Principles of Chemistry I - Final Exam Study Guide

C

Which is a heterogeneous mixture?

B

Which is a homogeneous mixture?

D

Which is a pure substance?

True

T or F: Every substance has at least 1 differentiating characteristic.

A, C

Which 2 of these are requirements for differentiating characteristics?

A) Are intensive
B) Are extensive
C) Are unique for each substance
D) Change depending on environment (temp, pressure, etc)

Boiling point, melting point, density, melting point

List some good differentiating characteristics

Mass, volume, concentration, temperature, pressure, solubility

List some bad differentiating characteristics

A

Is it intensive or extensive? -- Chemical reactions

A) Intensive
B) Extensive

A

Is it intensive or extensive? -- Temperature

A) Intensive
B) Extensive

A

Is it intensive or extensive? -- Density

A) Intensive
B) Extensive

B

Is it intensive or extensive? -- Volume

A) Intensive
B) Extensive

The water comes out of the gas phase and freezes, and the oxygen becomes a liquid, so the balloon shrinks

If you put a balloon in liquid nitrogen, what happens to the balloon?

C

During a phase change, energy is ____________ stored/released by the system.

A) Sometimes
B) Never
C) Always

D

The amount of energy exchanged per unit mass of a substance is a ______________.

A) Phase change
B) Triple point
C) Vaporization
D) Differentiating Characteristic

D

Where are the phase changes occurring?

A) Between A&B, and D&E
B) Between A&B, and C&D
C) Between C&D, and E&F
D) Between B&C, and D&E

D

Where is PE increasing a lot?
A) Between A&B, and D&E
B) Between A&B, and C&D
C) Between C&D, and E&F
D) Between B&C, and D&E

B

Where is KE increasing a lot?
A) Between A&B, and D&E
B) Between A&B, and C&D
C) Between C&D, and E&F
D) Between B&C, and D&E

C

Phase stability relies on...

A) The number of molecules
B) Potential energy
C) Pressure & Temperature
D) Pressure only

A glass of water sitting out for a week and "losing" water

What is an example of a liquid that evaporates (to a certain extent) at any temp?

Vapor pressure, atmospheric pressure

Boiling point occurs when ________ equals ________.

Liquid

On a vapor pressure graph, the left side of one of these lines represents what phase?

Ether

Which of these is most volatile?

Filtration

A separating method based on the mechanical separation of substances in the solid-state from substances in a fluid phase (liquid or gas) by using a physical barrier which only the fluid can pass.

Distillation

This technique is used to separate substances in a liquid mixture taking advantage of differences in the boiling points of the various components. It involves a phase change from liquid to gas and the reconversion of the separated substances to the liquid phase.

Crystillation

A separation method that includes changing the temperature or the concentration of the components in a fluid (liquid or gas) mixture, or by adding other substances to include a solid-state.

Pressure

In the ideal gas law, changing mass changes speed, but does not change___________.

Speed

In the ideal gas law, changing temperature changes pressure and ________.

False

T or F: The movement of gas particles in the ideal gas law is uniform and predictable.

Area

Pressure = Force/?

Temperature

A measure of the average KE per particle.

8 J

What is the average KE for a 1kg particle moving at 4 m/s?

KE = (1/2) * m * v^2

Mass

At the same temperature, the speed of different particles will depend on the __________.

Looking at the substance with the highest fraction of particles moving the slowest (least velocity)

In a "% of particles v velocity" graph, the substance with the HIGHEST mass can be found by....

Looking at the substance with the highest fraction of particles moving the fastest (highest velocity)

In a "% of particles v velocity" graph for molecules with different masses, the substance with the LOWEST mass can be found by....

Higher temperature

In a "% of particles v velocity" graph for molecules with different temperatures, the substance with the higher distribution of velocities (aka a "less steep" curve) might have a...

Looking at the substance with the highest fraction of particles moving the fastest (highest velocity).

In a "% of particles v velocity" graph for molecules with different temperatures, the substance with the HIGHEST temperature can be found by....

True

T or F: In a "% of particles v velocity" graph, you shouldn't look at the one with the highest mountain, you should look at the one that has the peak at the highest velocity (when looking for highest temperature or smallest mass)

True

T or F: Substances at the same temperature will have the same KE, regardless of mass.

Pressure, Temperature

What graph is this?

Pressure, Volume

What graph is this?

False

T or F: The average KE of a substance changes during a phase change.

True

T or F: Ionic compounds are not molecules.

Moles

For gases of equal temperature (𝑇),(T), pressure (𝑃),(P), and volume (𝑉),(V), the number of _________ of the gases is equal as well.

D

Gases that represent the ideal gas law are at a high ________ and low __________.

A) Temperature, Mass
B) Pressure, Temperature
C) Number of moles, Volume
D) Temperature, Pressure

A

Use Kb when your amount of substance is given in...

A) Molecules
B) Moles
C) Neither

B

Use R when your amount of substance is given in...

A) Molecules
B) Moles
C) Neither

B

If you raise temperature and the strength of IMFs, what happens to the pressure?

A) No change
B) Increase
C) Decrease

Distance

The strength of intermolecular forces depends on the ____________ between particles.

A

At a single temperature, the substance with the _________ vapor pressure has the highest IMFs.

