ACS Exam Review
Topic 1: Naming Compounds
Name the following compounds:
Na3PO4Sodium Phoshpate
FeCl2Iron (II) Chloride
Write the molecule in symbol form:
Beryllium NitrideBe3N2
DinitrogenTetraoxideN2O4
Topic 2: Limiting Reactant
If 45.0 g of H2S and 50.0 g of O2 were allowed to react in the equation, how many grams of S8 could be produced? If in the lab we produced 90% yield, how much S8 would we have?
8 H2S (g) + 4 O2 (g) S8 (l) + 8 H2O (g)
42.3 g S8 with 45 g of H2S as limiting reactant, 38.1 g with 90% yield
Topic 3: Energetics
The specific heat of aluminum is 0.90 J/g-°C. When you add 250 J of heat to 30 g of aluminum originally at room temperature (25°C), what will the final temperature be?
Tf= 34 C
Find the ΔH for the reaction
2 N2(g) + 5 O2(g) 2 N2O5(g)
Using these reactions:
2 H2(g) + O2(g) 2 H2O(l) (Ho/kJ = -571.6) reverse
N2O5(g) + H2O(l) 2 HNO3(l)(Ho/kJ = -73.7) reverse and x2
N2(g) + 3 O2(g) + H2(g) 2 HNO3(l)(Ho/kJ = -348.2) x 2
Overall= 22.6
Topic 4: Electronic Structure
What is the frequency of a radiation with a wavelength of 567 nm?
5.29 x 1014 s-1
What is the energy of a photon of electromagnetic radiation whose wavelength is 233 nm?
E= 8.53 x 10-10 J
Topic 5: Quantum Numbers
Give the following quantum numbers possible for l, ml, and ms when n=2.
n / 2l / 0 / 1
ml / 0 / -1 / 0 / 1
ms / +.5 / -.5 / +.5 / -.5 / +.5 / -.5 / +.5 / -.5
Give the electron configuration of Mn.
[Ar]4s23d5
Topic 6: Lewis Structures
Draw the Lewis structures of the following compounds:
NH3PBr5SO3
You can google these to see if you are correct
Topic 7: Gas Law
How many grams of Helium will produce a pressure of 1.2 atm in a volume of 350 mL at 300 K?
0.068 g He
Topic 8: Kinetics
- For the reaction A + B AB, the following data was obtained
Trial / [A] (M) / [B] (M) / Initial Rate (M/s)
1 / 0.720 / 0.180 / 0.470
2 / 0.720 / 0.720 / 1.880
3 / 0.360 / 0.180 / 0.117
a)Determine the order for each reactant
B is 1st order
A is 2nd order
b)What is the overall order of reaction?
3rd order
c)Write the rate expression for the reaction
Rate= k[A]2[B]
d)What is the value of the rate constant, k?
K= 5.04 x 10-2 M-2 s-1
Given the following graphs, what is the order of the reaction?
1st order because ln(A) vs. Time is straight
If the equation of the linear trendline is y= -0.0002 + 6.2251, what is the value of the rate constant?
Slope= -k
K= 0.0002
What is the half-life of the reaction?
T1/2= 0.693/K
T1/2= 3465 sec
What will [A] be at t= 10,000 seconds if the original concentration was 500 M?
A= 67.7 M
The reaction below is showing ______decay. Fill in the missing element with the atomic and mass number.
Topic 9: Acids/Bases/Buffers
Name the 7 Strong Acids
What is the pH of a solution containing 0.02 M NaOH?
pH= 12.3
Find the pH of a solution containing 0.21 M Nitrous Acid (HNO2). The Ka for nitrous acid is 4.0 x 10-4.
pH= 2.04
What would the pH be if you added 0.23 mol of NaNO2 and the solution had a total volume of 1 L.
Use Henderson hasselbach
pH= 3.44
Topic 10: Thermodynamics
Calculate the standard enthalpy, entropy, and free energy of the following reaction using the formation values found in the table.
C2H4 (g) + 3 O2 (g) 2 CO2 (g)+ 2 H2O (g)
Substance / ΔG°f (kJ/mol) / ΔS°f (J/mol*K) / ΔH°f (kJ/mol)C2H4 (g) / 68.4 / 219.5 / 52.3
O2 (g) / 0 / 205.0 / 0
CO2 (g) / -394.3 / 213.7 / -393.5
H2O (g) / -228.6 / 69.9 / -241.8
G= -1314.2 kJ
S= -267.3 J/K
H= -1322.9 kJ
If a reaction has a ΔH= 32 kJ and ΔS= 60 J, what will the ΔG be at 200 K? Is the reaction spontaneous?
-8800 J, spontaneous
Topic 11: Electrochemistry
Balance the following equation
H3AsO4(aq) + Zn(s) →AsH3(g) + Zn2+(aq) (acidic)
8H+ + H2AsO4 + 4Zn AsH3 + 4 Zn2+ + 4 H2O
Using the half reactions, calculate the free energy of the reaction.
Al3+(aq) + 3e- Al (s) E°= -1.66 V
Au3+ + 3e-(aq) Au (s) E°= 1.50 V
E= 3.16
G= -nFE
= (-3) (96485) (3.16)= -915000 J