Constants + Chem equations

Question 1

what is Avogadro’s number?

Answer 1

6.022 x 10^23

Question 2

What is Planck’s constant?

Answer 2

6.6 × 10^-34 m2 kg / s

Question 3

What is the formula for the energy of a photon?

Answer 3

E = hf

E = h x (c / λ)

h = planck’s constant = 6.6 x 10^-34

Question 4

B- decay, what occurs?

Answer 4

convert a neutron to a proton + an electron.
This is the most common

atomic number –> go up by 1
mass number –> stay the same
neutron number –> down by 1

Question 5

B+ decay, what occurs?

Answer 5

convert a proton to a neutron and a positron

atomic number –> down by 1
mass number –> stay the same
neutron number –> up by 1

Question 6

electron capture, what occurs?

Answer 6

capture an electron and combine it with a proton to form a neutron.

atomic number –> down by 1
mass number –> stay the same
neutron number –> up by 1

Question 7

formal charge calculation?

Answer 7

FC = valence - 1/2 bonding - lone

Question 8

list the order of IMF strengths

Answer 8

ion-ion > ion-dipole > Hydrogen bonding > dipole-dipole > D-ID > ID-ID (dispersion forces)

Question 9

t or f, radius increases to bottom left, acidity increases to bottom right.

Answer 9

true

Question 10

equation for the heat of a phase change and the heat not during a phase change?

Answer 10

q = ΔH phase change x n

q = mcΔT

C = c x m

Question 11

gibbs free energy?

Answer 11

ΔG = ΔH - TΔS

T in kelvin like always

Question 12

What is STP?

Answer 12

T = 273 K 
P = 1atm = 760 mmHg = 760 Torr

Question 13

Volume of an ideal gas at STP?

Answer 13

22.4 L

Question 14

what is Boyle’s Law?

Answer 14

Isothermal law for gases

when temperature is constant, PV=nRT

Volume varies with 1 / P

Question 15

What is Charle’s Law?

Answer 15

Isobaric law for gases

When pressure is constant, PV = nRT

Volume varies with T

Question 16

ΔG° = ? for

a. when considering equilibrium reactions
b. when considering redox reactions?

Answer 16

ΔG° = -RTlnk

ΔG° = -nFE°

Question 17

what is Faradays constant?

Answer 17

96,500 Coulombs which is equal to the charge of 1 mole of electrons

Question 18

Nernst equation?

Answer 18

We can take

ΔG = ΔG° + RTlnQ and plug in ΔG° = -nFE°

ΔG = -nFE + RTlnQ
(note its E not E° since we are now dealing with ΔG)

solve for E to get

E = E° + (RT / nF) lnQ

OFTEN RT/F = 0.06

E = E° + (0.06 / n) lnQ

Question 19

elementary charge (e)?

Answer 19

1.6× 10-19 coulombs

Question 20

Coulombs constant (k)?

Answer 20

9 x 10^9 Nm^2 / C^2

Question 21

density of water?

Answer 21

1000 Kg / m^3

1g / cm^3

Question 22

speed of light?

Answer 22

3 x 10^8 m/s

Question 23

speed of sound?

Answer 23

340 m/s

Question 24

threshold of hearing?

Answer 24

Io = 10^-12 W/m^2

Question 25

gas constant?

Answer 25

0.08 L atm / mol K