Unit 1 Loose Ends and Test Review Unit 1 Loose Ends and Test Review

Objective A (remember, the objective refer to the Study Guides) Look at the following numbers. How easy would it be to memorize this list and regenerate it in a week or so on a quiz? Look at the following numbers. How easy would it be to memorize this list and regenerate it in a week or so on a quiz? 1, 3, 5, 11, 21, 43, 85, 171, 341, 683, 1365, 2731, 5461, 10923, , 3, 5, 11, 21, 43, 85, 171, 341, 683, 1365, 2731, 5461, 10923, Pretty hard? Pretty Easy? Why? Pretty hard? Pretty Easy? Why? Easy huh? OK, what’s the next number in the sequence? How about the next 5 numbers? Easy huh? OK, what’s the next number in the sequence? How about the next 5 numbers?

1, 3, 5, 11, 21, 43, 85, 171, 341, 683, 1365, 2731, 5461, 10923, The numbers don’t seem to follow any kind of pattern. The numbers don’t seem to follow any kind of pattern. But, what if you knew a rule? It wouldn’t just be memorization then. But, what if you knew a rule? It wouldn’t just be memorization then. OK, good point! The rule is: OK, good point! The rule is: Start with 1. Start with 1. Double and add 1. Double and add 1. Double and subtract 1. Double and subtract 1. And so on. And so on. You just wish it was that EASY!

Learn HOW to do the problem; don’t just memorize the answer! Doesn’t “knowing the rule” make the list easier to memorize? Doesn’t “knowing the rule” make the list easier to memorize? You don’t have to memorize a bunch of unrelated numbers. You don’t have to memorize a bunch of unrelated numbers. IF YOU KNOW the rule, you can generate the number list on the test easily. Anytime! Anywhere! IF YOU KNOW the rule, you can generate the number list on the test easily. Anytime! Anywhere! Don’t

Can you make sense out of NONSENSE? ForceHourUponNeigh ForceHourUponNeigh KoranForceCisShun KoranForceCisShun HeavenFodderCount HeavenFodderCount YeBratAnent YeBratAnent SagoFarceAnew SagoFarceAnew Figured it out yet? Figured it out yet?

The Gettysburg Address “Four score and seven years ago our fathers brought forth on this continent a new nation, conceived in Liberty, and dedicated to the proposition that all men are created equal.” “Four score and seven years ago our fathers brought forth on this continent a new nation, conceived in Liberty, and dedicated to the proposition that all men are created equal.” Being able to look at something new, and make sense of it is an important skill for the rest of this course. Being able to look at something new, and make sense of it is an important skill for the rest of this course. Yes, Ms Rackley, I know this was Antietam, but it’s a nice picture.

Objective A In Chemistry, when we have numbers, much of the time we do one of three things: In Chemistry, when we have numbers, much of the time we do one of three things: Multiple 2 x 3 Multiple 2 x 3 Divide 2 / 3 Divide 2 / 3 Divide 3 / 2 Divide 3 / 2 If you can figure out which operation to do when, you can actually solve the problem. That’s our goal. If you can figure out which operation to do when, you can actually solve the problem. That’s our goal. What would Bill Nye do? Answer: nothing because he just died.

Units TELL you the right ANSWER! If your units don’t work out right, your answer is wrong. If your units don’t work out right, your answer is wrong. Don’t just ignore wrong units. It is a big clue for you. Don’t just ignore wrong units. It is a big clue for you. LISTEN to the units! LISTEN to the units!

Qualitative and Quantitative Data Qualitative (think quality) Qualitative (think quality) These are observations usually. These are observations usually. It’s blue. It’s hot. It’s cool. It’s smells like rotten eggs. It’s blue. It’s hot. It’s cool. It’s smells like rotten eggs. Remember to look for qualitative date when you do your lab experiments. Remember to look for qualitative date when you do your lab experiments. Quantitative (think quantity or amount) Quantitative (think quantity or amount) These are the numbers you measure. These are the numbers you measure. 5.0 g of baking soda. 2L of diet Coke. 4.5 moles of CO g of baking soda. 2L of diet Coke. 4.5 moles of CO 2. Remember to record quantitative data in your lab notebook when you do experiments too. Remember to record quantitative data in your lab notebook when you do experiments too.

