WEEK SIX

 

Liberato Cardellini

 

This is the last week: we have completed 48 hours of instruction.

 

Monday 10 (1.5 h)

1 hour theory; 0.5 hours solving a couple of problems on ionic equilibrium calculation.  I have collected 5 concept maps.  I have corrected 247 problems finding 121 wrong solutions and results.

 

Thursday 13 (3 h)

We solve more problems on ionic equilibrium calculation and we start the titration of HCl with NaOH.  As homework I suggested to continue the calculations and to draw the titration curve.  1 hour was devoted to see and discuss the results of the written examination.  Three students complained about the mark.  In the message I attached a logic procedure for solving ionic equilibrium calculations.  I sent them also this problem: Calculate the pH of a solution of acetic acid 1.00 x 107 M. Ka = 1.753 x 105 M.  It is only a didactic problem, but if students are able to solve this problem with a logic reasoning, this means that they have learned how to use the method of calculation.

I have collected 10 concept maps.  I have corrected 205 problems finding 5 wrong solutions and results.

 

Friday 14 (4 h)

I finished the explain the last concepts and we solved problems for about 2.5 hours.  I have collected 6 concept maps and I have corrected 105 problems.

 

Here is the problem that my students find difficult: 10.00 mL of a solution of H2SO4 that is 2.485% by weight (density 1.015 g/mL) are diluted to 100.0 mL. How many milliliters of NaOH 1.000 x 102 M are necessary to neutralize 20.00 mL of the H2SO4 solution prepared before?

 

This week I have received other original and creative solutions of the problem 5 (week two): the total number is 11.  I am a bit disappointed because other students are very close to reach the goal.  I received 15 messages, two about density, some about the mark received in the Saturday 8th written examination and few asking for a friendly talk about motivations.

 

A window in my office.

Pile of solutions: 3,549 from the fifth week + 557 = 4,106.

 

Comments

In this course I have received less concept maps and creative solutions compared with previous courses.  One explanation can be that my two colleagues this year started with the written examinations, so there is competition between teachers in obtaining the efforts and the attention of students.  This, I think, it is good for the learning process.