Chemistry Lab Chemistry Lab EquipmentEquipment

BeakersBeakers

Wide mouth gas collecting bottles Wide mouth gas collecting bottles with glass plateswith glass plates

Test tube brushesTest tube brushes

Flint Burner LighterFlint Burner Lighter

Crucible and LidCrucible and Lid

Graduated CylinderGraduated Cylinder

Evaporating DishEvaporating Dish

Medicine droppersMedicine droppers

Erlenmeyer FlaskErlenmeyer Flask

Chemical ForcepsChemical Forceps

Glass FunnelGlass Funnel

Red and Blue Litmus PaperRed and Blue Litmus Paper

Spot PlateSpot Plate

Micro Spatula and Scoop SpatulaMicro Spatula and Scoop Spatula

Plastic SpoonPlastic Spoon

Stirring RodsStirring Rods

Hand Test Tube HolderHand Test Tube Holder

Test Tube Rack and Small Test TubesTest Tube Rack and Small Test Tubes

Standard Test TubesStandard Test Tubes

Watch GlassWatch Glass

Beaker TongsBeaker Tongs

Bunsen BurnerBunsen Burner

Crucible TongsCrucible Tongs

Lab Apron (Folded)Lab Apron (Folded)

Ring Stand and ClampsRing Stand and Clamps

Plastic Test Tube RackPlastic Test Tube Rack

Water Trough for Collecting GasWater Trough for Collecting Gas

Wire Gauze with Ceramic CenterWire Gauze with Ceramic Center

Wire Triangle with PorcelainWire Triangle with Porcelain

Centigram BalanceCentigram Balance

Analytical BalancesAnalytical Balances

Buret on ring standBuret on ring stand

Combustion spoonCombustion spoon

DesiccatorDesiccator

Florence flaskFlorence flask

Gas collecting tubeGas collecting tube

Mortar and PestleMortar and Pestle

Pipets and Pipet bulbPipets and Pipet bulb

ThermometersThermometers

Triangular file for glass cuttingTriangular file for glass cutting

Wash bottleWash bottle

Volumetric flasksVolumetric flasks

Separatory funnelSeparatory funnel

Buchner funnel and side arm filter flaskBuchner funnel and side arm filter flask

Mathematics of ChemSI Prefixes can be used with SI bases to form units that are < or > than the base unit by multiples of 10.

Prefix Symbol Multiply root byMega M 1,000,000

Kilo k 1,000

Hecto h 100

deka dk 10

BASE g,l,m 1

deci d .1

centi c .01

milli

micronano

m

μ

n

0.001 1/1000

.000001 1/1000000

.000000001

Using dimensional analysis to convert from one unit to the next

Example – How many minutes are in 3 hours?

3 hours 60 min hour

X = 180 min

Only unit left is the unit we want as our final answer

Hours cancel out

conversion factor

How many hours are in 230 minutes?

230 minutes 60 min hour

We want hours in the numerator, and we want minutes to cancel out

Flip the conversion factor 60 min hour

Hour60 minsame as

230 minutes Hour 60 min

X = 230 hours 60

= 3.8 hours

Ex. 0.19 cm = ? m

0.19 cm x1 m100 cm

This is a conversion factor!!! The top and the bottom number are the same amount!!

Ex. 37 mg = ? g

37 mg

x 1g

1000 mg

Ex. 37 mg = ? kg

37 mg

x 1 g1000 mg

x 1 kg1000 g

Practice

9.923 km = ? m

232 ml = ? dkl

320 hr = ? sec

Sometimes it is easier to use more than one conversion factor!!!

If we sell 2 cars per hour, and we make a profit of $100 for every three cars, how much can we make in 3 hours?

STEPS1. Write out all the numbers with the units2. Write out the units for the answer3. Flip the fractions to allow the units to cancel out4. Multiply and divide

2 carshour

$ 1003 cars

3 hours = $

$ 200

If there are 5 oranges in a box, and each orange weighs

0.5 pounds, and the price is $1.25 per pound, how many

boxes can we buy with $3.00?

5 oranges 1 box

orange0.5 lbs

$1.25 lb

$3.00

0.96 boxes

What are the conversion factors?

