Chemistry is a team sport! Come to class prepared to participate! Chemistry is a team sport! Be on time and here for all classes! Practice is required!

Building A Conceptual Understanding     Building A Conceptual Understanding Microscopic – the particulate nature of matter The atomic level (abstract) Symbolic – mathematical equation or chemical equation Macroscopic - observations or results of an experiment How we represent it The visible world or How we SEE it

A Brief History of Chemistry

Approx. 15 Billion Years Ago BANG !

What is the most important chemical reaction on Earth?

Photosynthesis 6 CO2 + 6 H2O  C6H12O6 + 6 O2

What were some of the first chemical transformations undertaken by humans?

Respiration (digestion) C6H12O6 + 6 O2  6 CO2 + 6 H2O Glucose

Combustion Reaction (Ideal) CxHy + O2  CO2 + H2O

Making beer from barley in ancient Egypt - 4000 BC

Fermentation C6H12O6  2 C2H5OH + 2 CO2 Glucose Ethanol

Smelting of Copper - 4000 BC

SMELTING CuO + C CO2 + Cu

Bronze Age - 3100 BC

Iron Age - 1200 BC

Soap - 800 AD

Greek Philosophers (400 - 300 BC) Democritus Aristotle

Alchemy

Herbal medicines

Gunpowder

Age of steel

What has modern chemical knowledge and research brought to the world?

Phenol - First Antiseptic

Discovery of chloroform for anesthesia

Salicylic acid (first extracted from the bark of the Willow tree)

Acetyl salicylic acid (“Aspirin” or ASA)

H H morphine

The Age of Plastics (Polymers)

Unit Conversions MEASUREMENT Dimensional Analysis, Scientific Notation, Significant Figures, Density, Percent Error

A. SI Prefix Conversions Symbol Factor mega- M 106 kilo- k 103 BASE UNIT --- 100 deci- d 10-1 move left move right centi- c 10-2 milli- m 10-3 micro-  10-6 nano- n 10-9 pico- p 10-12

Mnemonic Device Kids Have Dirty Mouths, Lips, Gums Drinking Chocolate Milk Many Never Pretend

Chemistry Reference Table - Table C

A. SI Prefix Conversions 0.2 1) 20 cm = ______________ m 2) 0.032 L = ______________ mL 3) 45 m = ______________ nm 4) 805 dm = ______________ km 32 45,000 0.0805

Packet page 1

B. Dimensional Analysis The “Factor-Label” Method Units, or “labels” are canceled, or “factored” out

B. Dimensional Analysis Steps: 1. Identify starting & ending units. 2. Line up conversion factors so units cancel. 3. Multiply all top numbers & divide by each bottom number. 4. Check units & answer.

B. Dimensional Analysis Lining up conversion factors: = 1 1 in = 2.54 cm 2.54 cm 2.54 cm 1 = 1 in = 2.54 cm 1 in 1 in

B. Dimensional Analysis How many milliliters are in 1.00 quart of milk? qt mL 1.00 qt 1 L 1.057 qt 1000 mL 1 L = 946 mL 

B. Dimensional Analysis You have 1.5 pounds of gold. Find its volume in cm3 if the density of gold is 19.3 g/cm3. lb cm3 1.5 lb 1 kg 2.2 lb 1000 g 1 kg 1 cm3 19.3 g = 35 cm3

Packet Page 2-3 Homework finish pages 2-3

Scientific Notation A short-hand way of writing large numbers without writing all of the zeros.

The Distance From the Sun to the Earth 93,000,000

Step 1 93,000,000 = 9.3000000 Move decimal left Leave only one number in front of decimal 93,000,000 = 9.3000000

Step 2 Write number without zeros 93,000,000 = 9.3

Step 3 7 93,000,000 = 9.3 x 10 Count how many places you moved decimal Make that your power of ten 93,000,000 = 9.3 x 10 7

The power of ten is 7 because the decimal moved 7 places. 7 93,000,000 = 9.3 x 10 7

93,000,000 --- Standard Form 9.3 x 107 --- Scientific Notation

Practice Problem -----> -----> -----> -----> Write in scientific notation. Decide the power of ten. 98,500,000 = 9.85 x 10? 64,100,000,000 = 6.41 x 10? 279,000,000 = 2.79 x 10? 4,200,000 = 4.2 x 10? 9.85 x 107 -----> 6.41 x 1010 -----> 2.79 x 108 -----> -----> 4.2 x 106

