the smallest number of moles. the ratio must be a whole number, if the ratio number is 1.5 you can double all the ratios to make it work

molecular formula

shows the number of atoms of each element in a compound

ONLY applies to molecules

used to distinguish between compounds because more than one compound can have the same empirical formula

Solute

A substance that is dissolved in a solution.

Solvent

the substance in which the solute dissolves

Solution

A homogeneous mixture of two or more substances

Precipitate

A solid that forms from a solution during a chemical reaction.

Properties of water

the universal solvent, polar

Rate of dissolving

How fast a solute dissolves in a solvent

Solubility: Gases

decreases as temperature increases, dissolves in liquids better at higher pressures

Solubility: Liquids

increases as temperature increases

Solubility: Solids

increases as temperature increases

Types of Solutions

saturated, unsaturated, supersaturated

Types of Solutions: Saturated

a solution that has dissolved all the solute it can

Types of Solutions: Unsaturated

a solution that could still dissolve more solute

Types of Solutions: Supersaturated

a solution that has more solute dissolved in it than should be possible. this could happen because of a solution at a high temperature having solute dissolved into it until it is saturated then the temperature decreases which decreases the amount of solute that can dissolve.

Dilution

adding more solvent to a solution to make the concentration decrease.

Concentration

how much solute is in a solvent

Concentration, Volume, and Moles equations

C = n/v

C1 V2 = C2 V2

Percent Concentration

m/m%, m/v%, v/v%

mass/mass percent, mass/volume percent, volume/volume percent

parts per m(illion)b(illion)t(rillion)

mass of solute/mass of solvent * 10^6(million) or 10^9(billion) or 10^12(trillion)

intermolecular forces

dipole-dipole, ion-dipole, hydrogen bonds

intermolecular forces: Dipole-Dipole

The attraction between opposite charges on two polar molecules. these are weak attractions

intermolecular forces: Ion-Dipole

the attractive forces between an ion and a polar molecule. The negative end of the dipole attracts cations and the positive end of the dipole attracts anions

intermolecular forces: Hydrogen Bonds

the attraction between hydrogen atoms bonded to N, O, or F atoms on one molecule to a lone pair of electrons of an N, O, or F atom on another molecule. 1/10th as strong as a covalent bond

acid

molecular compounds that ionize into hydrogen ions and anions in water

properties of acids

1 tastes sour

2 pH less than 7

3 corrosive

4 conduct electricity

5 react with metals to produce H2(g)

6 can be an oxyacid or binary acid

base

ionic compounds that dissociate into cations and hydroxide ions in water

properties of bases

1 slippery

2 bitter

3 pH higher than 7

4 corrosive

5 conduct electricity

6 dissolve by ionic dissociation except NH3

7 react with fats and oils to produce soap

8 don't react with metals

Arrhenius theory

acids are characterized by their sour taste, and low Ph. Bases are characterized by their bitter taste, slippery feel, and high pH

pH

the hydrogen ion concentration in a solution

strength vs concentration

Strength is a measure of the degree of dissociation of an acid or base in solution, independent of its concentration.

Concentration refers to the amount of solute per quantity of solution.

neutralization

A reaction between an acid and a base resulting in salt and water as products

salt

ionic compound consisting of a metal cation from a base and an anion from an acid

properties of gases

expansion, fluidity, low density, compressibility, diffusion and effusion

kinetic molecular theory

the theory that all matter is composed of particles (atoms and molecules) moving constantly in random directions

pressure

the amount of force exerted per unit area of a surface

temperature

A measure of the average energy of motion of the particles of a substance.

kinetic energy

the energy an object has due to its motion

how to convert between kPa, mmHg, Torr atm

101.3 kPa = 1 atm = 760 torr = 760 mmHg

STP and SATP

STP is 0 degrees celsius

Standard temperature and pressure

SATP is 25 degrees celsius

standard ambient temperature and pressure

Kelvin Temperature

C + 273 = K

0 kelvin is absolute 0

Boyle's Law

if the temperature and the mass of a gas are kept constant, then the volume of the gas is inversely proportional to the applied pressure.

P1V1 = P2V2