Chemistry - equations

Question 1

Density

Answer 1

mass/volume

Question 2

Force

Answer 2

Mass × acceleration

Question 3

Energy

Answer 3

F × d or (m × a × d)

Question 4

Potential Energy

Answer 4

m × g × h

Question 5

Kinetic Energy

Answer 5

0.5 × m × v^2

Question 6

Electromagnetic Energy

Answer 6

k × ( (q1 × q2)/r ) where k = constant q = charge r = distance of two charges

Question 7

Total Intensity

Answer 7

(5.67E-8 W × mE-2 × kE-4) × TE4 where t = temperature

Question 8

Avogadros Number (how used)

Answer 8

Moles <-> number of particles (atoms/molecules)

Question 9

Percent Composition

Answer 9

(mass of an element in a sample/total mass of the sample) × 100

Question 9

Speed of light (c)

Answer 9

2.9979E8 m/s

Question 10

c=

Answer 10

λ × v

Question 11

The frequency of light with a wavelength of 258 nm is?

Answer 11

1.16E15 1/s

Question 12

E =

Answer 12

hv where h = planks constant v = frequency

Question 13

Calculate the energy of the red light photon with a wavelength of 7000 angstroms (1 angstrom = 1E-10 m)

Answer 13

3E-19 J

Question 14

ΔE =

Answer 14

-2.178E-18 J ( (1/n^2 final) - (1/n^2 initial) )

Question 15

1/λ =

Answer 15

Rydberg constant ( (1/n^2 final) - (1/n^2 initial) )

Question 16

Calculate the wavelength of light emitted when an electron of hydrogen moves from n=5 to n=3

Answer 16

1.281E-6 m

Question 17

Heisenberg Uncertainty Principle

Answer 17

∆x × ∆(mv) ≥ (h/4π) where x = position of the particle ∆x = uncertainty in the particle’s position ∆(mv) = uncertainty in the particles position

Question 18

If the maximum velocity of an electron in copper wire is about 1.7E8 cm/s with an uncertainty ≤ 1.0% (of velocity), how accurately can the electron’s position be determined? In other words, what is the uncertainty in the position of the electron (in meters)? Where mass of an electron = 9.10938188E-31 kg

Answer 18

∆x ≥ 3.4E-9 m

Question 19

Ephoton =

Answer 19

hv = (hc)/λ

Question 20

The speed of an electron emitted from the surface of a sample of potassium by a photon is 668 km/s. What is the kinetic energy of the ejected electron? Where mass of an electron = 9.10938188E-31 kg

Answer 20

2.03E-19 J

Question 21

The work function (threshold) of the potassium is 2.29 eV. What is the wavelength of the radiation that caused photo-ejection of the electron? Where 1 eV = 1.602E-19 J

Answer 21

3.48E-7 m

Question 22

The speed of an electron emitted from the surface of a sample of potassium by a photon is 668 km/s. What is the longest wavelength of electromagnetic radiation that could eject electrons from potassium?

Answer 22

5.41E-7 m

Question 23

De Broglie Equation λ =

Answer 23

h/(m × v) where v = velocity

Question 24

Calculate the wavelength of a baseball with a mass of 150 g moving with a speed of 70 mi/hr.

Answer 24

1E-34 m

Question 25

Calculate the wavelength of a electron with a mass of 9.1E-31 kg moving about the hydrogen atom with a speed of 2,200 km/s

Answer 25

3.3E-10 m

Question 26

3p5

Answer 26

n = 3, ℓ = 1, mℓ = 0, ms = -1/2

Question 27

5f13

Answer 27

n = 5, ℓ = 3, mℓ = 2, ms = -1/2

Question 28

Electron configuration of P

Answer 28

1s^2 2s^2 2p^6 3s^2 3p^3

Question 29

For principal quantum level n=3, determine the number of allowed subshells (different values of ℓ), and give the designation of each.

Answer 29

of allowed subshells = 3
ℓ = 0 (3s)
ℓ = 1 (3p)
ℓ = 2 (3d)

Question 30

For ℓ = 2, determine the magnetic quantum numbers (mℓ) and the number of orbitals

Answer 30

magnetic quantum numbers = -2, -1, 0, 1, 2
number of orbitals = 5

Question 31

Photoelectric Effect

Answer 31

Ekinetic = hv - hv0

Question 32

The minimum energy required to eject an electron

Answer 32

Hv0