Objective C…Error We will discuss error primarily in our labs. Always include a discussion of any errors that happened in your experiment in your “Analysis of Data” section of your lab report. We will discuss error primarily in our labs. Always include a discussion of any errors that happened in your experiment in your “Analysis of Data” section of your lab report. What kind of errors can you have in your labs? What kind of errors can you have in your labs? Two kinds: Two kinds: Random Random Systematic Systematic

Objective C…Error Random errors are mistakes. You can take care to reduce or eliminate random errors. These usually come from being unprepared (not reading the lab prior to doing it), rushing to get done, and careless errors (like forgetting to do a step). Random errors are mistakes. You can take care to reduce or eliminate random errors. These usually come from being unprepared (not reading the lab prior to doing it), rushing to get done, and careless errors (like forgetting to do a step). Systematic errors are errors that are present in your system. You can’t do anything about these. If your data is precise, but not accurate this might indicate that you had systemic error. Systematic errors are errors that are present in your system. You can’t do anything about these. If your data is precise, but not accurate this might indicate that you had systemic error. Easy Button Error Button

Objective d…Significant Figures When you take measurements in Chemistry class or in lab, you have to worry about how many significant figures (usually abbreviated as sig figs) you have. When you take measurements in Chemistry class or in lab, you have to worry about how many significant figures (usually abbreviated as sig figs) you have. What are sig figs? What are sig figs? All the digits you can read and the first one you can estimate. All the digits you can read and the first one you can estimate. Between 7.1 and 7.2, so record as All 3 digits are significant, because you read the first 2 and estimated the last 1.

Objective d…Significant Figures However, if you didn’t measure it, there are rules for figuring out how many sig figs something has. However, if you didn’t measure it, there are rules for figuring out how many sig figs something has. RULE #1. All non-zero digits are significant. RULE #1. All non-zero digits are significant. So that means that the only thing you have to determine is whether or not the zeros are significant. So that means that the only thing you have to determine is whether or not the zeros are significant. Significant? Maybe or maybe not!

Objective d…Significant Figures Rules are in the study guide. Rules are in the study guide. 2. Zeros between non zero digits are significant. So, has 4 sig figs. 2. Zeros between non zero digits are significant. So, has 4 sig figs. 3. Zeros at the end of a number AND to the right of the decimal point are significant. So, has 4 sig figs. 3. Zeros at the end of a number AND to the right of the decimal point are significant. So, has 4 sig figs. 4. Zeros at the beginning of a number are never significant. So, has 2 sig figs. 4. Zeros at the beginning of a number are never significant. So, has 2 sig figs. 5. Exact measurements or exact quantities have an unlimited amount of sig figs. Example 1 hour = 60 min. “1” and “60” both have an unlimited number of sig figs. 5. Exact measurements or exact quantities have an unlimited amount of sig figs. Example 1 hour = 60 min. “1” and “60” both have an unlimited number of sig figs.

Objective d…Significant Figures Adding/Subtracting Adding/Subtracting Answer cannot have more sig figs AFTER the decimal point than the number with the lowest number. Answer cannot have more sig figs AFTER the decimal point than the number with the lowest number. Ex: = Ex: = Answer can only have 1 digit after the decimal Answer can only have 1 digit after the decimal Correct answer = 6.7 Correct answer = 6.7 Multiplying/Dividing Multiplying/Dividing Answer cannot have more sig figs than the number with the lowest number of sig figs. Answer cannot have more sig figs than the number with the lowest number of sig figs. Ex: 2.22 x = Ex: 2.22 x = has 3 sig figs and has 4 sig figs. Answer can only have 3 sig figs has 3 sig figs and has 4 sig figs. Answer can only have 3 sig figs. Correct answer = 5.21 Correct answer = 5.21 ±1 sig figs off is usually OK. If answer should have 4 sig figs and you have 3, 4 or 5, I won’t mark it wrong.

Objective d…Significant Figures But isn’t 50 and 50.0 and and even the exact same number? Maybe, outside of chemistry class, but not in here. Let me explain. 50 ≠ 50? Wha-hap- happen?

Objective d…Significant Figures 50 means that your measurement is somewhere between 49 and means that your measurement is somewhere between 49.9 and means that your measurement is somewhere between and means that your measurement is somewhere between and The more sig figs in your measurement, the more confidence you have that it’s “exactly” 50 mL or g.

Objective f…Density jpg Higher density layers on the bottom and lower density layers on the top. Is oil more or less dense than water? D = m / V

Objective g…Ice Floats Why does ice float? Why does ice float? Why is this a good thing? Why is this a good thing? Ice is actually kind of strange. Actually water is a very unique compound. Ice is actually kind of strange. Actually water is a very unique compound. Most substances are more dense as a solid than they are as a liquid. Most substances are more dense as a solid than they are as a liquid. Ice is an exception. Ice is an exception.

Objective h: Measure your Kinetic Energy: Take Your Temperature! Kelvin temperature was defined to be a measure of the kinetic energy of the sample of matter. 0K is ABSOLUTE zero. Kelvin temperature was defined to be a measure of the kinetic energy of the sample of matter. 0K is ABSOLUTE zero. A sample of matter at 300K has twice as much kinetic energy as a sample of matter at 150K. Temperature is directly proportional to kinetic energy. A sample of matter at 300K has twice as much kinetic energy as a sample of matter at 150K. Temperature is directly proportional to kinetic energy. You must remember how to convert from °C to K and vice versa. It WILL be on the test. You must remember how to convert from °C to K and vice versa. It WILL be on the test.

The End What is next? Unit 2: Chapter 5, 28, 13, and 14. We will do ALL of Chapter 5, but only portions of the other 3 chapters.