Introduction to the second semester of chemistry

Introduction to the second semester of chemistry : Introduction to the second semester of chemistry Mr. Shields

About the class : About the class We will cover much more material in the second semester. If you missed any information, you will have to go back and learn again. You will need a calculator with logarithmic functions. This will cost about ten to fifteen dollars.

About your teacher : About your teacher Bachelors in biology with minor in chemistry, eight years as a laboratory chemist with Oregon Department of Environmental Quality and earned a second bachelors in science at that time. M.Ed. In education. More work experience as a biologist with US Geological Survey in data analysis.

Expectations : Expectations Behavior Academic expectations

Behavior : Behavior We cannot conduct class without mutual respect. What does respect mean?

Respect : Respect Television depicts disrespect as funny and a normal part of life. Being disrespectful is not funny and can cause some serious problems for the comedian. Some people will say they forgive you, but will not really forgive.

Respect : Respect Respect means treating yourself and others with consideration.

Respect : Respect You may not have been treated with much respect in the past. You should be treated with respect. The first step is to treat others with respect.

Class Rules : Class Rules Be silent and pay attention when anyone is addressing the class. No offensive language. Ask for permission before leaving seat.

Academic expectations : Academic expectations You will be marked tardy if not ready when bell rings. There is a starting question every day. You must be ready with your notebook out to the starting question section.

Academic success : Academic success Only about one percent of students taking chemistry majors general chemistry will earn a degree in chemistry.

How to succeed : How to succeed The most important activity is that of concentrating in class. the students who succeed in college listen intently and take extensive notes. Problem-solving and test-taking skills are also important. Keeping current with homework is important.

Academic Success : Academic Success Most of the points in this class are in quizzes and exams. The people who do well pay close attention in class. At the end of last semester, I spent time talking with students who could not understand how they had a “C” when they finished all the assignments and did extra-credit work. They did not pay attention during class.

More on academic success. : More on academic success. Doing schoolwork at home and talking with friends during class is similarly a way to get poor results.

Other rules : Other rules You will need to paste the safety contract to the back of your notebook We have safety posters posted in the class room. They contain important information.

other : other Food? going to the bathroom? cell phones/video games? NO to food, water and gum. This is a rule for all science classes and really a rule for any type of science lab. No cell phones or video games. You will need to write a pass that I will sign and sign out to go to the bathroom.

Math skills : Math skills We will use several math skills in the second semester of chemistry. To succeed in any class you need a very good knowledge of the prerequisites. We will complete a math quiz so that I may determine your math skills and that I may help you address any deficits in math skills.

Study skills : Study skills You need to take notes, read the text, work problems and almost as important: ask questions. If you do not understand something, ask, someone else who is too shy will appreciate your asking.

Math Quiz : Math Quiz We need a quiz to find your strengths and weakness in the math needed for the second semester of chemistry. You will receive a score for completion of the quiz. Please take out a calculator and a pencil.

Review of math : Review of math Please take notes. Significant figures. Zeros in significant figures may be confusing. Leading and trailing zeros are just place-holders unless another digit proceeds or follows. E.g., 0.0005 or 1.0005; one and five significant Figures. Write in scientific notation

Significant figures. : Significant figures. 5.0 has two significant figures. If you would not ordinarily place a zero after the decimal, then you must have done so for a reason.

Practice : Practice 0.002 2.05 5.3 E -8

Starting Question : Starting Question F=ma mass is in kg, acceleration is in meters per second squared. What are the units of force? These are the units of a Newton.

Logarithms : Logarithms pH is a logarithmic scale. It is a log to the base ten scale, so each change of one is actually an increase of ten times. So an acid of pH 4 is ten times stronger than one of pH 5. The Richter scale is also a log to the base ten scale. An earthquake of 8 is 100x as powerful as a 6. We will use pH scales and other equations involving logarithms.

logarithms : logarithms A logarithm is a way to find or express an exponent. So a logarithmic scale is a sort of exponential scale. An equation may be written in exponential form or logarithmic form. Examples x = y^z or logy x = z Log 10 10 = 1 because any number to the first power is that number.

Math review : Math review To find a logarithm using most calculators, just enter the number and press the “log” key. “Ln” is log to base 2.7. After high school, “log” will mean log to the base ten unless specified otherwise. Log3 6: log 6/ log 3. A way of finding a solution since your calculator will not find unusual logarithms.

Find a hydrogen ion concentration from pH. : Find a hydrogen ion concentration from pH. pH is –Log 10 [H] Example.

Exponents and scientific notation. : Exponents and scientific notation. It does not matter in what order you do multiplication or division. So you can separate the two components of the scientific notation. Example.

Concentration of a solution : Concentration of a solution C1V1 = C2V2: this is the equation involving dilution. To find concentration: Divide moles of solute by liters of solution.

Percent yield : Percent yield Actual over theoretical times 100

Starting Question : Starting Question If your mouth had 10^6 bacteria after breakfast, and has 10^9 bacteria after lunch and will have 10^12 bacteria by the time you eat dinner, what is the shape of the graph of the growth of bacteria in your mouth?

Shape of exponential growth or decay. : Shape of exponential growth or decay. Rule: base has to be greater than zero If the exponent is greater than zero, the graph curves up. If the exponent is less than zero, the graph curves down. Good examples are the bacteria growing in your mouth and decrease of electrical charge in the capacitors of a radio power supply.

