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polyatomic ions

ions that are made of more than one atom

State symbols

solid (s), liquid (l), gas (g), and aqueous (aq)

mole

the SI base unit used to measure the amount of a substance

one mole is 6.02×10²³ elementary particles; atoms, ions, particles, molecules

significant figures

All the digits that can be known precisely in a measurement, plus a last estimated digit

Ideal Gas Law

PV=nRT

gas pressure

results from the force exerted by a gas per unit surface area of an object

Real Gases vs. Ideal Gases

1) real gases deviate from ideal behavior at high pressures.

2) real gases deviate from ideal behavior at low temperatures

3) at high temperatures and low pressure real gasses will behave as ideal

4) at high P/low T, the larger the size of the molecules results in a greater deviation from ideal behavior

Combined Gas Law Equation

P1 V1 / n1 T1 = P2 V2 / n2 T2

Mixture

A combination of two or more substances that are not chemically combined

Pure substance

A sample of matter, either a single element or a single compound, that has definite chemical and physical properties

Elements

A molecule composed of one kind of atom; cannot be broken into simpler units by chemical reactions.

Compounds

two or more elements chemically combined

heterogeneous mixture

A mixture that is not uniform in composition; components are not evenly distributed throughout the mixture

homogeneous mixture

A mixture in which substances are evenly distributed throughout the mixture

Atoms

smallest unit of matter, with a nucleus consisting of protons and neutrons and electrons orbiting the nucleus

Molecules

Groups of two or more atoms held together by chemical bonds

Ions

Atom or molecule with a net electric charge due to loss or gain of one or more electron

Avogardo's constant

6.02 x 10^23 particles

Significant Figure Rules

1. non-zeros are always significant; 2. zeros between two other sig figs are significant; 3. all final zeros after the decimal point are significant; 4. zeros used solely for spacing the decimal point are not significant unless a decimal point is present

Liquid vs aqueous

liquid is the melted physical state of a substance (as apposed to solid or gas)

aqueous means dissolved in water

Changes in states of matter

Condensation, Evaporation, Sublimation, Melting, Freezing

states of matter

solid, liquid, gas, plasma

exothermic reaction

a chemical reaction in which heat is released to the surroundings

endothermic reaction

A reaction that absorbs energy

Endothermic vs. Exothermic

Endo: Heat absorbed H>0

Exo: Heat released H

Temperature

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

Kelvin (K) scale

The temperature scale that assigns 0 K to the coldest temperature possible, absolute zero (-273 C), the temperature at which molecular motion stops. The size of the kelvin is identical to that of the Celsius degree.

Celcius to Kelvin

K=C+273

directly proportional relationship

as one amount increases, another amount increases at the same rate. (when x doubles, y doubles)

Inversely proportional relationship

a change in one quantity causes a change by the same factor, in the opposite direction, of another quantity. (when x doubles, y halves)

Assumptions of Ideal Gases

1. ) the particles in a gas are in constant, random motion

2. the combined volume of the particles is negligible

3. the particles exert no forces on one another

4. any collisions between the particles are completely elastic,

5. the average kinetic energy of the particles is proportional to the temperature in kelvins.

pressure

the amount of force exerted per unit area of a surface

Volume

The amount of space an object takes up dm³

kilopascals to pascals

x1000

Convert between the units of meters cubed, (m3) decimeters cubed (dm3), and centimeters cubed (dm3)

1 cubic metre (m^3)= 1000 cubic decimetre (dm3)

1 cubic metre(m^3)= 1,000,000 cubic centimetre (dm3)

Mole formula

moles = mass/molar mass

Density

mass/volume

empirical formula

a formula with the lowest whole-number ratio of elements in a compound

Avogadro's Law

V1/n1 = V2/n2

Molar mass of a gas

M= mRT/PV

what are metaloids

elements that act as metals and non metals

when bonding to elements with higher electronegativity - check the diagram

what bonds do poytomic ions have

covalent bonds

what is the molecular mass for a diatomic particle

double it

what type of bonding forms when two polytomic ions bond together

ionic bond

how to calculate percentage error

uncertainty with two measurements

add them up together

what does it mean when they ask for amount of atoms in a questions

check if they give a molar mass, then see if the compound originally matches it

• if not double the the compound to match

then count how many atoms are in the chemical equation

what does it mean when they say how many molecules

find the number of moles, and then multiply by avogadro’s constant

what is a network covalent bond and which ones to remember

• always solids at room temperature

• strongest bond

• much harder that molecular solids

• higher melting points than molecular solids

Typical example of a giant covalent solid is a diamond, which is made of carbon. Other examples are of silicon (Si) and silicon dioxide (SiO2)

what do different ionisation energy refer to

1st ionization energy

• Mg (s) - Mg ⁺ (g) + e

2nd ionization energy

• Mg ⁺ (g) - Mg ⁺² (g) + e

what does succesive ionization energy meaning

graph or data, showing how ionization energy increases after each energy sub level n = 3 to

n = 2 is a big jump, every electron within the sublevel is a gradual increase

• low ionisation energy for valence electrons