TEAS CHEMISTRY

protons

a stable subatomic particle in the atomic nuclei with a positive charge equal in magnitude to that of an electron, but of opposite sign

neutrons

a subatomic particle of about the same mass as a proton but without an electrical charge

electrons

a negatively charged subatomic particle that is 1/1836 times smaller than a proton

___ & ___ are equal

protons & electrons

mass of neutrons & protons

1.67 × 10^-24 (1 amu)

mass of electrons

9.109 × 10^-28 (0.000549 amu)

atomic number

how many protons are in an element

atomic mass

how many protons and neutrons are in an element

neutron number

atomic mass — atomic number

isotopes

distinct, nuclear species of the same chemical element; have the same atomic # & position in the periodic table but they differ in the number of neutrons

ion

an atom/group of atoms with a net electrical charge; becomes an ___ if it gains/lose electrons

cation (+)

loses electrons

anion (—)

gains electrons

shell

electrons revolve around the nucleus in a specific circular path

sub-shell

a subdivision of electron shells separated by electron orbitals

K shell

n=1, s sub-shell

L shell

n=2, s+p sub-shell

M shell

n=3, s+p+d sub-shell

N shell

n=4, s+p+d+f sub-shell

chemical bonds

only electrons in the outermost shell participate in ___

orbital

three-dimensional space within an atom where an electron in a given subshell can be found

s sub-shell

1 orbital, holds maximum 2 electrons

p sub-shell

3 orbital, holds maximum 6 electrons

d sub-shell

5 orbitals, holds maximum 10 electrons

f sub-shell

7 orbitals, holds maximum 14 electrons

ionic bonds

complete transfer of valence electrons between atoms; one atom takes it all

covalent bonds

sharing of electrons to form elements pairs between atoms; between nonmetals; C+O+H+N mostly form ___ ___

matter

anything that has weight and occupies space/volume; solids, liquid, gas states

mass

the amount of matter an object contains; measured in grams (g) + kilograms (kg)

volume

the amount of space an object occupies; measured in liters (L) + milliliters (mL)

density (mass/volume)

relationship between the mass and volume of an object; same volume different mass

solid

definite shape: particles anchored/vibrating in position

definite volume

cannot compress: no space between particles packed together tightly

liquid

indefinite shape: particles can move into new locations, packed close together but not fixed, in constant motion + move freely past e/o

definite volume

cannot compress: not much space between particles

gas

indefinite shape: particles can move into new locations, continuous fast movement

indefinite volume: particles are widely sparse & freely flying around

compressible: particles are widely spaced

temperature

measures the average kinetic energy (speed) of particles in a substance

pressure

the physical force applied perpendicularly to a surface per unit area, primarily resulting from gas or fluid particles colliding with that surface

changes in matter

melting

when a solid gains heat and changes into a liquid

freezing

when a liquid loses heat and turns into a solid

condensation

when a gas loses heat and turns into a liquid

evaporation

when a liquid turns into a gas, usually when the liquid is heated

sublimation

when a solid changes directly into a gas without first becoming a liquid

deposition

when a gas changes directly into a solid without first becoming a liquid

chemical reactions

one or more substances, known as reactants, that are transferred into different substances called products

reactants

substances present at the start of a chemical reaction that participate in the reaction

products

substances that are formed as a result of a chemical reaction

reversible reactions

can proceed in both the forward (reactants to products) and reverse (products to reactants) directions.