A) Highest
B) Lowest
C) Neither

D

Phase changes depend on how _________ and ________ are distributed

A) pressure, temperature
B) mass, IMFs
C) volume, temperature
D) energy, matter

Distance, strength

PE depends on the _________ and ___________ of interactions between particles.

Lower PE

For ATTRACTION, closer molecules means....

Higher PE

For REPULSION, closer molecules means....

C

During a phase change, all energy is invested or lost in the form of ___________.

A) Heat
B) KE
C) PE
D) None of the above

True

T or F: The size of the particles matters when considering the PE needed to separate two atoms.

A

When turning a liquid into a gas, we must _________ PE in order to separate the two atoms.

A) Add
B) Subtract
C) Do nothing to

PE & # Configurations

When a system can adopt different states, the one it picks depends on...

B

A system wants to be in a place with the _________ PE and _________ # of configurations


A) Highest, highest
B) Lowest, highest
C) Highest, Lowest
D) Lowest, Lowest

Energetic; configuration

In PEC diagrams, a substance is looking for __________ and _________ stability

Higher

Lower pressures favor states with a ___________ # of configurations.

The composition of the structure of the particles

What is the key differentiating characteristic between substances?

True

T or F: If T, V, and P is the same for 3 gases, the number of mols must be the same for all of them.

A

Higher temps prefer a ________ PE.

A) Higher
B) Lower

1000 L

1 m^3

False

T or F: Most space in the atom is taken up by the nucleus.

True

T or F: Most space in the atom is taken up by the electron cloud.

True

T or F: Most of the mass of the atom comes from the nucleus.

False

T or F: Most of the mass of the atom comes from the electron cloud.

Atomic #

This number refers to the number of protons in the nucleus, but also refers to the number of electrons of the atom if it's in a neutral state.

B

In a neutral atom, __________ = ___________.

A) Protons, neutrons
B) Protons, electrons
C) Neutrons, electrons
D) None of the above

A

The mass of an atom can be determined by adding the number of __________ and ___________.

A) Protons, neutrons
B) Protons, electrons
C) Neutrons, electrons
D) None of the above

True

T or F: Protons and neutrons have about the same mass.

True

T or F: Atoms that are isotopes have the same number of protons, but a different number of neutrons.

Top left: mass, Bottom left: atomic number, Center: symbol

How do you write the atomic symbol of an element?

D

Average atomic mass (mass of an element on the PT) is equal to the...

A) Protons + neutrons of every isotope
B) Number of electrons
C) Percent abundance only
D) Mass times relative abundance

A

In a mass spectrometry graph, all fragments are __________ charged.

A) Positively
B) Negatively
C) Neutral

Particle Composition

Type and number of atoms of each type per particle.

1. Set the percent abundance to grams (ex: 92% becomes 92 grams)
2. Divide each by molar mass
3. Divide the mols by the smallest mass
4. Multiply to whole number if needed

Steps for Finding the Empirical Formula

Divide the given mass of the substance by the mass of the empirical formula, and then multiply that number into the empirical formula

How do you convert the empirical formula to the molecular formula?

X4Y6

A substance is 50 amu. If the empirical formula of this substance is X2Y3, and the mass of X2Y3 is 25 amu, what is the molecular formula of this substance?

C

If you're trying to find the molecular formula of a mass spec, the mass of the substance is the peak on the farthest...

A) Left
B) Center
C) Right
D) None of the above

Electromagnetic radiation

Energy travelling through space as waves formed by oscillating electric and magnetic fields

A

The period of a wave, inverse to frequency, and denoted by ƛ

A) Wavelength
B) Frequency
C) Wavenumber

B

The number of waves per unit time, inverse to wavelength, and denoted by v

A) Wavelength
B) Frequency
C) Wavenumber

Wavelength x frequency

Speed of light = ________ x _____________

C

In absorption spectroscopy, the color that is released is the wavelength with the ___________ absorption.

A) Highest
B) Medium
C) Lowest

C

Absorption is highest when transmittance is ___________.

A) Highest
B) Medium
C) Lowest

A

In an emission spectrum, more lines of emission corresponds to a _____________ molar mass.

A) Higher
B) Medium
C) Lower

Excited State

Any state above ground state for an atom.

Ground state

The lowest energy state of an atom

A

Absorption occurs when the energy is __________.

A) Increasing
B) Decreasing
C) Remaining the same

B

Emmission occurs when the energy is __________.

A) Increasing
B) Decreasing
C) Remaining the same

A

Frequency is __________ as bond strength is increasing.

A) Increasing
B) Decreasing
C) Remaining the same

B

Frequency is __________ as mass is increasing.

A) Increasing
B) Decreasing
C) Remaining the same

B

Total energy is __________ during a bond formation.

A) Increasing
B) Decreasing
C) Remaining the same

Plank's constant x frequency

Energy = ________ * __________ (use v)

Plank's constant x (speed of light/wavelength)

Energy = ________ * __________ (use ƛ)

J/photon

The equation E = hc/ƛ gives you an answer with what unit?

Multiply by Avogadro's number

If you have energy in units of J/photon, how do you find the energy of 1 mol?

C

Microwaves are usually associated with a change in _________________.

A) excitation/bond breaking state
B) vibrational state
C) rotational state