Chemistry Midterm

Question 1

Empirical Formula

Answer 1

(% g E)(1 mol E/atomic weight E) = mol E

Biggest Decimal/Smallest Decimal = Whole Number

Question 2

Molecular Formula

Answer 2

(Molecular Weight)/(Empirical Formula Weight) = Whole Number Multiples

Question 3

Limiting Reactants

Answer 3

• How many moles of each reactant? (4 mol A, 2 mol B)
• 4 mol A to find mol of B
• Less than 2? Limiting reactant is A

Question 4

Percent Yield

Answer 4

Actual yield/Theoretical yield * 100%

Question 5

Acid

Answer 5

When ionized, produces H+ ions

Question 6

Bases

Answer 6

Accept H+ ions. Form OH- when dissolved in water.

Question 7

Neutralization Reaction

Answer 7

Acid + Base (metal hydroxide) = H2O and Salt

Question 8

Oxidation-Reduction Reaction

Answer 8

One reactant gives another its electrons

Question 9

Oxidized

Answer 9

Loses electrons (more + charged)

Question 10

Reduced

Answer 10

Gains electrons (more - charged)

Question 11

Oxidizing Agent

Answer 11

Gets reduced (vice versa)

Question 12

Oxidation Numbers

Answer 12

1. Elemental Form = 0
2. Monatomic Ions = Charge
3. Nonmetals = - sometimes +

Question 13

Displacement Reaction

Answer 13

Metal + Acid or Metal Salt
A + BX -> AX + B

Question 14

Molarity

Answer 14

Moles solute/Volume of solution

Question 15

Dilution

Answer 15

M1V1 = M2V2

Question 16

L to mL

Answer 16

1 L = 1000 mL

Question 17

Endothermic Processes…

Answer 17

Absorb heat

(Ex. Ice melting or water boiling)

Question 18

First Law of Thermodynamics

Answer 18

Energy can be converted but never created or destroyed

Question 19

Internal Energy

Answer 19

E(final) - E(initial)

Question 20

State Function

Answer 20

Does not depend on the path (flow of energy). Describes its current state.

Question 21

Periodic Trends:

Answer 21

Down:
- Atomic size increases
- Energy Levels increase (more shielding)
- Ionization Energy decreases

Across:
- Zeff increases
- More electrons
- Atomic size decreases
- Ionization energy increases

Question 22

List some state functions and not state functions

Answer 22

State Function:
Internal Energy
Enthalpy (extensive property)

NOT state function:
Work
Heat

Question 23

Avogadro’s Number

Answer 23

6.0221*10^23

Question 24

L/mol at stp

Answer 24

22.4 L/mol

Question 25

Halogen States of Matter

Answer 25

Fluorine - Gas Chlorine - Gas Bromine - Liquid Iodine - Solid Astatine - Solid

Question 26

Number of Molecules

Answer 26

Mass/molecular weight * avogadro’s number

Question 27

Molar Mass

Answer 27

Mass/mol

Question 28

Standard State Conditions

Answer 28

1 atm and 298 K

Question 29

Enthalpy

Answer 29

H = Internal E + PV

Question 30

Pressure-Volume Work

Answer 30

w = -P delta V

Question 31

Pressure (atm)

Answer 31

1 L-atm = 101.3 J

Question 32

Closed vs Isolated system

Answer 32

Closed: matter cannot enter or leave Isolated Matter, Heat and work cannot enter or leave

Question 33

Ionization Energy

Answer 33

Amount of energy to remove an electron from an ion or gaseous atom

Question 34

Acid naming

Answer 34

If no oxygen: Hydro-anion-ic If yes oxygen: Anion-ic (for ate) anion-ous (for ite)

Question 35

Hrxn = Hf when

Answer 35

All reactants are not compounds All reatants are in their standard state

Question 36

Hrxn =

Answer 36

delta H1 + delta H2 + delta H3 Sum of H products - sum of H reactants

Question 37

Bond Enthalpies

Answer 37

Enthalpies of bonds broken - enthalpies of bonds formed

Question 38

Bond Enthalpies are...

Answer 38

Always positive

Question 39

1 Cal =

Answer 39

4.184 J

Question 40

Units for Specific Heat Capacity

Answer 40

J/g* degrees c

Question 41

Units for heat capacity

Answer 41

J/degrees C