Intro to Analytical Chemistry

Question 1

define analytical chemistry

Answer 1

science that is concerned with the separation, identification, and finding out how much of a certain components creates a sample (ex. concentration)

Question 2

what are the 2 branches of analytical chemistry?

Answer 2

qualitative and quantitative analysis

Question 3

define qualitative analysis

Answer 3

identifying what the sample is. mainly concerned with the descriptions of elements, compounds and structural units.

Question 4

define quantitative analysis

Answer 4

finding out how much of something is in the sample.

Question 5

explain 3 of the different applications analytical chemistry can have in science.

Answer 5

chemical analysis: Bringing it down to the basics
material analysis: testing raw materials
environmental analysis: looking at the environment and contaminations
forensics: how it can relate to the law with drug and trace analysis

Question 6

define aliquot

Answer 6

a small portion, usually solution or liquid

Question 7

define analyte

Answer 7

substance being measured, things of interest

Question 8

define concentration

Answer 8

a measure of the amount of substance present in a unit of mixture (NOT JUST IN MOLARITY)

Question 9

define heterogeneous

Answer 9

sample with more the one pure substance and more than one phase (ex. mixing sand and water together)

Question 10

define homogeneous

Answer 10

sample with more tahn one pure substance with properties that do not vary (ex. water or air)

Question 11

what are the 6 steps of the analytical process?

Answer 11

1. formulating a question: specific question to be answer with chemistry
2. selecting the analytical procedures: find, modify, and create new procedures to make the requirement measurements
3. sampling: selecting representative material to be analyzed, enough but not too many (ryan renolds examples)
4. sample preparation: converting the sample into a suitable form for the analysis
5. analysis: repeated measurements to rule out error, and complete again to show that it can be repeated
6. interpretation: perform statistics and draw conclusions

Question 12

what does the SI unit: A, represent?

Answer 12

A = ampere, it is the quantity of an electric current

Question 13

what does the SI unit: cd, represent?

Answer 13

cd = candela, quantity of luminous intensity

Question 14

what are the SI units for frequency, force, pressure, power, electric charge, potential and resistance?

Answer 14

frequency: hertz, Hz
force: newton, N
pressure: pascal, Pa
power: watt, W
electric:
- charge: coulomb, C
- potential: volt, V
- resistance: ohm, Ω (omega)

Question 15

what are the 8 SI prefixes, from smallest to largest?

Answer 15

pico (p, 10^-12)
nano (n, 10^-9)
micro (μ, mu, 10^-6)
milli (m, 10^-3)
centi (c, 10^-2)
kilo (k, 10^3)
mega (M, 10^6)
giga (G, 10^9)

Question 16

what is the saying for the SI prefixes from smallest to largest?

Answer 16

Please, -12
Nanna, -9
My, -6
Muffin, -3
Container, -2
Killed, 3
My, 6
Grandpa, 9

Question 17

define volumetric method

Answer 17

measures the volume of a solution containing sufficient reagent to react with the analyte

Question 18

define electroanalytical method

Answer 18

measures electrical properties such as potentials, current, and etc.

Question 19

define assay

Answer 19

process of determining how much of a given sample is the material indicated by its nmae

Question 20

what are the 2 main instruments for drying?

Answer 20

laboratory oven (to remove moisture) and desiccator (uses a desiccant, a drying agent, to isolate it from atmosphere)

Question 21

what are the 2 main instruments for measuring mass?

Answer 21

top-loading balance (0.01) and analytical balance (0.0001)

Question 22

what are the 4 approximate volume tools?

Answer 22

• graduated cylinder
• beaker
• Erlenmeyer flask
• paster pipet

Question 23

what are the 3 accurate volume tools?

Answer 23

• volumetric flask
• burette
• volumetric pipet

Question 24

define solution

Answer 24

homogenous mixture, only one phase but more than one component

solution = sovlent + solute

Question 25

define solvent

Answer 25

most abundant component in solution

Question 26

define solute

Answer 26

substance that is dissolved in a solvent to make a solution, minor component

Question 27

define atomic weight (AW)

Answer 27

number of grams containing avogardo’s number of that element’s mass. 6.02 x 10^23 particles/moles

Question 28

define molecular weight

Answer 28

sum of the atomic weights of the atoms in the molecule, adding all the atomic weights of the compound together

Question 29

explain molarity as a concentration

Answer 29

number of moles per one litre of solution changes with temperature cause of volume.

M= moles of substance/litre of solution

moles= mass of substance/molecular weight

Question 30

explain normality as a concentration

Answer 30

equal to the number of equivalents of solutes per litre of solution. mostly used with acids and bases

N = number of equivalents/1L of solution
N= molarity x n(reacting units per mole)

Question 31

define equivalent

Answer 31

Eq is equal to the number of reacting units.
1 equivalent = 1 mole of reacting unit

equivalent weight = molecular mass/ reacting units per mol
equivalents= weight of substance/ equivalence weight

Question 31

explain molality as a concentration

Answer 31

number of moles of a substance per kilogram of solvent, only used with melting and boiling points

m= mole fo substance/1kg of solvent

Question 31

define reacting unit

Answer 31

proton or electron. for acid-base, it is the number of protons that will be moved in the equation (write out the equation for the compound)

Question 32

explain what percent composition is

Answer 32

composition of a solution expressed in unit of analyte per 100 units of solution. Only expressed as weight/weight of volume/volume!

%weight= weight of solute/weight of solvent x 100
(same for volume)

Question 33

define ppm and ppb

Answer 33

parts per million: mass of substance/sample x 10^6

parts per billion: mass of substance/sample x 10^9

Question 34

what is the p function?

Answer 34

p(x) = -log(x) or 10^-p(x)

Question 35

what is a dilution factour?

Answer 35

used when a sample is too concentration or too diluted

diltution factour= volume 1/volume 2