UGA Chem 1211L Lab Practical Spring 2022

beaker

A lipped cylindrical glass container is used for holding or mixing liquids with a pouring spout; some have graduations indicating an APPROXIMATE volume of contents

Erlenmeyer flask

A conical, flat-bottomed laboratory flask with a narrow neck used for holding or mixing liquids; some have graduations indicating APPROXIMATE volume of contents

filtering flask

A heavy wall flask designed for use in suction (vacuum) filtration; has a side hose connection to attach vacuum tubing

volumetric flask

A flask used for preparations of solutions, which are calibrated to contain a specific volume of liquid or solution

test tube

A round bottom glass tube used to contain or heat small amounts of material

volumetric pipet

A pipet calibrated to deliver an EXACT amount of solvent or solution

Mohr pipet

A graduated pipet to deliver solution

buret

A graduated glass tube with a tap at one end for delivering/dispensing known volumes of a liquid, especially in titrations through a stopcock

funnel

A pipe with a wide (often conical) mouth and a narrow stem is used to channel liquid or fine-grained substances into containers with a small opening

Buchner funnel

Used with vacuum filtration

Powder funnel

Funnell with a short, wide stem

rubber policeman

A rubber tip with a flattened end used on a glass rod for scraping solids from containers

spatula/scoopula

Labratory utensils used for handling small amounts of solid chemicals

graduated cylinder

A measuring device, graduated to contain liquids or solutions; tall versions are equipped with a plastic bumper to prevent shattering if it is knocked over

dropping pipet

A medicine dropper used to dispense liquids in drop-wise amounts

Pasteur Pipet

Small drops, usually disposable

watch glass

A glass dish that can be used for evaporation of small amounts of liquids, for studying small amounts of solids (weighing, etc.), or covers for beakers

bunsen burner

A burner that contains a needle valve for gas flow regulation

ring stand support

Consists of a heavy base with a metal rod for supporting apparatus for a variety of laboratory operations

utility clamp

Adjustable clamp for holding a test tube, buret, or other apparatus

extension clamp

Used with a clamp holder, allows for more varaition in positioning than a utility clamp

3-prong clamp

Used with a clamp holder, allows for more versatility in holding different types of apparatus

extension clamp holder

Used to attach an a extension clamp to a ring stand support or support frame

support ring

A ring designed as a base support for beakers and flasks when heated on a ring stand support

double buret holder

A double clamp for holding burets

Wire gauze (ceramic center)

a support surface to be used with a ring support or tripod to provide uniform heat distribution

stir bar

A teflon coated magnet used for mixing reactions

boiling chip

A tiny, unevenly shaped piece of calcium carbonate or silicon carbide added to liquids to make them boil more calmly

magnetic stirrer/hot plate

A device used to stir and heat reactions sat on top of it

pH and mV meter / thermometer

Used to measure

Test tube holder

a clamp secures the test tubes in place

beaker tongs

Wide-jaw tongs for holding beakers

crucible tongs

Tongs with oval opening in jaws for holding crucibles; tips used for handling crucible covers

stirring rod

A piece of laboratory equipment used to mix chemicals and liquids for laboratory purposes; usually made of solid glass

evaporating dish

A small ceramic dish in which liquids are heated over a flame so that they evaporate, leaving a solid residue

tweezers

Small metal instruments that are usually held between the thumb and index finger, are used for plucking, holding, or manipulating, and consist of two legs joined at one end

spectrophotometer

An apparatus for measuring the intensity of light in a part of the spectrum, especially as transmitted or emitted by particular substances.

T

T/F: Volumetric glassware have been calculated to be precise in their volume.

F- approximate

T/F: Beakers are accurate tools to measure volumes.

n+1 decimal place

If a laboratory instrument is marked to nth decimal place, record data to the ___________.

1

1 ml = ______ cm³

1.00g/mL

Density of pure water at STP

standard solution

A solution containing a precisely known concentration of an element or a substance

5.000%

If using a 100mL of water (solvent) and 5.000 grams of sugar (solute), a __________ sugar solution would be prepared.

law of conservation of mass

The mass of the reactants consumed must equal the mass of the products generated

law of definite proportions

A given chemical compound always contains its component elements in fixed ratio (by mass) and does not depend on its source and method of preparation

atomic theory

Matter is composed of discrete units called atoms and combine in a ratio of small whole numbers

electrolysis

Chemical decomposition produced by passing an electric current through a liquid or solution containing ions, which would otherwise not happen

decant

To gradually pour (liquid or a solution) from one container into another, especially without disturbing the sediment at the bottom

filtration

One component dissolves in water. Mixture is separated by filter funnel and filter paper. Solid is collected on paper. Liquid flows through paper and becomes filtrate.

