chem imnida

matter

• anything that takes up space and has mass

• composed of atoms and molecules

• exists in various forms and shapes

chemistry

study of matter

solid, liquid, gas and plasma

states of matter

plasma

• ionized gas with free electrons

• occurs at very high temperatures (stars, lightning)

• conducts electricity and is affected by magnetic fields

substance

• any variety of matter w identical properties and composition

• elements or compounds

elements

• cannot be broken down chemically

• one type of atom

• represented by chemical symbols

compounds

• can be broken down into simpler substances chemically

• 2 or more different types of atoms chemically bonded together

• chemical formulas

mixtures

results of the combination of elements and/or compounds

• not chemically combined

• ratios of substances can vary

• can be separated into the original elements and/or compounds

homogeneous mixture

• uniform appearance throughout

• only have ONE phase

• components are evenly distributed and cannot be distinguished

saltwater, fog, air, milk

examples of homogeneous mixtures

solution

• a type of homogeneous mixture

• transparent; particle sizes at the molecule or ion level

• air, soda, vinegar

colloid

• a type of homogeneous mixture

• homogeneous to the naked eye; with particle sizes that consist of clumps of molecules

• not separated by filtration

• fog, milk

suspension

• a type of heterogeneous mixture

• particles are large enough to be visible to the naked eye

• can be separated by filtration

• blood and aerosol sprays

heterogeneous mixture

• mixtures that are made up of more than one phase or of different parts

• can be separated physically

• the components are visibly distinguishable from one another

• salad, pizza, beach sand

melting

solid to liquid

freezing

liquid to solid

vaporization

liquid to gas

condensation

gas to liquid

sublimation

solid to gas

deposition

gas to solid

combustion

• burning a substance in the presence of oxygen

• example of chemical change

oxidation

• example of chemical change

• reaction with oxygen to form oxides

neutralization

• example of chemical change

• reaction between acid and a base to form salt and water

fermentation

• example of chemical change

• conversion of sugars into alcohol & carbon dioxide by yeast

filtration

• separation technique

• separates solids from liquids using a porous barrier

• ex. sand from water

distillation

• separation technique

• separates substances based on differences in boiling points

• ex. purifying water by boiling and condensing

chromatography

• separation technique

• separation based on their movement through a stationary phase

• ex. pigments in ink

centrifugation

• separation technique

• based on their density by spinning at high speeds

• ex. blood components

magnetism

• separation technique

• separates magnetic materials from non magnetic

• ex. removing iron fillings from sand-iron mixture

energy

• ability to do work

• it is conserved, not created or destroyed

potential energy

stored energy

pe = mgh

formula for potential energy

kinetic energy

moving energy

ke = 1/2mv²

formula for kinetic energy

exothermic reaction

when more energy is released than absorbed

endothermic reaction

when more energy is absorbed than released

boyle’s law

• at a constant temperature, there is an inverse relationship between pressure and volume

• P1V1=P2V2

temperature

• average kinetic energy of a sample

• measures motion not heat

celsius

• based upon the freezing points and boiling points of water

• 0 and 100 degrees

kelvin

• based upon the lowest temperature that can be achieved, 0 k or absolute zero

• C + 273

fahrenheit

• freezing point of water is 32 degrees and boiling point is 212 degrees

solute

substance that is dissolving

solvent

• substance that does the dissolving

• usually present in the greatest amount

water

most common solvent in chemistry

aqueous solution

solution with water as the solvent

alloy

homogeneous mixture or solution of metals

1. take different metals

2. melt and mix while molten

3. cool and solidify

4. the two metals evenly spread and uniform

5. alloy

how do u make an alloy

atoms

• building blocks of everything

• smallest unit of an element

• composed of nucleus (protons and neutrons) and electrons orbiting the nucleus

molecule

• combinations of 2 or more atoms which are held together by chemical bonds

• smallest portion of a substance which showcases all the properties of the substance

leucippus and democritus

proposed atomos — the indivisibility of atom

john dalton

• proposed the atomic theory of matter

• he described atom as a solid, hard, and indestructible sphere like a billiard ball

atomic theory of matter

according to the ____, matter is made up of very small, invisible, and indivisible particles called atoms.

joseph john thomson

• proposed plum-pudding model

• discovered electrons

plum-pudding model

according to the ___, atoms could sometimes eject a far smaller negative particle which jj thomson called an electron.

