Friday, October 13, 2006
Honors Test Diatribe
Since we didn't have time to discuss the exam today, here's some of what needs to be said:
As I graded the Honors Atomic Concepts I Exam, I could plainly see that the majority of you had never been held accountable for following directions. The one in five students who scored in the high 90s applied the information exactly as we had done in class. Those students also explicitly followed the test instructions.
In class, without exception, I modeled every atom-mole-mass problem with proper units, cancellations, and notation. I repeatedly warned that units were required for EVERY calculation on EVERY exam in this class. I explained that a number without a unit is NOT a measurement and is therefore meaningless in most calculations involving measured quantities. I even said DURING THE EXAM that the numbers used should match the decimal places from the data in the question. The next test will be much more challenging because most of the questions require explicit and detailed explanations; also, significant figures will matter in your calculations, now. On future tests, take heed of my advice or the poor grades will continue.
I have stated since day ONE that there are NO makeup tests and NO extra credit in this course. That means you should do your utmost to prepare BEFORE each test or quiz because these assessments are the reflections of your knowledge. One should NEVER expect extra credit in ANY course unless one first earns the BASIC credit from the tests in the course.
I am NOT saying that chemistry is easy, but an Honors student should prepare until the material is bulletproof and understood backwards and forwards before a test. Perhaps some of you do not have or will not make available the time required to achieve such understanding. I stayed after school every day and I would occasionally have one or two students come in with a couple of questions. I was in at 7:30 on days 1 and 4 and nobody showed even after all the buses were in.
Here are some of the major wanton flaws that were handed in on this exam; these errors should not be made by a true "Honors" student:
Ignorance of the meaning of mass number (recall that I said over 40 times that a mass number is really the proton plus neutron number)- you simply had to ADD the number of protons and neutrons instead of wasting your time looking up ATOMIC MASS (which clearly is a different phrase than "mass number") in the periodic table. Had you done the practice files and hw, you would repeatedly have seen the complete difference between atomic mass and mass number.
The chart on question 2 EXPLICITLY AND PLAINLY stated that the symbol had to include any NET CHARGE and the MASS NUMBER of the isotopes (as based on the sum of the protons and neutrons in that row of the table). MOST of you put NOTHING for either charge or mass and some of you put the wrong symbol which was PLAINLY on the Periodic Table that has a legend indicating the atomic number for each element.
There was no understanding of the difference between the law of constant composition (by mass) and the law of multiple proportions. See the notes: these laws are very different- one law requires one compound, the other law requires at least two compounds.
In the math calculation section, if units were even used, many times they were used inconsistently or illogically. Any time that units do not match perfectly, numerator with numerator, denominator with denominator, your answer will be WRONG. I stated that repeatedly and was ignored by many. Many people had impossible answers such as 8.398 atoms of Ne. Atoms are INDIVISIBLE! You can have 8 atoms or 9 atoms but NEVER 8.398 atoms.
Do not shorten or abbreviate the data from a question, EVER. If the question says that you have 24.00 g of Carbon, do NOT shorten that to 24 g or, even worse, to just 24. 24 is a TV show!
The bottom line is that many of you have no idea how much you need to practice to succeed in this course. NONE of you are starting on an even playing field. Some have to compensate a lot more than others in order to know the material in this course. Knowing chemistry requires much more than mere memorization although memorization is absolutely a basic essential; you have to know the HOW and WHY even for setting up a calculation.
Start preparing for the next test and come to extra help PREPARED with questions.
As I graded the Honors Atomic Concepts I Exam, I could plainly see that the majority of you had never been held accountable for following directions. The one in five students who scored in the high 90s applied the information exactly as we had done in class. Those students also explicitly followed the test instructions.
In class, without exception, I modeled every atom-mole-mass problem with proper units, cancellations, and notation. I repeatedly warned that units were required for EVERY calculation on EVERY exam in this class. I explained that a number without a unit is NOT a measurement and is therefore meaningless in most calculations involving measured quantities. I even said DURING THE EXAM that the numbers used should match the decimal places from the data in the question. The next test will be much more challenging because most of the questions require explicit and detailed explanations; also, significant figures will matter in your calculations, now. On future tests, take heed of my advice or the poor grades will continue.
I have stated since day ONE that there are NO makeup tests and NO extra credit in this course. That means you should do your utmost to prepare BEFORE each test or quiz because these assessments are the reflections of your knowledge. One should NEVER expect extra credit in ANY course unless one first earns the BASIC credit from the tests in the course.
I am NOT saying that chemistry is easy, but an Honors student should prepare until the material is bulletproof and understood backwards and forwards before a test. Perhaps some of you do not have or will not make available the time required to achieve such understanding. I stayed after school every day and I would occasionally have one or two students come in with a couple of questions. I was in at 7:30 on days 1 and 4 and nobody showed even after all the buses were in.
Here are some of the major wanton flaws that were handed in on this exam; these errors should not be made by a true "Honors" student:
Ignorance of the meaning of mass number (recall that I said over 40 times that a mass number is really the proton plus neutron number)- you simply had to ADD the number of protons and neutrons instead of wasting your time looking up ATOMIC MASS (which clearly is a different phrase than "mass number") in the periodic table. Had you done the practice files and hw, you would repeatedly have seen the complete difference between atomic mass and mass number.
The chart on question 2 EXPLICITLY AND PLAINLY stated that the symbol had to include any NET CHARGE and the MASS NUMBER of the isotopes (as based on the sum of the protons and neutrons in that row of the table). MOST of you put NOTHING for either charge or mass and some of you put the wrong symbol which was PLAINLY on the Periodic Table that has a legend indicating the atomic number for each element.
There was no understanding of the difference between the law of constant composition (by mass) and the law of multiple proportions. See the notes: these laws are very different- one law requires one compound, the other law requires at least two compounds.
In the math calculation section, if units were even used, many times they were used inconsistently or illogically. Any time that units do not match perfectly, numerator with numerator, denominator with denominator, your answer will be WRONG. I stated that repeatedly and was ignored by many. Many people had impossible answers such as 8.398 atoms of Ne. Atoms are INDIVISIBLE! You can have 8 atoms or 9 atoms but NEVER 8.398 atoms.
Do not shorten or abbreviate the data from a question, EVER. If the question says that you have 24.00 g of Carbon, do NOT shorten that to 24 g or, even worse, to just 24. 24 is a TV show!
The bottom line is that many of you have no idea how much you need to practice to succeed in this course. NONE of you are starting on an even playing field. Some have to compensate a lot more than others in order to know the material in this course. Knowing chemistry requires much more than mere memorization although memorization is absolutely a basic essential; you have to know the HOW and WHY even for setting up a calculation.
Start preparing for the next test and come to extra help PREPARED with questions.
# posted by C @ 7:12 PM 
