Name: Mrs. Krasniak 2014/15 Regents Chemistry

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1 Name: Mrs. Krasniak 2014/15 Regents Chemistry Unit 0 Math, Measurement and Lab Safety Unit 0? Yes! Before we can begin our discussion of Chemistry, we must brush up on some basic math skills that you will be using throughout the course. We also need to make sure that you can work safely and competently in the lab. Read through the objectives to see what is expected of you. Objectives: At the completion of the unit, you - will know and observe lab safety rules. will be able to make measurements of mass, length and volume to the appropriate precision based on the measurement tool. will be able to make calculations with measurements and record answers to the appropriate precision. will be able to work with very large and very small numbers utilizing scientific notation. will be able to convert a measurement in one measurement system to an equivalent measurement in a different measurement system or with different units. Chemistry Reference Tables: C, D and T Period Date Description 1 9/3/14 W Course Description and Policies Introduction to Chemistry Math Homework: Obtain course materials by Monday 9/8. Get Course Information Sheet and Safety Contract signed by Monday 9/8. Algebra Review Problems, page 16 2 Lab Laboratory Safety and Equipment Lab 3 9/4/14 Th 4 9/5/14 F Measurements in Chemistry Rules for Significant Figures Homework: Significant Figures Worksheet, pages 17 and 18 Scientific Notation and Using Scientific Notation with significant Figures. Homework: Scientific Notation Worksheet, pages 19 and 20 5 Lab Exploring the Metric System Activity 6 9/8/14 M Dimensional Analysis to convert measurements Work Due Today Laboratory Safety and Equipment Lab Homework: Dimensional Analysis Worksheet, pages 21 and /9/14 T More Dimensional Analysis Practice Got Calcium? Homework: Study for Safety, Measurement and Math Quiz 8 Lab Measurement and Unit Conversions Lab 9 9/10/14 Unit 1 The Structure of the Atom W 10 9/11/14 Th Quiz on Safety, Measurement and Chemistry Math (20 minutes) Work Due Today Measurement and Unit Conversions Lab 1 P a g e

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3 A Review of Algebra Skills Being comfortable with algebra is a requirement for success in regents chemistry. To make sure everyone is up to speed, let s review some of the important aspects: Steps to solving a word problem: 1. Read the problem. Then read it again, before writing anything down. 2. Write down all known information with units. Write down what needs to be found. 3. Write down the appropriate equation. 4. Rearrange the equation algebraically so that the variable being solved for is one side and all given information is on the other. 5. Substitute the known information into the equation with units. 6. Solve the equation. Record your answer with units and the appropriate number of significant figures. 7. CHECK your answer! The main idea of algebra is to find a number that satisfies an equation. Let's look at examples from chemistry. 1. A student measures the temperature of 20.0 ml of acetic acid and finds that it is 36.2 C. What is the temperature in Kelvin? 2. A sample of aluminum has a mass of 27.0 g. Aluminum has a density of 2.7 g/ml. What is the volume of this sample of aluminum? 3. How many moles of solute are needed to make 2.0 Liters of a 3.0 M solution? 3 P a g e

4 Direct and Inverse Relationships between Variables In nature, a change in one quantity usually leads to a change in another quantity. If second quantity undergoes the same change, this is a direct relationship. If the second quantity undergoes the opposite change, this is an inverse relationship. Example 1: Concentration of lemonade = powder water What happens to the concentration of lemonade if you add more powder, while keeping the same amount of water? What happens to the concentration if you add more water, while keeping the same amount of powder? Example 2: D = m V What happens to the value of D as m increases and V is constant? What happens to D when m decreases? What happens to the value of D as V increases and m is constant? When V decreases? Practice: spectators were at a B-Mets game. How many players were there? S = 10P 2. How many moles of solute are needed to make 5.0 Liters of a 3.0 M solution? 3. A balloon of Helium initially has a volume of 1.50 Liters at atmospheric pressure. The balloon is then placed in a hyperbaric chamber that is increased to twice atmospheric pressure. What is the new volume? P1 V1 = P2 V2 4 P a g e

5 Measurement Activity: Measurement is - Group Group Group Accuracy Precision Which set of data was most precise and why? Using the accepted values given, which set of data was the most accurate? 5 P a g e

How to make a Scientific Measurement 1. There is in EVERY scientific measurement. 2. The certainty of the measurement depends on the being used. 3. Every scientific measurement needs: and 4.