Derived units : Derived units You can make your own units. Miles per hour is an example. We have many derived units in chemistry. The constant R is a good example. It has units of atmospheres x liters / moles x Kelvins.

Roots of quadratics : Roots of quadratics We will need this for acid/base chemistry.

Exponents : Exponents Y = a x b ^x Y = 5 x 3 ^x

Logarithms : Logarithms Y = log a x a ^ x = y Log10 1= 0 10^0 = 1 Log10 10 = 1 Y = log10 100 = 2

Starting Question : Starting Question Why do atoms form bonds and what happens to their energy and stability when they do form bonds?

Objectives and reason for lesson : Objectives and reason for lesson We will finish reviewing the math needed for the second semester and review the two most important subjects in chemistry, bonding and nomenclature.

Today's activities : Today's activities We will take a quiz about ionic bonding and nomenclature, then we will correct the quiz and do some more review work in ionic bonding.

Answer to Homework : Answer to Homework Students will write answers on whiteboard.

Answers : Answers What is an ion? A molecule or an atom with a positive or a negative charge. What is an ionic compound? Answer: A compound made of a cation and an anion that is electrically neutral overall. What happens to both the energy and stability of neutral atoms as they form ionic compounds? Answer: Energy decreases and stability increases. Why do atoms become ions? a. To become more stable by gaining filled or half filled electron configurations.

Answers : Answers What holds ionic compounds together? Attraction between positive and negative charges, similar to attraction between north and south poles of a magnet. Restate the octet rule and explain how it will allow us to predict the charges taken by different atoms when they become ions. The octet rule says that the s block and the p block elements try to have just had eight valence electrons. 2 + 6 = 8. So atoms try to loose or gain. to have eight valence electrons. Which try to loose and which try to gain electrons? What is the net (total) charge on an ionic compound?

Answers : Answers 8. what are the rules for naming ionic compounds? Answer. The primary rules are to name the cation first, then the anion and add Roman numerals after cations that might have several different oxidation states. 9. What are the rules for writing a formula for an ionic compound? Answer: write the cation and anion, find the charges on each (use the periodic table and the Roman numerals that may follow the cation) and find the least common multiple between the two.

Answers. : Answers. 10. Explain the rules regarding naming compounds with transition metals. This includes lead and tin. Just add a Roman numeral after the cation to indicate the charge on the cation. 11. Why do we use Roman numerals after the transition metal? Because they usually have several possible oxidation states.

Homework : Homework P 169: 23, 24, 25, 28 Page 174: 30 all, 31 all. P. 180: 32 a and b, 33 a.

Starting question : Starting question Go to page 177 and 178 and find the percent composition by weight for Mg(ClO3)2 Find the kilograms of aluminum that will be recovered from 1000 kilograms of bauxite ore that is 18% Al2O3

Solution : Solution Find molar mass for Mg(ClO3)2 Divide the atomic mass of Mg by the molar mass of magnesium chlorite. First find the percent composition of aluminum in Al2O3. How much bauxite is in 1000 kg of ore?

Activities. : Activities. Review ionic bonding Finish the worksheet from yesterday. Put answers to homework on board. Review covalent bonding

Ionic bonding : Ionic bonding A fairly simple concept, atoms without filled valence shells will gain or lose electrons to achieve a noble-gas electron configuration. Ionic compounds form salts energy is released when salts are formed.

Slide50 : Polyatomic ions are molecules bonded with covalent bonds that have an electrical charge. Polyatomic ions can form salts. magnesium chlorate. Salts usually have a high melting and boiling point compared with covalent compounds.

Review yesterdays worksheet : Review yesterdays worksheet For example, Si

Turn to page 178 : Turn to page 178 Find the formula for a compound that is by weight 20% carbon and 80% hydrogen.

Compounds : Compounds Molecular compounds have lower boiling and melting points than ionic compounds. Molecular compounds have covalent bonds.

Tell your neighbor, what differences you find between these different types of compounds. : Tell your neighbor, what differences you find between these different types of compounds.

The covalent bond : The covalent bond Covalent bond involve sharing of electrons between atoms. There is a repulsion between the two protons and between the two electrons. These repulsions do increase the energy level of the atoms. However, when electrons are shared, partly filled orbitals are filled.

Lets try some problems. : Lets try some problems. Find the bond character for the following molecules: A. Rb-Br (2.0), Na-Cl (2.1), F-Cl (1.0), Ca-S (1.5), Mg-O (2.3), Cl-Cl (0), H-O in water (1.4) and the C-H bond in methane (0.4)

Hydrogen bonds : Hydrogen bonds These are a strong intermolecular force. They are very important in biology and chemistry. They are also not really bonds. They are just a strong attraction between some molecules.

Starting Question : Starting Question Turn to page 195 in your text and find if cesium fluoride is ionic, covalent or polar covalent. Make a guess as to if iron nitride is ionic, covalent or polar covalent. In addition, what would be an example of a bond that is strictly ionic, covalent or polar covalent.

Slide60 : Starting questions. How much progress am I making on my long term, short-term and medium-term learning goals? Do you feel in control of your own success? How to be an independent learner? You need to understand how to learn and what you may be missing. There are several things you have to do and if you miss one, you will experience frustration.

Starting Question : Starting Question What are you learning in chemistry? Why are you learning this information? How can I improve on what I am learning?