irreversible reactions

proceed in only one direction, going to completion until one of the reactants is completely consumed

combination/synthesis reactions

two or more substances combine to form a single product

decomposition

a single substance breaks down into two or more simpler substances

displacement

one element in a compound is replaced by another element

double displacement

elements in two different compounds swap places with each other to form two new compounds

combustion

a substance (usually hydrocarbon) reacts with oxygen to produce heat, light, and typically produce CO₂ and H₂O

moles

unit of measurement that is the amount of a pure substance containing the same number of chemical units

avogardro’s number

6.022 × 10²³

temperature, concentration/pressure, surface area, catalyst

factors affecting chemical reactions:

collision theory

for particles to react, they have to collide with each other with sufficient energy (activation energy)

amount of energy particles have=more energy can transfer during collision + frequency of collisions=higher frequency of colliding, higher probability of successful collisions

reaction rate depends on:

particles gain more energy→move faster→collide with more energy→collide more frequently→more likely to exceed activation energy=higher rate of successful collisions

as temperatures increases:

more particles per unit of volume→collide more frequently=higher rate of successful collisions

as concentration (solutions)/pressure (gases) increase:

higher surface area to volume ration→collide more frequently=higher rate of successful collisions

as surface area increase:

catalyst

substances that speed up a reaction without being used up in the reaction themselves

exothermic reactions

releases energy, release heat

endothermic reactions

takes in heat, absorbs heat

chemical equilibrium

when the rate of the forward reaction equals the rate of the reverse reaction in a closed system

static equilibrium

a state in mechanics where an object is completely at rest and remains so because all forces and rotational tendencies (torques) acting upon it are perfectly balanced

dynamic equilibrium

the forward and reverse reactions are occurring at the same time

adhesion

binding/attraction between dissimilar molecules, atoms, surfaces, and substances

cohesion

attraction of molecules for other molecules of the same kind

solute

a substance that can be dissolved into a solution by a solvent and is present in smaller amounts

solvent

a substance with the ability to dissolve other substances to form a solution and is present in larger amounts

solution

a homogeneous mixture of one of more solutes dissolved in a solvent

homogeneous mixture

uniform composition (everything mixed together, dissolved completely)

heterogenous mixture

non-uniform composition (can see individual particles, not dissolved completely)

polar substances

soluble in water, hydrophilic (water-loving)

non-polar substances

insoluble in water, hydrophobic (water-fearing)

concentration

the measure of the amount of solutes that has been dissolved in a given amount of solvent/solution

molarity (moles/liter)

number of moles of solute per one liter of solution

dilution (M₁V₁=M₂V₂)

process of reducing the concentration of a solute in a solution by adding more solvent

osmosis

spontaneous net movement/diffusion of solvent molecules (water) through a selectively permeable membrane from a region of high water potential to a region of low water potential; passive transport; MOVEMENT OF WATER

hypotonic solution

low solute concentration of salt/sugar than the blood, solutes flow into cell=swell and burst

hypertonic solution

higher solute concentration of salt/sugar than the blood, solutes flow out of cell=cell shrinks

isotonic solution

contains the same concentration of water/solutes, no osmotic flow

diffusion

net movement of anything generally from a region of higher concentration to a region of lower concentration driven by a gradient in free energy/chemical potential; passive transport; MOVEMENT OF PARTICLES

facilitated diffusion

passive transport process that allows specific large, polar, or charged molecules (like glucose or ions) to cross cell membranes through special transport proteins

distance, temperature, solvent characteristics, traveling characteristics, barrier characteristics

factors that affect diffusion:

distance

the greater the distance, the slower the diffusion rate

temperature

higher temp causes an increase in diffusion rate

solvent characteristics

increased density can slow molecules down decreasing diffusion

traveling characteristics

the greater the mass the lower the diffusion rate

barrier characteristics

small non-polar cells pass through barriers easily

active transport

molecules move from a lower concentration to a higher concentration using ATP (energy)

pH scale

a measure of how acidic or alkaline a solution is

acid

substances that increase concentration of hydrogen ions (H+), forms aqueous solutions with a pH less than 7

base

substances with decrease concentration of hydrogen ions (OH-), forms solutions with a pH greater than 7

wide range indicator

chemical compound that changes based on pH

universal indicator

color range from deep red in very acidic to blue/purple in very alkaline

red under acidic conditions

blue litmus paper turns:

blue under alkaline conditions

red litmus paper turns:

neutralization reaction

when acids + bases mix together oftentimes forming water & salt