Chemistry Midterm

matter

Anything that has mass and takes up space

weight

effect of gravity on mass

inertia

resistance to change in motion

substance

sample of matter

mixture

more than one substance

Mixtures can be separated by

physical means

element

made of more than one atom

alotrope

specific form of an element

heterogeneous

mixture that is in more than one phase

homogeneous

mixture all in one phase

phase

area of space with same characteristics throughout

chemical means

change the identity of the substance

physical means

methods that do not change the identity of the substances involved

isotrope

atoms with a different mass

Compound

made of more than one element and set ratios by number of atoms or mass

anion

A negatively charged ion

cation

A positively charged ion

ions

charged atoms or molecules

ionic bond

when oppositely charged ions attract each other at optimal distance

ionic bonds form

crystal lattice

molecules

atmos held together by a shared electron

covalent bond

a pair of shared electrons

physical properties

used to define substances; observed without changing the identity of a substance

chemical properties

observed by changing the identity of the substance; chemical reaction

evidence of chemical change

color change

evidence of chemical change

change in internal energy

evidence of chemical change

phase change (bubbling of gas) (precipitation of a solid)

evidence of chemical change

production or absorbtion of light

evidence of chemical change

production or absorbtion of electric energy

chemical reaction to define a substance

a chemical property

mass of reactants

equals mass of products

physical property

hardness

physical property

luster

color

physical property; part of the electromagnetic spectrum that are either absorbed or reflected by the substance

electromagnetic spectrum

types of light

solid to liquid

melting point

liquid to gas

boiling point; vaporization

solid to gas

sublimation

liquid to solid

freezing

gas to liquid/solid

condensation

boiling

at a set temperature and pressure all throughout the liquid

Evaporation

any temperature at the surface of a liquid

\`volatility

ease of evaporation

Britleness

shatters when struck

Maleability

gets deformed when struck

Ductility

ability to be drawn into a wire

physical property

magnetism

paramagnetic

substance that is attracted to a magnet

diamagnetic

substance that is repelled by a magnet

mass

amount of matter

volume

amount of space matter takes up

density

mass/volume

extensive properties

dependent on the amount of substance

intensive properties

independent of the amount of substance

Viscosity

how slow a liquid flows

Temperature

average kinetic energy of a system

heat

total kinetic energy of a system

kinetic energy

energy of motion

Velocity

Speed in a given direction

plasma

chemical

purification of substances

separation of mixtures

Distillation

use differences in boiling point to separate in liquid form

vapor

gaseous form of a liquid

filtrations

particles larger than pores in filter are stopped

Recrystallization

separation using variations in solubility characteristics of the compounds involved

saturated solution

maximum amount of solute that will remain dissolved in a solvent at a set tempeture

super saturated solution

when concentration of solute is greater than concentration of a saturated solution

Chromotography

utilizes differences in substances adherence to a stationary phase and their solubility in a mobile phase to separate the mixture

adherence

substances ability to stick to another

coherence

substance's ability to stick to itself

mobile phase

gas; liquid

stationary phase

solid

multiply scientific notation

multiply numbers and add exponents

divide scientific notation

divide numbers and subtract exponents

add scientific notation

must have same exponent, add numbers

subtract scientific notation

must have same exponent, subtract numbers

non-zero digits

significant

all digits between significant digits

significant

atlantic rule

if decimal point is absent, approach number from Atlantic side, 1st zeros are placeholders and not significant

pacific rule

if decimal is present, approach number from Pacific side, 1st zeros are placeholders and not significant

addition and subtraction

round the answer to the least number of places to the decimal point of any number in the problem

multiplication and division

number with least amount of significant figures sets the significance

density of water

1 g/mL

n \> 5 \=

round up

n < 5 \=

round down

n \= 5

round even

round even (odd)

odd next to 5 number goes up

round even (even)

even next to 5 stays and 5 drops

density \=

mass/volume

mass \=

volume x density

volume \=

mass/density

Democrates

first atomic theory, all matter is made of tiny indivisible particles called atoms

Fes

electrostatic force between two charges

unlike charges attract

laws of electricity

all matter is made of sub microscopic particles indivisible particles called atoms (not Democrates)

atomic theory 1

amu is equal to

mass of one carbon 12 atom / 12

atoms of an element are all same and have same properties like color and mass

atomic theory 2

like charges repel

laws of electricity

Law of Multiple Proportions

if you have one element that reacts with a set amount of another element in more than one way to make different products the ratios of the mass of the 1st element in whole number ratios

JJ Thomson

cathode ray tube