Intro to ANalytical Chem

Analytical Chemistry

the science of chemical characterization and measurement

What are the 2 branches of analytical chemistry?

1. Qualitative Analysis

2. Quantative Analysis

The Analytical Process

the standardized means that allow analytical chemists to perform a procedure

Aliquot

a small portion, typically of a solution or liquid

Analyte

substance being measured in an analytical procedure

Aqueous

a substance dissolved in water

Concentration

a measure of the amount of substance present in a unit amount of mixture

Heterogeneous

a sample consisting of more than one pure substance and more than one phase. For example, blood consists of cells and plasma.

Homogeneous

a sample consisting of more than one pure substance with properties that do not vary within the sample

Qualitative Analysis

a chemical analysis that detects the presence of a substance in a sample

Quantitative Analysis

a chemical analysis that determines the concentration of a substance in a sample

What are the steps of the Analytical Process?

1. Formulating the Question

2. Selecting Analytical Procedures

3. Sampling

4. Sample Preparation

5. Analysis

6. Interpretation

Formulating a Question (w.r.t. the Analytical Process)

• the question must be specific, and able to be answer thru chemical measurements

• determine whether its quantative or qualitative

Selecting Analytical Procedure (w.r.t. the Analytical Process)

- take a sufficient # of samples

- samples must be representative of entire amount

the process of selecting representative material to be analyzed

Sample Preparation (w.r.t. the Analytical Process)

What does a Desiccator do?

keeps dried sample from reabsorbing moisture

What is a way to describe good glassware? What are examples of good glassware?

Less precise

• only 2 decimal places (on scales)

• grad. cylinders

What is a way to describe great glassware? What are examples of great glassware?

• need at least 1 decimal place

What conditions come with TD glassware?

• dnt

• DON’T blow out tip

Define Solution

Define Solvent

Define Solute

Molarity

• # of moles (n)/L_soln

• Temp.-dependant

• Remeber:

Step 4 Of Analytical Process

sample preparation: deal with interfering species, sample too concentrated, sample too dilute

Step 5 Of Analytical Process

analysis: multiple, repeated measurements; reduce data to numerical result

Step 6 Of Analytical Process

interpreting and reporting: interpret final results, perform appropriate statistics, draw conclusions

SI Base Unit For Length

metre (m)

SI Base Unit For Mass

kilogram (kg)

SI Base Unit For Time

second (s)

SI Base Unit For Electric Current

ampere (A)

SI Base Unit For Temperature

kelvin (K)

SI Base Unit For Amount Of Substance

mole (mol)

SI Base Unit For Luminous Intensity

candela (cd)

Frequency (SI Derived Unit)

hertz (Hz)

Force (SI Derived Unit)

newton (N)

Pressure (SI Derived Unit)

pascal (Pa)

Energy (SI Derived Unit)

joule (J)

Power (SI Derived Unit)

watt (W)

Electric Charge (SI Derived Unit)

coulomb (C)

Electric Potential (SI Derived Unit)

volt (V)

Electric Resistance (SI Derived Unit)

ohm (Ω)

Purpose Of SI Prefixes

express large or small numbers in easier way; prefix usually chosen so number is less than 1000

Giga (G)

10^9

Mega (M)

10^6

Kilo (k)

10^3

Centi (c)

10^-2

Milli (m)

10^-3

Micro (µ)

10^-6

Nano (n)

10^-9

Pico (p)

10^-12

Femto (f)

10^-15

Litre (L)

× 10^-3 m3

Millilitre (mL)

× 10^-6 m3

Angstrom (Å)

× 10^-10 m

Pound (lb)

× 0.45359 kg

Dyne (dyn)

× 10^-5 N

Atmosphere (atm)

× 101 325 Pa

Bar

× 10^5 Pa

Torr (1 mmHg)

133.332 Pa

Electron Volt (eV)

1.60218 × 10^-19 J

Calorie (cal)

× 4.184 J

Celsius (°C)

K − 273.15

Food Calorie (Cal)

1000 cal

Charge Of Electrons

1 C = 6.24 × 10^18 electrons

Unit Conversion Warning

when units are squared or cubed, take that into account; 1 km3 = 10^9 m3, not 1000 m3