Accuracy

- How close a measurement is to an accepted value

- BP of water is 100 C

Precision

- How well a measurement can be repeated

- Measurements are very close to one another

Ex. 1.11, 1.12, 1.10

Uncertainty in Measurement

When taking measurements, measure to the furthest confirmed data point and then estimate one more. The last digit is uncertain.

All measurements vary in their degree of accuracy.

1 M

1.1 M

1.12 MMore accurate

Signigicant Figures

More sig.figs. = More accurate measurement

When making measurements, we are certain of all numbers except the last

- the numbers known with certainty plus one uncertain number

0 1 2 3 4 5 6 7cm

Measure the length as accurately as possible

We know it is between 6 and 7, so we can guess it is 6.6 cm long

a.

706050403020100

b.

46oC

1.81.71.61.51.41.31.21.1

c.

1.54 ml

The last digit is uncertain. We have to make an educated guess as to its value!!!

Why is it uncertain?

1) Limits of the measuring device2) Human error

Rules for Counting Sig Figs in a measurement

1. All nonzero digits are significant-They are always part of the measurement

2. Zeros are significant except in two cases

a. When there is no decimal, the ending zeros are not significant

210 15,000 10,0002 sig figs

2 sig figs

1 sig figs

Ex. 5.37 3 s.d.

40.2935 s.d.

b. With numbers less than 1, the beginning zeros are not significant

0.215 0.0025 0.005203 sig figs

Practice - determine the number of sig figs in the following numbers

432 730 65.0 8400 0.004501 0.850 101.0

3 2 3 2 4 3 4

Calculating with Sig Figs

1. Adding and subtracting

1.) Add or subtract normally

2 sig figs

3 sig figs

2.) Round sum or difference so that it has the same number of decimal places as number having the fewest

632.62.71+

43.7176.952

+ 4635.31635.3 124.662125

2. Multiplication and Division

Multiply or divide normally, then round off to the LEAST NUMBER OF SIG FIGS

16.0x 2.0

32.0

3 sig figs2 sig figs

The answer can only have 2 sig figs

32

18.009.00

=

The answer can only have 3 sig figs

4 sig figs3 sig figs

2.00

Examples - Perform the following calculations, then leave your answer in the proper number of sig figs.

a. 47.0 + 2.938 =

b. 63.8 x 2.0 =

c. 1,400 2.00 =

d. 6.35 + 2.9314 + 120 =

e. 0.250 x 120.0 =

49.938 49.9

127.6 130

700 700.

129.2814 130

30 30.0

f. (1.2 x 103)(6.4 x 104) = 7.68 x 107 7.7 x 107

Scientific Notation

A x 10n

A is a number between 1 and 10

n is an integer

101 = 10

100 = 1

10-1 = .1

So a number written in S.N. could look like

2.2 x 101 =

5.88 x 10-1 =

22 .588

Why do it?

602,000,000,000,000,000,000,000

Easier to write as 6.02 x 1023

Positive Exponent= number of times decimal is moved to the right

Negative Exponent

= number of times decimal is moved to the left

- The bigger the negative the smaller the number

- in scientific notation all numbers written in first factor are significant

Multiplication and Division with Scientific Notation

Multiplication

1. Multiply ordinary parts of number

2. Add exponents

3. Express answer with proper form ( only one number to the left of the decimal point)

4. Make sure the answer has same number of sig. Figs as factor with the least.

Ex. 2.40 x 104 x 6.3 x 102

15.120 x 106 NOPE!!!

1.5120 x 107 Not yet!!

1.5 x 107

Absolutely!!!

Division

1. Divide first factors

2. Subtract exponent in denominator from exponent in numerator

3. Express in proper form ( 1 digit left of decimal )

4. Make sure proper number of sig. figs

Ex. 6.4 x 1061.7 x 102

3.8 x 104

Addition and Subtraction

1. Manipulate the numbers so that they have the same exponents

2. Add/subtract the first numbers and then add the x by 10n to the power

3. Make sure answer is in proper scientific notation, don’t worry about sig figs.

Ex. (8.41 x 103) + (9.71 x 104) =

(6.3 x 10-2) – (2.1 x 10-1)