6 How to make a Scientific Measurement 1. There is in EVERY scientific measurement. 2. The certainty of the measurement depends on the being used. 3. Every scientific measurement needs: and 4. The significant figures of a measurement include all of the known digits, plus an estimate for the last digit. 5. The accuracy of a measurement can be expressed in terms of. 6. The formula is: 6 P a g e

7 Significant Figures Rules for Significant Figures Example: 3. Example: 4. Example: Example: Exceptions: Practice: How many significant figures do each of the following measurements have? g 2.50 ml 105,210 um 15 people g 7 P a g e

8 Adding and Subtracting with Significant Figures Rule: Example: Practice: g g g g g g g g Multiplying and Dividing with Significant Figures Rule: Example: Practice: 6.25 cm x 15 cm = 7320 g 2440 ml = m x 10 m = cm cm = m x 5321 m = m m = 8 P a g e

9 Review of Scientific Notation You have already seen and possibly used scientific notation in past math and science courses. This will be a review of the very LARGE and small numbers you will encounter throughout this course. Definition: Rules for Scientific Notation: 1. A number is expressed as the product of a coefficient and 10 raised to a certain power. Example: 6.02 x 10 23, 6.02 is the coefficient. 2. The coefficient must always be greater than or equal to 1, and less than 10. The decimal point is always located between the first and second digits. The first digit should never be 0! 3. The coefficient shows all of the significant figures in a measurement. Example: 300. = 3.00x = 3x10 2 Powers of Ten: 10 x Meaning x greater than 0 Represents number greater than 1 (10, 100, 1000, etc) x less than 0 Represents a fraction (.1,.01,.001) x= 0 By definition 10 0 = 1 Practice Problems: 1. Place the following numbers into scientific notation: a b c d P a g e

10 2. Convert the following numbers from scientific notation to standard notation: a. 1.2 x b x 10-4 c x 10-3 Mathematical Operations with Scientific Notation Multiplication: Add the exponents and multiply the coefficients. Then put the answer into proper form. Example: (6.0 x 10 5 )(5.0 x ) (6.0 x 5.0)( ) 30. x x Division: Subtract the exponents and divide the coefficients. Then put the answer into proper form. Example: (2.0 x 10 5 ) (4.0 x ) ( )( ) 0.5 x x 10-6 Addition and Subtraction: Convert the numbers to the same power of ten and then add or subtract the coeffieicnts. Then put the answer into proper form. Example: (6.0 x 10 5 )+(5.0 x 10 6 ) (6.0 x 10 5 )+(50. x 10 5 ) 56 x 10 5 Practice Problems: Solve the following problems. Make sure that your answer has the proper number of significant figures and is in proper scientific notation form. a. (6.03 x 10 5 )(3.2 x 10 1 )= b. (6.03 x 10 5 )(3.2 x )= d x 10 5 e x x x 10 4 c. (6.03 x 10 5 ) (3.2 x 10 6 )= 10 P a g e

11 Name: Date: Period: Fill in the blanks lines and boxes: What s in an Identity? 1 meter stick glue sticks blocks paper clip widths _1 meter (m)_ 1 meterstick 1 ( )_ 1 glue stick 1 ( ) 1 block 1 ( )_ 1 paper clip width 1 meter (m) 1 m _ 1 dm_ dm m 1 m _ 1 cm_ cm m 1 m _ 1 mm_ mm m We can use these relationships to convert from one unit to another unit. 1) How many centimeters are in 11.7 meters? 2) How many millimeters are in 3.2 meters? 11 P a g e

