Name That Unit!
Calculate the pH of a 0.10 M solution of a weak acid HA that has a Ka value of 1.0 x 10-5.
Unit 8 - Acids and Bases
A certain first-order radioactive decay process has a rate constant (k) of 0.0023 min-1. Calculate the half-life (t1/2) of the substance.
t1/2 = 0.063/k
A certain reaction is found to be exothermic and results in an increase in disorder of the system. What are the signs for enthalpy, entropy, and Gibbs free energy (delta G)?
Enthalpy = negative
Entropy = positive
Gibbs free energy = negative
Why is the atomic radius of calcium significantly larger than the atomic radius of magnesium?
Is the difference attributed to the atom's nuclear charge or the number of electron shells?
Electron shells
How many college level degrees does Mr. Marchione have?
Two (undergrad from MSU and a masters from CMU)
Ethanol (C2H5OH) has a much higher boiling point than dimethyl ether (CH3OCH3), even though they have the same molecular formula. Explain the reasoning behind this phenomenon.
Unit 3 - Intermolecular Forces and Properties
How much heat is required to raise the temperature of 25 g of iron from 20 oC to 50 oC?
A reaction changes state from a gas to a solid through an endothermic process. Is this a thermodynamically favorable reaction in terms of Gibbs free energy (delta G)?
No
Why is the atomic radius of oxygen smaller than the atomic radius of nitrogen?
Is the difference attributed to the atom's nuclear charge or the number of electron shells?
What is Marchione's least favorite color?
A 50.0 g sample of water at 25.0 oC absorbs 2,090 J of heat. Calculate the final temperature of the water.
Unit 6 - Thermodynamics
A galvanic cell has a standard cell potential + 1.10V and involves the transfer of 2 moles of electrons. Calculate the standard Gibbs free energy change for the reaction in joules.
Delta G = - nFEo
The freezing of liquid water is an exothermic process that results in a decrease in entropy. A student claims this is a thermodynamically favorable reaction driven by entropy. Do you agree?
No or Disagree
Would it require less energy to remove lithium's or potassium's outermost valence electron?
Potassium
What is Mr. Marchione's wife's name?
Sarah
For a process where enthalpy is positive and entropy is positive, under what conditions (high or low) will the reaction be thermodynamically favored?
Unit 9 - Applications of Thermodynamics
A buffer solution contains 0.50 M ethanoic acid and 0.50 M sodium ethanoate. If the pKa of ethanoic acid is 4.74, calculate the pH of the buffer.
A reaction is deemed to be thermodynamically unfavorable. To make this reaction more favorable, you could either add a catalyst or change the temperature. Which is the correct choice?
Change the temperature
Would it be easier to remove sodium's or magnesium's 2nd valence electron?
What high school did Mr. Marchione graduate from?
Anchor Bay
For a certain reaction, a plot of ln(A) versus time yields a straight line with a negative slope. What is the order of the reaction with respect to reactant A, and what does the slope of the line represent?
Unit 5 - Kinetics
A 0.20 M solution of KMnO4 has an absorbance of 0.85. If the molar absorptivity of the solution is 2.125 L/(mol x cm), what is the width (path length) of the cuvette being used?
A = ebc
Cu2S --> 2 Cu + S Delta G = +86.2 kJ/mol
S + O2 --> SO2 Delta G = -300.1 kJ/mol
Yes
Delta G = -213.9 kJ/mol
What would the charge of an ion be with the following ionization energies? What compound would it make with Oxygen? (Use X as the unknown atom in your chemical formula)
1st = 578 kJ/mol
2nd = 1,817 kJ/mol
3rd = 2,745 kJ/mol
4th = 11,577 kJ/mol
5th = 12, 889 kJ/mol
+3
X2O3
How many different pairs of work shoes does Mr. Marchione own?
Three