DAT Chemistry - procedures

Compound

molecule containing 2 different elements

Molecule

group of two or more atoms biund together

monoatomic atoms

elements that stably exist in nature as uncharged single atoms

Diatomic atoms

elements that do not exist stably in nature as uncharged single atoms

7 diatomic atoms

allotropes

elements that can exist in nature with various elemental formulas

O2,O3

S6, S8, S12

Ionic compounds

metal + nonmetal (ionic bonds)

Nacl, cucl2

NH4Cl is exception

molecular compounds

Two or more nonmetals

Contain covalent bonds

metals

How to name ionic compounds

1. write metal

2. write metal’s oxidation state as roman numeral in parenthesis

3. Name nonmetal using “ide”

Exceptions to ionic compund naming rule

columns 1 or 2 and Al Zn Cd and Ag

naming molecular compounds

A_XB_Y

1. Give appropriate prefix to first element (unless x=1)

2. Name the first element bu using regular name

3. give appropriate numerical prefic to second element

4. end with ide

Binary acid

acid that has H and one other element

Naming Binary acids

hydro + insert name of element 2

At the end, add “ic acid”

Oxyacids

acid that has H, one other element, and a varibale amount of oxygens

H_x - middle atom - O_Z

Naming oxyacids

H_x - middle atom - O_Z

if Z is 0-2, Hypo + element 2 + ous acid

if Z is 3, element 2 + ous acid

if Z is 4, element 2 + ic acid

if Z is 5, per+ element 2 + ic acid

if Z is 0-2

Naming oxyacids

H_x - middle atom - O_Z

Hypo + element 2 + ous acid

if Z is 3

Naming oxyacids

H_x - middle atom - O_Z

element 2 + ous acid

if Z is 4

Naming oxyacids

H_x - middle atom - O_Z

element 2 + ic acid

if Z is 5

Naming oxyacids

H_x - middle atom - O_Z

per+ element 2 + ic acid

precision

how close measurements are to each other

accuracy

how close a meaurement is to reality

spectrophotometer

measures a solution’s concentration via how much light passes through a sample

seperatory funnel

seperate the components of a heterogenous mixture

in polar vs nonpolar layers

condensers

seperate homogenous liquids

water jacket is condenser

Buchner funnels

Used during vacuum filtration, buchner funnels sit on top of the flask and holds filter paper

Centrifuge

seperates compunds in heterogenous mixture based on densities (lowest on bottom)

Beakers

used for stirring, mixing, and heating

not for measuring volumes

Erlenmeyer flask

Used for transfering/ mixing liquids for reactions, not for accurate volume measurements

Often used for titrations

Graduated cylinders

used for transferring liquids or for general measurements

Nearest mL

Burretes

used for transfering precise amounts during titrations

divided into 0.1 mL increments

Recorded to the nearest 0.01

Volumetric flasks

known liquid amounts, make mixtures

volumentric pipets

very accurately meassure liquid volumes (most accurate) but can only measure one specific one

can lead to inefficiencies, ineffective at reading varied volumes/ decimals

Accuracy of chem lab equipment

How to dilute strong acid

very exothermic,

add acid to water, not the other way around

How to heat a test tube

use a test tube holder, not hand

heat test tube with water bath, not open flame

What do lab coats protect from

alpha particles

hazardous materials

some fire resistance

decrease the spread of hazardous materials

What happens if fire breaks out in lab

1. leave immediatley

2. activate fire alarm

3. notify teaching assistant

Glass disposal

glass waste

used paper towels and spill pads disposal

solid waste

leftover acid disposal

acid waste container

uncontaminated water disposal

down the sink

How to weigh solids

Pour solid out of container

tare weighpaper, then measure

dispose of waste

parallax errors

when misreading liquid volume due to looking at it from an icorrect angle

How to use a pH meter

calibrate probe by using a calibrated buffer of pH 4 and 10

Rinse pH probe with DI water in between samples

dab probe dry so you dont throw off measurement

Buret measurement

top to down

graduated cylinder measurement

down to top

Molecular weights

mass of a molecule, add up wieights of each atom

Combustion reactions

C_XH_Y

or

C_XH_YOH

reacts with O₂ , get CO₂ and H₂O

molecular formulas

actual elemental symbols and numbers

empirical formulas

most reduced whole number ratio of a molecule

percent composition

Weight of element/weight of total mass * 100

easy method of balancing equations

count polyatomic ions as their own thing