12 Making Cents of it All: Dimensional Analysis aka Factor Label Method In science (and in life) it is frequently necessary to convert between units of measurement. A good example is converting between dollars and quarters, dimes, or nickels: $1.00 = 1 dollar bill = 4 quarters = 10 dimes = 20 nickels Each expression above shows the same monetary value, simply in different units. Notice that as the units get smaller and smaller, the number needed to equal a dollar becomes larger and larger. A nickel is 1/20 the size of a dollar, therefore you need 20 times as many nickel to have the same total amount of money. This comparison of the units nickel and dollar is helpful in creating a conversion factor. Conversion Factor: We know that 20 nickels are needed for every dollar. Therefore our ratio is: 20 nickels or 1 dollar 1 dollar 20 nickels Both ratios are correct, and both ratios equal one. So when do we use each? Know where you re starting and where you are headed! In order to know which ratio to use you have to know which units you re starting with, and which you re ending with. For example, if I want to make 3 dollars into nickels, I d use the following equation: 3 dollars x 20 nickels = 60 nickels 1 dollar Let's try this one: ** Note - The unit I want to end up with is in the numerator and the unit I began with is in the denominator. When setting up a conversion factor you should always have the unit you want to get rid of in the place where it will cancel out. How many quarters are in $6.25? 12 P a g e

13 Dimensional Analysis Practice: 1. Convert $229 dollars into British Pounds. $1 =.57 Pounds (as of 9/9/2008) 2. Convert 15 inches into centimeters. 1 inch = 2.54 cm 3. Using problem 3, convert 15 inches into millimeters. 4. Convert 5 pounds into kilograms Kg = 1 lb. 5. Convert 50 oz into kilograms. 1 lb = 16 oz. 6. Convert 28 days into seconds. 7. Convert 1.5 x 10 9 years into seconds. Be sure to give your answer in scientific notation. 13 P a g e

Got Calcium? (adapted from NASA's Imagine the Universe) Except on Earth, the Milky Way galaxy doesn't contain any milk. But it sure does have a lot of calcium.

In fact, all of the elements that make up your body and the planet Earth itself, other than hydrogen and helium, were made in stars or during explosions of massive stars.

In addition to energy, the fusion process in massive stars (stars having more than 8 times the mass of our sun) results in carbon, nitrogen, iron and other atoms.

14 Got Calcium? (adapted from NASA's Imagine the Universe) Except on Earth, the Milky Way galaxy doesn't contain any milk. But it sure does have a lot of calcium. There's enough calcium floating between the stars to fortify trillions upon trillions of gallons of milk. Calcium comes from stars. In fact, all of the elements that make up your body and the planet Earth itself, other than hydrogen and helium, were made in stars or during explosions of massive stars. Stars are like mighty chemical factories. They burn hydrogen and helium through a process of nuclear fusion, which produces a tremendous amount of heat energy. In addition to energy, the fusion process in massive stars (stars having more than 8 times the mass of our sun) results in carbon, nitrogen, iron and other atoms. As iron accumulates in the stellar core, the fusion process no longer produces heat energy. At this point in the life of a massive star, the core collapses and the star explodes, sending all those atoms racing into space. Some atoms bump into each other in the fury, fusing to create even heavier atoms such as gold, silver and uranium. These atoms spread across the galaxy over the course of billions of years. Cassiopeia A is a star that exploded about 320 years ago. No astronomer recorded the explosion at the time, but we can still see the remains of the explosion today in the form of a colorful supernova remnant. By measuring the motion of the gas in the remnant, astronomers deduce its age. Optical: Visible light image of Cassiopeia A (from a telescope on Earth) X-ray image of Cassiopeia A (from Chandra X-ray Observatory X-ray image showing only the calcium present in Cassiopeia A The Michigan-Dartmouth-Massachusetts Institute of Technology Observatory on Kitt Peak, Arizona, captured a beautiful image of Cassiopeia A in visible light (above, left). In an image accumulated over a million seconds, The Chandra X-ray Observatory, an earth-orbiting satellite, saw the hot X-ray-emitting gas from the explosion (above, middle). This gas is hotter than the surface of the sun. Chandra was also able to see the individual elements within the explosion. For example, researchers at NASA's Goddard Space Flight Center created an image showing only the element calcium (above, right). 14 P a g e

