Exam 3

Question 1

Precipitation Reaction

Answer 1

1. Find the reaction of the chemical equation by swapping ions.
2. Balance the equation.
3. Write the phase of matter for each (aq, s, l)
4. Write the overall ionic equation by writing each element with charges and states of matter.
5. Find the spectator ions - match the ions on each side and cross them out.
6. Find the net ionic equation with whatever is left over.

Question 2

Strong Acids

Answer 2

1. HCl
2. HBr
3. HI
4. HNO3
5. H2SO4
   6.HClO4
6. HClO3

Question 3

Molarity

Answer 3

Molarity =
moles of solute/liters of solution

Question 4

Molality

Answer 4

Molality =
Moles of solute/Kg of solvent

Question 5

Mass Percent

Answer 5

Mass Percent =
Mass of solute/Mass of solution × 100%

Question 6

Calculate how many grams of a substance is needed to make a specific molar solution.

Answer 6

1. n = MV = Mol
2. Convert Mol to grams.

Question 7

Indicate what type of glassware is appropriate for making a molar solution.

Answer 7

Volumetric flask.

Question 8

Dilution Formula

Answer 8

M1V1 = M2V2
M stands for molarity
V is volume (ml or L - Must match)
Volume goes up, Molarity goes down

Question 9

Titration (Neutrilization Reaction)

Answer 9

1. M1V1 = M2V2
   OR
2. Write a balanced equation.
3. Convert moles of known solution to moles over liters of unknown solution using moles to moles ratio.
   0.25molNaOH/L x 0.0358L/1 x 1molHCl/1molNaOH x 1/0.0247L

Question 10

Top 4 gases in the atmosphere.

Answer 10

1. Nitrogen
2. Oxygen
3. Argon
4. Carbon Dioxide

Question 11

1 atm

Answer 11

760 torr

Question 12

760 torr to mmHg

Answer 12

760mmHg

Question 13

760 mmHg

Answer 13

14.7 psi

Question 14

1 atm to KPa

Answer 14

101.3KPa

Question 15

Boyles Law

Answer 15

P1V1 = P2V2

Question 16

Gay Lussacs Law

Answer 16

P1/T1 = P2/T2
Temperature has to be in Kelvin (+273.15)

Question 17

Charles Law

Answer 17

V1/T1 = V2/T2
Temperature must be in Kelvin(+273.15)

Question 18

Avogadros Law

Answer 18

V1/n1 = V2/n2
♤n = nf - ni
N in moles

Question 19

Ideal Gas Law

Answer 19

PV = nRT
Temperature in Kelvin(+273.15)
n = moles
Pressure = atm
R = 0.08206

Question 20

Daltons Law of Partial Pressure

Answer 20

Pt = Pa + Pb + Pc
Pa = XaPt
Xa = na/nt
Xa = Pa/Pt
P is pressure
Xa is mole fraction
N is moles

Question 21

STP

Answer 21

1. Find molar mass of element.
2. Convert to grams per liters.
   1 mole gas = 22.4L

Question 22

Change in energy

Answer 22

♤U = q + w
Q = + endo. W= + on the system
Q = - exo. W = - by the system

Question 23

First Law of Thermodynamics

Answer 23

♤U = Q - w

Question 24

Change of pressure of a gas

Answer 24

W = -P ♤V
W = work done
♤V = volumefinal - volumeinitial
P = pressure

Question 25

1 L × atm

Answer 25

101.3Joules

Question 26

Enthalpy of a Reaction

Answer 26

1. Multiple or reverse equation to match original. Whatever is done to equation must be done to sign and reaction number. 2. Combine the equations into one equation. Add the reactions together.

Question 27

Hess' Law

Answer 27

♤Hnet = sum of Hr

Question 28

Specific Heat Capacity for Water

Answer 28

C = 4.184 J/g°C

Question 29

Specific Heat Equation

Answer 29

Q = mC♤T Q = energy in Joules M = grams ♤T is final T - initial T = Celsius (C)1cal = 4.184J/g°C 1Cal = 1000cal = 1Kcal

Question 30

Order of wavelengths from long to short

Answer 30

1. Radio waves 2. Microwaves 3. Infrared radiation 4. Visible light 5. Ultraviolet 6. X-Rays 7. Gamma-rays

Question 31

What is the speed of light

Answer 31

3 × 10^8m/s

Question 32

Calculate wavelength of photon

Answer 32

¥ = c/v ¥ = wavelength C = speed of light (3×10^8m/s) v = frequency s^-1

Question 33

1 micro meter

Answer 33

10^-6m to 1 um

Question 34

Frequency of a photon

Answer 34

v = c/¥ v = frequency C = speed of light 3×10^8 ¥ = wavelength in meters

Question 35

Equation for when a photon changes energy level

Answer 35

E = -2.178×10^-18J(1/nf^2 - 1/ni^2)

Question 36

Frequency of a photon

Answer 36

v = |E/h| v = frequency|always positive|Hz or 1/seconds E = energy released h = 6.626×10^-34J×s

Question 37

Wavelength

Answer 37

¥ = c/v ¥ = wavelength in meters C = speed of light 3×10^8m/s v = frequency

Question 38

1 nanometer

Answer 38

10^-9 meters

Question 39

Calculate the energy of a photon with a specific wavelength

Answer 39

1. E = hc/¥ h = 6.626×10^-34J×s C = speed of light = 3×10^m/s ¥ = wavelength in meters 2. E = -2.178×10^-18(1/nf^2 - 1/ni^2) 3. Isolate the final energy level 4. Cross multiply. 5. Separate again. 6. Square root each side. ~answer should be a whole number~

Question 40

Calculate the kinetic energy of an ejected electron knowing the frequency and work function

Answer 40

KE = hv - ¤ h = 6.6626×10^-34J×s v = frequency ¤ = work function