Scientific Notation to Standard Form Move the decimal to the right 3.4 x 105 in scientific notation 3.40000 --- move the decimal ---> 340,000 in standard form

Move the decimal to the right. Write in Standard Form Move the decimal to the right. 6.27 x 106 9.01 x 104 6,270,000 90,100

Homework Page 5

DETERMINING SIGNIFICANT FIGURES Crunching numbers with accuracy and precision

BEFORE YOU CAN CRUNCH You must know which digits are significant Because they are going to control the number of digits in a calculated figure 4/4/2019

WHAT IS A SIGNIFICANT FIGURE? Significant figures are all the digits in a measurement that are known with certainty plus a last digit that must be estimated. 4/4/2019

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Now you try How many significant digits in each of the following: 12 apples 3000 m 69 people 4/4/2019

Answers 1.034 s - 4 significant figures 0.0067 g - 2 significant figures 12 apples - exact number 3000 m - 1 significant figure 69 people - exact number 4/4/2019

CALCULATING WITH SIGNIFICANT FIGURES Crunching numbers with accuracy and precision

SIGNIFICANT FIGURES Are important in calculations. Significant figures tell you when and where to round. The number of digits in a calculated number is dependent on the significant figures of the terms used in the calculation. 4/4/2019

ROUNDING Rounding in science is different than in math. What if the digit to be dropped is: >5  round previous digit up one <5  do not change previous digit = 5 If the previous digit is even, do not change it If the previous digit is odd, round it up to make it even 4/4/2019

ROUNDING EXAMPLES – Round to 3 significant figures 12.379 cm = 12.4 cm 356.329 L = 356 L 0.03455 g = 0.0346 g 1.6857 s = 1.68 s 4/4/2019

Now you try Round to the nearest tenths place 15.265 m 1.33 s 0.9543 g 2.6597 cm 105.0356 L 0.0698 kg 4/4/2019

Answers 15.265 m - 15.3 m 1.33 s - 1.3 s 0.9543 g - 1.0 g 2.6597 cm - 2.6 cm 105.0356 L-105. 0 L 0.0698 kg - 0.1 kg 4/4/2019

CRUNCHING NUMBERS Multiplication and Division Addition and Subtraction 4/4/2019

MULTIPLICATION AND DIVISION An answer has the same number of significant figures as the number in the least precise measurement used in the calculation. 36 cm x 1.03 cm = 37.08 cm2 36 is the least precise measurement with 2 significant figures. Therefore the answer can have only 2 significant figures The answer is 37 cm2 4/4/2019

ADDITION AND SUBTRACTION The answer has the same number of decimal places as the least precise measurement used in the calculation. 12.11 18.0  Limiting term has one decimal place 1.013 31.123 Corrected to 31.1 (one decimal place) The correct result is 31.1, since 18.0 has only one decimal place. 4/4/2019

Now you try 0.356 kg x 1.5 m 1.234 g + 0.67 g + 13.2 g 101 g / 0.33 mL 15.27 s – 3.695 s 4/4/2019

Answers 0.356 kg x 1.5 m = 0. 53 kgm 1.234 g + 0.67 g + 13.2 g = 15.1 g 101 g / 0.33 mL = 310 g/mL 15.27 s – 3.695 s = 11.58 s 4/4/2019

Homework page 18 & 20

MEASUREMENT I. Using Measurements

A. Accuracy vs. Precision Accuracy - how close a measurement is to the accepted value Precision - how close a series of measurements are to each other ACCURATE = CORRECT PRECISE = CONSISTENT

B. Percent Error your value accepted value Indicates accuracy of a measurement your value accepted value

B. Percent Error % error = 2.9 % A student determines the density of a substance to be 1.40 g/mL. Find the % error if the accepted value of the density is 1.36 g/mL. % error = 2.9 %

D. Density V = 825 cm3 M = DV D = 13.6 g/cm3 M = (13.6 g/cm3)(825cm3) An object has a volume of 825 cm3 and a density of 13.6 g/cm3. Find its mass. GIVEN: V = 825 cm3 D = 13.6 g/cm3 M = ? WORK: M = DV M = (13.6 g/cm3)(825cm3) M = 11,200 g

D. Density D = 0.87 g/mL V = M V = ? M = 25 g V = 25 g 0.87 g/mL A liquid has a density of 0.87 g/mL. What volume is occupied by 25 g of the liquid? GIVEN: D = 0.87 g/mL V = ? M = 25 g WORK: V = M D V = 25 g 0.87 g/mL V = 29 mL