CHEM 1212 FINAL

Exclamation Point (icon)

Irritant to skin and eyes, skin sensitizer, toxic, respiratory tract irritant

Test tubes pouring on metal and hands (icon)

Corrosive to skin and metal

Fire (icon)

flammable, emits flammable gasses, pyrophoric

O with fire (icon)

oxidizer, oxidizing agent

Human body with gas inside (icon)

general health hazard, respiratory sensitizer, carcinogen, organ toxicity

Dead fish and dead tree (icon)

aquatic toxicity, environmental hazard

Skull and crossbones (icon)

Severe to fatal toxicity

No Icon

moisture sensitive, hygroscopic (absorbs water from air)

Lachrymator

Causes eyes to produce tears

Corrosive

irreversibly destroys living tissue or metal upon contact

Irritant

chemical causes dryness, itching, or sensitivity

Carcinogen

chemical suspected or proven to cause cancer

Toxic

may cause harm through ingestion, inhalation, or skin absorption

PPE (Personal Protection Equipment)

• Splash Proof Goggles

• Lab Apron (cover as much skin as possible)

• Sneakers/loafers/boots

Proper Disposal

Uses pipet - trash can

Reaction mixture - appropriate waste container

Chipped beaker - broken glass box

Used filter paper - trash can

Excess chemical - waste container

Density Formula

mass(g)/volume(ml)

Solubility

the ability of a solid or gas to dissolve in a liquid

Solvent

the solution that does the dissolving

Solute

the substance being dissolved

Miscible

when two liquids mix completely together

Immiscible

when two liquids do not mix together and form layers

Physical Properties

• melting point

• boiling point

• color of liquid

Chemical Properties

• ability to dissolve metals

• ability to react with oxygen

• ability to dissolve in water

Combinations

A + B → AB

two elements come together to form one compound

Decomposition

ABC → AB + C

one species decomposes into two or more species

Single Displacement

AC + B → A + BC

one element displaces an atom in a compound to form a new compound, while the displaced atom is converted to its elemental form

Double Displacement

AC + BD → AD + BC

the two cations are exchanged and two new compounds are formed

Oxidation-Reduction

two half reactions added together, one species loses electrons and the other gains

Actual Yield

amount of product recovered in the experiment

Theoretical Yield

amount that could be produced from limiting reagent if the reaction were 100% efficient

Percent Yield

the ratio of the actual yield to the theoretical yield

Moles of Copper(II) Saccharinate

(mass)x(1 mole Cu(C2H3O2)2xH2O/199.65 g Cu(C2H3O2)2xH2O )

Moles of NaC7H4SO3N·H2O

(mass)x(1 mole NaC7H4SO3N·H2O /223.18 g NaC7H4SO3N·H2O)

Moles of Product

(mol Cu(C2H3O2)2xH2O)x(1mol/1mol)

Mass of Product/Theoretical Yield

(mol Cu(C7H4SO3N)2(H2O)4x2H2O)x(535.59g product/1 mol product)

Percent Yield Equation

actual yield/theoretical yield x100%

Limiting Reagent

the reactant which is completely consumed or used up during the reaction

Experiment 3 Error-

Only leaving the beaker in the ice bath for 5 minutes instead of 25 minutes

Lowers the actual yield

Experiment 3 Error-

Weighing the crystals while the crystals are still wet

Raises the actual yield

Experiment 3 Error-

Washing with hot water

The actual yield will decrease since part of the product will dissolve and not be recovered as a solid. Since actual yield is in the numerator, the percent yield will also decrease.

Experiment 4 Error-

Didn't rinse the product at all during filtration

Raises the actual yield

Experiment 4 Error-

Used a dirty spatula and got some NiCl2*6 H2O in with the product during weighing

Raises the actual yield

Assume NiCl2·6 H2O is LR

(mass of NiCl2·6 H2O/237.69 NiCl2) x 309.9 g [Ni(en)3]Cl2

Assume [Ni(en)3]Cl2 is LR

(molarity x volume) x 1 mol/3 mol x 309.9 g

Experiment 4-

If neither is the LR the color of the product will be

Pink-Violet

Analyte

species of interest

Titrant

species being added

acid-base indicator

species that changes colors at different pHs

Moles of H3C6H5O7 (citric acid)

Molarity of NaOH x mL of NaOH x (1L/1000ml) x (1mol/3mol)

Mass of H3C6H5O7

mol H3C6H5O7 x 192.12 g H3C6H5O7

mg of H3C6H5O7

mass x (1000mg/1g) x (1/ml of juice)

Experiment 5 Errors-

Over-titrating the end point (adding too much titrant)

Raises the value of mg citric acid/mL juice

Experiment 5 Errors-

Adding 20 mL of water to the Erlenmeyer flask before titration

No Effect

Experiment 5 Errors-

Using the Molarity of NaOH used in the practice problem (0.1065 M) instead of the Molarity of NaOH recorded on the bottle (0.121 M) in the calculations

Lowers the value of mg citric acid/mL juice

Experiment 5-

Under-titrating

Since the volume of titrant is too small, multiplying by a small number in the calculation of citric acid makes the mass of citric acid too low.

The reaction was stopped too quickly (before reaction was complete).

Aliquot

a portion of the standard

Standardization

The method of determining the concentration of the titrant by using a known amount of a standard compound

Molarity of Ascorbic Acid (standard)

mass H3C6H5O7/176.14 g C6H8O6/L solution

Molarity of DCP (standardization of titrant)

mol DCP/mL DCP x 1000mL

mg of Vitamin C

M DCP x L DCP x 176.04 g C6H8O6 x 1000mg

mL of juice

recommended mg C6H8O6 x mL juice/ mg C6H8O6

Experiment 6 Errors- overtitrating the end point in Part III affect the value of mg of Vitamin C

Raises the value of mg of Vitamin C

Experiment 6 Errors- Using a lower Molarity value of ascorbic acid affect the calculated Molarity of DCP?

Lowers the value of Molarity of DCP

Experiment 6 Errors-

Using lower Molarity value of DCP affect the calculated mg of Vitamin C?

Decreases the value of mg of Vitamin C

Experiment 6-

Over-titrating

Too much DCP was added in the titration, causing the Molarity of the ascorbic acid to be lowered

With a lower molarity of DCP, the amount of Vitamin C will also be lower even if the titrations in Part II were done correctly

Nonelectrolyte

does not conduct electricity (H2O)

Weak Electrolyte

any substance that when dissolved in water partially dissociates into ions, so a few ions are present and it conducts electricity weakly

Strong Electrolyte

any substance that when dissolved in water totally dissociates to form many ions, and conducts electricity strongly.

Equivalence Point

there are equal moles of the two reactants, this solution will contain only products (no ions present).

Find M from Titration Data

M(a) x ml(a) x (1L/1000ml) x mole ratio / mL(b) x (1000ml/1L)

H2SO4

Strong electrolyte