thee shalt not forget

Question 1

What is the difference between separating compounds and mixtures?

Answer 1

Compounds can be separated into elements by chemical changes, and mixtures can be separated by physical changes.

Question 2

How does filtering separate mixtures?

Answer 2

Filtering separates mixtures based on differences in particle size.

Question 3

What is distillation used for?

Answer 3

Distillation separates mixtures based on differences in boiling point.

Question 4

What principle does chromatography rely on?

Answer 4

Chromatography separates mixtures based on differences in polarity.

Question 5

In paper chromatography, which component moves up the farthest?

Answer 5

The component that is most similar in polarity to the ‘mobile phase’.

Question 6

What is the law of conservation of mass?

Answer 6

Mass is conserved during chemical and physical changes.

Question 7

How can you estimate the volume of a liquid in a container?

Answer 7

Read in between the graduated markings for one more significant figure.

Question 8

What is the ranking of measuring devices from least precise to most precise?

Answer 8

Beaker, graduated cylinder, volumetric flasks, burette.

Question 9

What is the formula for density?

Answer 9

Density = mass/volume.

Question 10

Does the % composition by mass of a pure compound change?

Answer 10

No, it does not change.

Question 11

What happens to an electron in a higher energy level?

Answer 11

It is farther away from the nucleus and has less Coulombic attraction, making it easier to remove.

Question 12

What happens to ionization energy as you move across a row on the periodic table?

Answer 12

Ionization energy increases due to increased Zeff, which attracts valence electrons more strongly.

Question 13

What does a PES graph indicate about electron sublevels?

Answer 13

The higher the peak, the more electrons there are in that sublevel.

Question 14

How do you write the electron configuration for a cation?

Answer 14

Remove valence electrons first, then d-orbital electrons if necessary.

Question 15

What are isotopes?

Answer 15

Isotopes of an element have the same number of protons but different numbers of neutrons.

Question 16

What do mass spectroscopy graphs measure?

Answer 16

They measure atomic masses of isotopes.

Question 17

What do elements in the same group have in common?

Answer 17

They have similar chemical and physical properties.

Question 18

How do cations and anions compare in size to their neutral atoms?

Answer 18

Cations are smaller and anions are larger than their atoms.

Question 19

What type of bond is formed between two nonmetals?

Answer 19

Covalent bonds.

Question 20

How are ionic bonds formed?

Answer 20

When a metal transfers electrons to a nonmetal, and the opposite charges attract.

Question 21

What do combustion reactions produce?

Answer 21

CO2 and H2O.

Question 22

What is the empirical formula rhyme?

Answer 22

% to mass, mass to mole, divide by small, times until whole.

Question 23

What is the relationship between the molecular formula and the empirical formula?

Answer 23

The molecular formula is a whole number multiple of the empirical formula ratio.

Question 24

How do you calculate % yield?

Answer 24

% yield = (experimental/theoretical).

Question 25

What determines the amount of product in a reaction?

Answer 25

The limiting reactant.

Question 26

Why are gas mixtures homogeneous?

Answer 26

Due to the constant random motion of the particles.

Question 27

What causes gas pressure?

Answer 27

Collisions of particles with the walls of the container.

Question 28

What is the relationship between pressure and volume?

Answer 28

P and V are inversely related.

Question 29

What is the gas law equation?

Answer 29

PV=nRT.

Question 30

What is the volume of one mole of an ideal gas at STP?

Answer 30

22.4 Liters.

Question 31

What is the relationship between gas pressure and the number of moles?

Answer 31

They are directly related.

Question 32

What is the formula for molar mass in terms of gas properties?

Answer 32

Molar Mass = dRT/P.

Question 33

What does temperature represent in terms of gas behavior?

Answer 33

Average kinetic energy.

Question 34

What is the relationship when collecting gas by water displacement?

Answer 34

Ptotal = Pdry gas + Pwater vapor.

Question 35

When do real gases behave most like ideal gases?

Answer 35

At high temperature and low pressure.

Question 36

What characterizes exothermic reactions?

Answer 36

(−) ΔH; heat is a product.

Question 37

What does ΔHrxn represent?

Answer 37

Bonds broken − Bonds formed.

Question 38

What happens to ΔH when a reaction is reversed?

Answer 38

The sign for ΔH changes.

Question 39

What is the bond angle for a molecule with 4 domains?

Answer 39

109.5°.

Question 40

What is the hybridization for 3 domains?

Answer 40

sp2.

Question 41

What is the significance of lattice energy?

Answer 41

It is the energy to break an ionic bond in a compound.

Question 42

What is the difference between interstitial and substitutional alloys?

Answer 42

Interstitial alloys have smaller atoms fitting between larger atoms, while substitutional alloys have similar-sized atoms replacing each other.

Question 43

What is required for a reaction to occur?

Answer 43

Particles must collide at the correct orientation and with a minimum energy (activation energy).

Question 44

How can you speed up a reaction?

Answer 44

Add a catalyst, increase reactant concentration, increase surface area, increase pressure of gases, increase temperature.

Question 45

What does the half-life of a 1st order process depend on?

Answer 45

It is constant regardless of the initial concentration.

Question 46

What does a larger activation energy indicate about a reaction's speed?

Answer 46

The slower the reaction.

Question 47

What is the equilibrium constant expression for a reaction?

Answer 47

Keq = [products]x/[reactants]y.

Question 48

What does a large Keq value indicate?

Answer 48

There are more products at equilibrium.

Question 49

What is Le Chatelier's Principle?

Answer 49

If Q > Keq, the reaction shifts to the left towards the reactants.

Question 50

What is the pH range for acids and bases?

Answer 50

Acids are less than 7; bases are greater than 7.

Question 51

What do strong acids do?

Answer 51

They donate [H+].

Question 52

What is the relationship between acid strength and its conjugate base?

Answer 52

The stronger the acid, the weaker its conjugate base.

Question 53

What does a larger Ka value imply?

Answer 53

A stronger acid.

Question 54

What happens to % ionization of a weak acid as the acid concentration decreases?

Answer 54

It increases.

Question 55

What characterizes salts containing conjugate bases of weak acids?

Answer 55

They are slightly basic.

Question 56

What is the formula for calculating pH?

Answer 56

pH = −log [H+].

Question 57

What does the shortcut [H+] = Square Root of MaKa apply to?

Answer 57

It applies if 'x' is small compared to Ma.