Exam 2, CH 4, Molarity, Redox, CH 5, Theromodynamics

Molarity Solution (equation) =

(moles solute) / (L solution) or (moles of solution) / (1000 mL solution)

Dilution Equation:

Mc x Vc = Md x Vd

- where Mc and Md are the molarity of the concentrated solution, and Vc and Vd are the volumes of the two solutions.

strong acids:

• Hydrochloric: (HCl)

• Hydrobromic: (HBr)

• Hydroiodic: (HI)

• Chloric: (HClO3)

• Perchloric: (HClO4)

• Nitric: (HNO3)

• Sulfuric: (H2SO4)

strong bases:

• Group 1A metal hydroxides

• Heavy group 2A metal hydroxides (Ca(OH)2 and down).

Assigning Oxidation States:

1). The oxidation state of an atom in a free, uncombined element = 0

2). The sum of oxidation numbers of all atoms must equal the total charge [neutral=0,

ion=charge]

3). In compounds, Group IA = +1(not including H), IIA = +2, B and Al = +3, F = -1

4). In compounds, H = +1

5). In compounds, O = -2

6). In their binary compounds with metals, VIIA=-1, VIA=-2, VA=-3

- Highest order rule takes precedence -

Balancing Redox Reactions:

[Note – this method leaves spectator ions out.]

1) Divide the reaction into half reactions

2) Balance all atoms in half reactions except “H” and “O”

3) Balance “O” by adding H2O

4) Balance “H” by adding H+

5) Balance each half reaction electronically by adding e-

6) Multiply each half reaction by an integer to get electrons in each half reaction to

be the same

7) Acidic solutions: Combine the two half reactions, canceling anything that is the

same on both sides of the arrow

Basic solutions: Add OH- to both sides of the reaction to balance the H+

. H+ +

OH- will yield H2O, then add the two half reactions

∆E = ?

∆E =
E_final - E_initial
E_products - E_reactants

∆_Esystem = ?

∆_{Esystem =} w + q

w = ?

w = -P∆V,
-P = Pressure, typically atmosphereic pressure
∆V = Change in volume, typically volume occupied by gasses produced in a chemical reaction.

Enthlapy is…

• ∆H = ∆E + P∆V

• … the sum of all the heat and all the work that occur during a reaction

• ∆H = change in enthalpy

• enthalpy requires that workbe P∆V work at constant pressure.

• If no work is done, then the ∆E for the reaction is equal to the ∆H.

Q = ?

Q = C_sm∆T

q_rxn = ?

q_rxn = -C_cal∆T

∆H°_rxn = ?

∆H°_rxn = Σn∆H°_f(products) - Σm∆H°_f(reactants)