Intro to chem midterms study set

Chemistry

The study of matter, it's properties and changes

Matter

anything that has mass and takes up volume

Natural chemical

Naturally occurring chemical

Synthetic chemical

Synthesized

Organic chemical

Carbon containing

What does not contain chemicals?

NOTHING, everything contains chemicals

What is the scientific method?

To make observations, formulate ideas, and test with experiments

Hypothesis

An educated guess that can be tested

Scientific theory

Describes how or why things happen

Scientific law

Describes what happens

Atom

Basic building block of matter

pure substance

Made of just one elements or compound

Element

Made of one type of atom

Compound

Made of different atoms bonded together

Mixture

Different pure substances mixed together

homogeneous mixture

Evenly mixed together/ pure substance

Ex: salt and water

heterogeneous mixture

Unevenly mixed together

Ex: sand and water

Liquids

Liquids have a indefinite shape, fixed volume, and middle energy

Solids

Solids have a fixed shape and fixed volume with low energy

Gases

Gases have a indefinite shape, indefinite volume with high energy

Solid to liquid

Melting

Liquid to gas

Vaporization

Gas to liquid

Condensation

Liquid to solid

Freezing

Absorbs energy

endothermic

Releases energy

exothermic "ex-exit"

Physical change

Does not change clothes color, shape,

Chemical change

Does change when taste changes and it's

Phase changes are always

Physical changes

all chemical reactions are

chemical changes

mass and temperature are

physical property

radioactivity and reactivity are

chemical property

heating water and melting wax are

physical changes because there phase changes

burning the wick of a candle and souring milk are

chemical changes because the molecules of the candle and milk are both changing.

come back to sig figs

metric system

a system of measurements based on power of 10

length

measurement of distance

metric base unit for length

Meter (m)

kilometer

Km is greater than meter
1km=1000m

centimeter (cm)

centimeter is less than meter
100cm=1m

millimeter(mm)

millimeter is less than a meter
1000mm=1m

conversion

the unit we cancel goes on the bottom (DEM) and the unit we cancel goes on top (NUM)

converting

units in the denominator are divided, and units in the numerator get multiplied.

mass

measurement for amount of matter

metric base unit for mass

Gram (g)

Kilogram (Kg)

1Kg = 1000g

centigram (Cg)

100cg = 1g

milligram (Mg)

1000mg = 1g

volume

measurement of amount of space

metric base unit for volume

Liter (L)

Kiloliter (KL)

1KL = 1000L

centiliter (cL)

100cL = 1L

milliliter (mL)

1000mL = 1L

Temperature

Measurement of hotness/ coldness

high temperature

feels warm = more energy

low temperature

feels cold = less energy

metric base unit for temperature

°C

°C to °F

C x (9/5) + 32 = °F

°F to °C

(5/9) x (F-32) = °C

Accuracy

How close a measurement is to the true match.

Percision

How close repeated measurements are to each other.

digital balance

measures mass in grams (g)

123.45

1=hundreds place
2= tens places
3= one's place
4=tenths place
5= hundredths place

beaker

measures volume in mL and the estimated digit is the one place. The smallest marking is in 10 mL

100 mL graduated cylinder

measure in mL and the estimated digit is in the tens place. the smallest marking is in 1mL

10 mL graduated cylinder

measures in mL and the estimated digit is in hundredths place. the smallest marking is 0.1 mL. This cylinder is the most percise.

Meniscus

curve formed by water in narrow glass wear. The bottom is were the most accurate number is.

thermometer

measure in temperature °C. smallest marking is 1 °C. and the estimated digit is in the tenths places

coloums are

groups (vertical)

rows are

periods (horizontal)

group 1 is

alkali metals

group 2 is

alkaline earth metals

group 7 is

hologens

group 8 is

the noble gases

the staircase is

called metalloids. What is on the left of the staircase are metals. what is on the right are nonmetals.

symbol labels

the atomic number is the number of protons and electrons

protons are

positively charged

electrons are

negatively charged

nuetrons are

neutrally charged

in a neutral atom

the number of protons is equal to the number of electrons.

in a positive atom

the number of protons is greater than the number of electrons

in a negative atom

the number of electrons is greater than the number of protons.

atomic number

defines the element and how much protons it has and electrons only if its neutral.

nuclear symbol

is the mass symbol and is located in the upper left corner.

to find the number of electrons, protons and neutrons in a neutral atom with a mass number

protons are the same as the atomic mass and in a neutral atom, protons and electrons are equal.
protons - mass numbers = nuetrons.

isotopes

Atoms of the same element that have different numbers of neutrons

isotopes have

the same number of protons, but a different mass number and a number of neutrons.

mass number formula

#P + #N

molar mass

weighted average of the mass # of all the isotopes of the element

molar mass and mass number

molar is a decimal and mass number is always a whole number.

negative charge

when a charge is negative, add it to the number of protons to find the number of electrons.
ex: Fe -1 -1 + 9p = 10e

positive charge

if a charge is positive, subtract it from the number of protons to get the number of electrons.
Na + +1 - 11p = 10e

cation

positive ion, loses electrons, #p is greater than the #e

anions

negative ions, gains electrons, #E is greater than #p

Denisty

mass/volume

density of a liquid

units g/ml
subtract the mass of an empty cylinder - the mass of the filled cylinder = / by the volume of the liquid in the cylinder.

density of a solid

units g/cm3
multiply the length x width and height of the solid and then divide by the mass of the block.

measurement of a irregular shaped solid

subtract the amount of water in the cylinder - the mL the water rises to and then divide against the mass of the solid.

if 2 objects hae the same volume

the object with the greater density will have a greater mass because more atoms are packed closer together.

volume is

space an object takes up