protons

• positive charged particles

• tells u the atomic number of an element

• heavy mass

• found inside the nucleus

neutrons

• neutral particles (no charged)

• heavy mass

• found inside the nucleus

electrons

• negative charged particles

• extremely small and light mass

• found outside the nucleus

ernest rutherford

• discovered the nucleus of the atom using his alpha scattering experiment

• nuclear model; gold foil experiment

james chadwick

• found a neutral particle inside the nucleus (neutron)

niels bohr

• proposed planetary model

  • atomic model similar to the solar system where electrons are found revolving around the nucleus

  • electrons are found in specific energy levels

nucleus

• center of the atom

• contains mass of the atom

• includes protons and neutrons

electron cloud

region that surrounds nucleus

ions

• when an atom loses or gains one or more electrons, it acquires a net electrical charge

• cation and anions

cation

• when an atom loses an electron to another atom

• more protons than electrons = positive charged

anion

• when an atom gains an electron from another atom

• less protons than electrons = negative charged

isotopes

• atoms of the same element with different mass numbers

• same number of electrons and protons, different number of neutrons

• ex. protium (h-1), deuterium (h-2), tritium (h-3)

ionization

process in which an atom loses or gains electrons

number of protons

how to find the atomic number

protons + neutrons

how to calculate for the mass number of an element

mass number - protons

how to calculate for the number of neutrons

atomic number - charge number

how to find electrons

periods

• left to right

• elements in the same period all share the same number of energy shells

• new period row = new shell

groups

• column

• elements in the same group share the same number of electrons in their outermost shell

• similar properties

alkali metals

• group 1

• very reactive

• has 1 valence electron

• form positive charged ions

hydrogen

• H

• atomic number 1

• atomic mass 1

• only non metal in group 1

lithium, sodium, potassium

examples of alkali metals

alkali earth metals

• group 2

• has 2 valence electrons

• forms +2 charged ions

• also reactive but not as reactive as alkali metals

beryllium, magnesium, calcium, strontium, barium, radium

examples of alkaline earth metals

transition metals

• middle part in the periodic table

• some are reactive, soem

• iron

• cobalt

• nickel

• copper

• silver

• gold

• zinc

• mercury

• platinum

examples of transition metals

halogens

• group 7A or 17

• has 7 valence electrons

• form -1 charged ions

• VERY reactive NONMETALS

• fluorine

• chlorine

• bromine

• iodine

examples of halogens

noble gases

• chemically inert

• not reactive

• very stable elements

• their outer shells are full

helium, neon, argon, krypton, xenon

examples of noble gases

metals

• give away electrons

• electropositive

• left side of the periodic table

• conductor of heat and electricity

Francium (Fr)

most electropositive element (gives away electrons easily)

non metals

• gains electrons

• electronegative

• upper right side of the periodic table

• insulator of heat and electricity

Fluorine (F)

most electronegative element (strongly attract and gain electrons)

metalloids

• semi metal

• not pure insulators and conductors

• silicon and germanium are the most common

its electrical conductivity also increases

what happens to the electrical conductivity when you increase the temperature of a metalloid?

metals can become superconductors if the temperature is super low or at absolute zero

what happens to the electrical conductivity when you decrease the temperature of a metal?

ionic bonding

• metal + non metal

• transfer of electrons

• has a high melting point

• conducts electricity when molten/dissolved

covalent bonding

• non metal + non metal

• share electrons

• common in gases, liquids, solids

• does not conduct heat and electricity

metallic bonding

• metal + metal

• free-moving electrons

• great conductor of electricity

metallic bonding creates a sea of delocalized valence electrons that are free to move and carry the electric charge throughout the structure.

why are metallic compounds great conductors of electricity?

synthesis reaction (combination)

• multiple reactants combining to form one product

• type of chemical reaction

• H2 + O2 = H2O

decomposition reaction

• breakdown of a compound into simpler elements

• type of chemical reaction

• Mg3N2 = 3Mg + N2

combustion

• typically involves carbon, hydrogen, and oxygen

• type of chemical reaction

• something burns..

single replacement

• one element in a compound is replaced by another element

• type of chemical reaction

• AB + C = A + BC

double replacement

• 2 reactants exchange one atom with each other

• type of chemical reaction

• AB + CD = AC + BD