Chapter 1 and 2 Introduction to Chemistry

Quantitative vs Qualitative Quantitative – Measurements – Ex. 23 m, :46 s, 3.5 kg Qualitative – Observations – Deals with senses – Ex. Yellow, bitter, loud

Graphs and Charts – Pie Charts % or part of a whole

Graphs and Charts – Bar Graph Quantity over varied locations

Graphs and Charts – Line Graph Shows a relationship or trend of data Variable on the x- axis is the independent variable Variable on the y- axis is the dependent variable

Graphs and Charts – Line Graph Line of best fit – The line follows the overall movement of points – Use a straight edge

Theories and Laws Do theories become laws? Is a theory like a hypothesis?

Theories and Laws Theory – A true statement based upon facts and data that we have now. – Ex. Theory of Evolution Can a theory change? – Yes, theories can be modified when we get additional data or observations. Law – based on observable fact. – Theories can be used to explain laws. – Does not change. – Ex. Law of gravity

Pure Research vs Applied Research Pure research – Purely for gaining knowledge Applied research – Uses knowledge to solve a problem Ex. A chemist and a chemical engineer

SI Unit Standard International Unit How is it different from units that we use like feet or pounds? – Why is it important? Digits 0-10 Place … Ex. 12 – I have 1 group of 10 and 2 groups of 1

2 Types of Units Base – Defined unit of measurement – Time (s), length(m), and mass (kg) Derived – What does derived mean? – Comes from a combination of base units – Mph, g/ml, g/cm3

SI Base Units Time – s Length – m Mass - kg

Density – A Derived Unit What is the formula for density? – D = m/v Ex. 5.2 g occupy 15.6 mL – 5.2 g / 15.6 ml =.333 g /mL

Units of Measurement 231 What does this mean? – 231 lbs, 231 cm, 231 g Unit of measurement is important. Make sure you include this.

Pg = centi We will not use negative exponents for this 1 m = 10 2 cm

1 Mm = 10 6 m 1km = 10 3 m 1 m = 10 dm 1 m = 10 2 cm 1m= 10 3 mm 1m = 10 6 µm 1 m = 10 9 nm 1m = pm 1 ML = 10 6 L 1kL = 10 3 L 1 L = 10 dL 1 L = 10 2 cL 1L= 10 3 mL 1L = 10 6 µL 1 L = 10 9 nL 1L = pL

Mass Conversions You should see the relationship among the prefixes.

Test Taking Strategy Write down prefixes with conversions somewhere on the test.

1 mL = 1 cm 3

Conversion problems – Pg.34 #17

Group work Pg 34 #18

Temperature What does temperature actually measure? – Heat or amount of energy We will use Celsius and Kelvin What temperature does water freeze and boil? Can you go below 0 0 C? – Liquid nitrogen is C – Dry ice is C Can liquid water ever go above C?

The Kelvin Scale What is freezing point of water on the Kelvin scale? – 273 K What is 0 K? – Absolute 0 – This is as cold as it gets

Scientific Notation N x 10 n What part is the number? All of it 1 < m < 10 Precision is more precise than 0.2 N (integer)Magnitude (exponent) The greater the exponent the larger the magnitude +N(exponent)Larger -N(exponent)Smaller

Scientific Notation – x – x x – 1.2 x x 10 2 – 3 x x – 1 x 10 The number you end with must have the same value as the number you start with.

Scientific Notation Problems – Pg. 32 – #13 Group Work – #12

Data Analysis Interpolating Data – Data that comes from points on the line – Between extreme measured points Extrapolating Data – Uses the trend of a line to make a prediction – Does not come from measured points

Accuracy vs Precision Accuracy – Closeness to accepted value Precision – Reproducing a given measurement

Calculator Texas Instrument Programmable (Graphing)

Assign Calculators and Rules You will get your calculator everyday unless I tell you otherwise. Put your calculator number in your book by your name. Calculators are around $ Do not use anything other than you fingers to touch the calculator. No pens or pencils. Do not pick on the black rubber pieces on the back of the calculator. Do not mess with the batteries or the battery door. I need to know if your number is missing.

Percent Error

Percent Error Problems – Pg. 38 – #29 Group Work #30 Metric Conversions w/ scientific notation

Practice Problems cL to L m to km 3.13 cm 3 to mL 4.56 km to mm 5.29 kg to cg 6.25 kg/cL to g/L km/h to m/s minutes to seconds x 10 3 m to km x10 -6 g to ng

Homework Page , 80, 82, 86

Homework Review

Significant Digits Do this on your calculator What do you get? Are all of these numbers significant?

Significant Digit Rules 1.Non zero digits are significant 2.Embedded zeros are significant – What does embedded mean? 3.Placeholding zeros are not significant 4.Trailing zeros to the right of an explicit decimal are significant. – What is an explicit decimal? What is an implied decimal? 5.Counting numbers and constants never determine significance.

Significant Digit Rules Ex. Rule 1: All non zero digits are significant. How many significant digits are in: – – –

Significant Digit Rules Ex. Rule 2: Embedded zeros are significant. How many significant digits are in: – – –

Significant Digit Rules Ex. Rule 3: Placeholding zeros are never significant. How many significant digits are in: – 3100 – 40 –

Significant Digit Rules Ex. Rule 4:Trailing zeros to the right of an explicit decimal are significant. 560 and What’s the difference? – 560 can be in the range of – can be in the range of

Rule 4 continued How many significant digits are in:

Significant Digit Rules Ex. Rule 5: Counting numbers and constants will never determine significance. – Avogadro’s constant x10 23 – 6 molecules Numbers such as these would not be used to calculate the number of significant digits in your answer.

Calculations Using Significant Digits In your calculations you will use the least amount of significant digits for multiplication and division. – In the problem 3829 x 8100, what is the least amount of significant digits? – That is the one you will use in your answer. For addition and subtraction, you will round to the least place. – , what is the least place? – That is the place you will use in your answer

Addition and Subtraction –

Multiply and Divide x x / 1.223

Significant Digits Practice Give the number of significant digits for the following x x x 10 12

Understand? If you grasp the idea of significant digits then answer this. Write 100 with 2 significant digits.

Entering Exponents into Your Calculator x 10 2 You will enter then EE 2 Your answers will also show up in this format

Dimensional Analysis / Unit Conversion / Factor Label When adding and subtracting the units will remain the same. When multiplying the units will become squared. When dividing the units will cancel. You will always round to significant digits but the magnitude must remain the same. – Your answer is 4800 and must have 2 significant digits. – You would not put 4.8. The answer would be 4.8 x 10 3

Rules for Exponents X n x X m = X n+m X n / X m = X n-m (X n ) m = X n x m 1 / X n = X -n

Converting Squared or Cubed Units cm 3 is the same as cm x cm x cm Example: 3.6 m 3  mm m 3 x 10 3 mm x 10 3 mm x 10 3 mm 1 m 1 m 1 m Answer: 3.6 x 10 9 mm 3

Practice Problems 360s ms 4800g kg 25 kg µg 2.5 x µm pm 12.2 g/mL Kg/L 3.9 m 3 nm pm 2 m 2

Homework Pg. 51 # and Pg. 871 # 6

Homework Review

Chapter 2 Test Review