sedimentation

When solid particles settle out; heavier solids fall to the bottom of the slurry or suspension

centrifugation

Use of centrifugal force for the sedimentation of heterogeneous mixtures

distillation

Process of separating components from liquid mixtures through vaporization and condensation, based on different boiling points of components in the mixture

evaportation

Used when the solid present in the liquid is non-volatile. Solution is heated. Solvent evaporates and solid is left as residue

chromatography

Different constituents when dissolved in a solvent will travel at different rates on the paper and become separated; has a mobile phase and a stationary phase

coagulant

A substance that causes a liquid to change to a solid or semisolid state

molar absorptivity

The measurement of how strongly a chemical species absorbs light at a given a wavelength (ε in the equation for the Lambert-Beer law)

Lambert-Beer law

The absorption of light as it passes through a solution is proportional to the concentration of the absorbing species, the length of the light path, and the fundamental property of the material (the molar absorptivity)

A=εlc

Equation for Lambert-Beer law

light path length

l in Lambert-Beer law

concentration

c in Lambert-Beer law

transmittance

The fraction of light that passes through the sample in spectophotometry

T=I/Io

Equation for transmittance

absorbance

A logarithmic measure of the amount of light absorbed (at particular wavelength) as the light passes through a sample or substance

A=log(1/T) or A=-log(I/Io)

Equation for absorbance

calorie

The energy needed to raise the temperature of 1 gram of water through 1°C

law of conservation of energy

In a closed system, i.e., a system that isolated from its surroundings, the total energy of the system is conserved

percent yield

The percentage of actual to theoretical

(actual/theoretical)×100

Equation for percent yield

percent error

The difference between the estimated number and the actual number when compared to the actual number expressed in percent format

(theoretical-actual)/actual)×100

Equation for percent error

r^2

Symbol for the linear regression of data

The precision of a measurement is

a measure of the reproducibility of a set of measurements

Absolute error is the difference between

measured value and actual value

standard deviation

a measure of the amount of variation within a set of values, how close are they to the mean?

density of penny = (density of copper 8.92g/cm3 * % of Cu [x] ) + (density of zinc 7.14 g/cm3 * % of Zn [1-x] )

percent composition of the penny

Density

Intensive, doesnt depend on quantity of material, M/V

When HCl reacts with new penny, whats chemical equaiton?

2 HCl (aq) + Zn (S) yields ZnCl2 (s) + H2 (aq)

Calculate percent sugar in cola using linear regression

y = density x = percent sugar concentration

Filtration is

one component dissolves in a solvent and others remain in the solid-state, separated with a filter funnel and filter paper, solid is on paper and liquid flows through paper to be filtrate

Sedimentation

Solids will settle to bottom of solid-liquid heterogeneous mixture

Evaporation is

separation of homogeneous mixtures, like sodium chloride can be isolated from salt water by evaporating the water. SOlution is heated and solvent evaporates, solid residue is left

Centrifugaiton

use of centrifugal forces for the sedimentation of heterogeneous mixtures

Distillaiton

seperation through vaporization and condensation, based on different boiling points of liquids

Paper chromotography

Dissolved consituents will travel at different rates on paper and separate in mobile phase till stationary phase

Separation of mixture experiment

1. Iron fillings by magnet

2a. Vacuum filtration system separates solid calcium carbonate and silicon dioxide from watered down solution.

2b. Add HCl to disolve the CaCO3, then vacuum filtrate the silicon dioxide again

3. Erwin meyer glass moves to hotplate to evaporate water from NaCl.

Found the masses of 3/4, subtract from initial mass to find SiO2. Find mass percent

Mass percent of CaCO3

Mass of CaCO3 / Mass on unknown x 100

Percent composition of Si

MM of Si / total mass of SiO2 = percent comp of Si then multiply by mass percent of SiO2 then by 100 for percentage

Ethanol disolves

Sodium Chloride but not sodium bicarbonate

Coagulation

removes dirt and other particles in water

Potassium Alum, an inorganic coagulent used to remove negatively charged particles that are in suspension in water because they nutrilize them and metal hydroxide precipitates of the aluminum ion formed, trapping the suspended particles and settle to the bottom, not filtration can be used for sedimentation

KAl (SO4)2 * 12H2O

Aluminum metal is oxidized to

Al 3+ via strong base, forming Al(OH)4-1, with K to neutralize and hydrogen gas.

Add more H2SO4 to form

Al3+ solutions in water. aluminum ions combine with potassium and sulfate to crystalize

Then a strong acid (H2SO4) is used to form

aluminum hydroxide (Al(OH)3)

Percent yield is

actual / theoretical x 100

Sulfate is in our product because

SO4 2- (aq) + Ba 2+ (aq) → Ba SO4

The greater the amount of phosphate ions in water analysis, the more intense yellow color and then

the spectrophotometer determines the absorbtion

Lambert-Beer Law

Absorbtivity= molar absorbivity x light path length x concentration, a direct relationship is shown

Absorbance is inverse of transmittence

A = log (1/T)

Cuvette

goes in a spectrophotometer