1. G-CHEM Fundamentals

Question 1

what are the 6 SI base units used in science?

Answer 1

meter - m - length
kilogram - kg - mass
second - s - time 
mole - mol - quantity 
kelvin - K - temperature
ampere - A - electric current

Question 2

what is a liter, what is an angstrom?

Answer 2

1000 L = 1 m ^3
1 L = 1000 cm^3

A = 10^-10
atomic radii and bond length are typically 1-3A

Question 3

what is the SI unit for volume? what is molarity?

Answer 3

SI unit for volume is cm^3

molarity (M) is a measure of concentration, which is moles/liter (despite cm^3 being the SI unit of volume)

Question 4

how many orders of magnitude is a centimeter longer than an angstrom?

Answer 4

1 A = 10^-10 meters
1 cm = 10^-2 meters

orders of magnitude = 8

Question 5

what is the density of water?

Answer 5

1 g / cm^3

Question 6

write out the chemical formula for 
ammonium 
hydronium 
phosphate 
acetate

Answer 6

ammonium - NH4+
hydronium - H3O+
phosphate - P04 (3-)
acetate - CH3CO2-

Question 7

what is avogadros number? what is its significance?

Answer 7

6.02 x 10^23

this is the number of atoms needed to obtain 12 grams of carbon-12. This number allows us to convert atomic mass units and grams.

Question 8

1 mole of sodium has a mass of?

Answer 8

1 at of sodium has a MW of 23 amu’s. Therefore, 1 mole of sodium is 23 grams.

Question 9

what is the formula for molarity?

Answer 9

M = moles of solute / liters of solution.

Question 10

what are stoichiometric coefficients?

Answer 10

stoichiometric coefficients give the ratios of the number of molecules/moles needed for a reaction (NOT the mass). These coefficients allow reactions to be balanced, as required by the law of conservation of mass.

Question 11

what is an oxidation state?

Answer 11

an oxidation state/number explains an atom’s or molecule’s ownership over its electrons. If a bond is formed, giving up ownership results in an increase in OS, while accepting ownership results in a decrease in OS.

Question 12

what are the seven oxidation state rules, in order?

Answer 12

1. OS of any atom in its standard state = 0
2. sum of OS’s in any molecule must equal the charge of that molecule
3. Group 1 metals = +1, group 2 metals = +2
4. fluorine is -1
5. Hydrogen is +1 when bonded to something more EN than carbon, -1 when less, and 0 when bonded to carbon
6. oxygen is -2
7. halogens are -1, oxygen family elements are -2

the order of rules matters, higher takes precedence

Question 13

when is the OS of oxygen -1 instead of -2?

Answer 13

in peroxides when oxygen is binding to itself. (H2O2)

Question 14

What are the most electronegative elements?

Answer 14

FONClBrISCH

hence rule 5 about hydrogen oxidation states.

Question 15

t or f, metals can assume a negative oxidation number

Answer 15

false, metals will never has a negative OS

Question 16

What is the oxidation state of O2?

Answer 16

OS = 0
oxidation state rule 1 states that elements in their standard state have an OS of 0.

oxygen is diatomic and exists naturally as O2.