15 How much calcium is in Cassiopeia A? Use the following information to find out: The star that produced the supernova remnant Cassiopeia A was about 20 times more massive than the Sun. It was largely made up of hydrogen but also contained some calcium and other elements. When the star exploded, the hydrogen, calcium, and other elements produced by fusion during the life of the star fly off into space. The explosion creates more of these and other elements. The total amount of calcium is equal to about 0.05% of the mass of the original star. One glass of milk (8 fluid oz. or 237 ml) contains approximately 300 mg of calcium. There are 8.44 x 10 6 milk cows in the United States. On average, each cow produces 26.3 kg of milk/ day. Using this information, answer the following questions. Use dimensional analysis and show all your work. 1. The mass of the sun is 2.0 x kg. What is the mass of Cassiopeia A? 2. How many kilograms of calcium are in the supernova remnant Cassiopeia A? 3. How many 8-ounce glasses of milk would this equal? 4. How long must the cows in the United States be milked to produce this number of glasses of milk? 15 P a g e

16 Alegbra Review Worksheet Name: Date: Period: Solve for the unknown quantity in each of the following questions. Make sure to follow the 7 steps for solving problems and make sure to use the appropriate units. 1. A sample of a substance is found that has a mass of 21.0 g and a volume of 7.01 ml. What is the density of the substance? 2. A different sample of the same substance has a density of 3.0 g/ml and a mass of 93.0 g. What is the volume of this sample? Joules (J) of heat is added to a 200 gram (g) sample of water. The heat capacity of pure water is 4.18 J/g K. How much did the temperature of the water change when 125 J of heat was added? 4. How much did the temperature change in question 3 in degrees Celsius? 16 P a g e

17 Significant Figures Worksheet Name: Date: Period: Determine the number of significant figures in each of the following numbers g g cm lb g g cm ml g lb cm cm x x oz g mg x x x 10 3 Add the following measurements and record the answer with the appropriate number of significant figures cm cm cm = cm cm = g g g g = g g g g = cm cm cm cm = 17 P a g e

18 Subtract the following measurements and record the answer with the appropriate number of significant figures cm cm = g 43.7 g = ml = 28.9 ml = g 39.9 g = ml ml = Multiply the following measurements and record the answer with the appropriate number of significant figures cm x 4.01 cm = cm x 6.2 cm = m x 1.2 m = mm x mm = dm x dm = Divide the following measurements and record the answer with the appropriate number of significant figures cm cm = m m = ,789.4 km km = mm mm = cm cm = 18 P a g e

19 Scientific Notation Worksheet Name: Date: Period: Express each of the following numbers in scientific notation with the appropriate number of significant figures = = 2. 50,000. = ,000,000 = = = ,000 = = Express each of the following as common numbers x 10 5 = x 10-4 = x 10 5 = x 10-3 = x = x = 19 P a g e

20 Perform each of the following operations using scientific notation. Your answers should have the appropriate number of significant figures. 15. (2.3 x 10 3 )(4 x 10 5 ) = 16. (9.6 x 10-1 )(5.21 x 10 2 ) = 17. (4.56 x 10-6 )(3.1 x 10-3 ) = 18. (5.7 x 10 8 )(2.3 x 10-4 ) = x 10 2 = 1.3 x x 10 4 = 9.0 x (1.3 x 10 5 )(8.2 x 10-2 ) = 7.4 x x x x x x x x x P a g e

21 Dimensional Analysis Worksheet Name: Date: Period: Directions: Answer the following questions using dimensional analysis. Be sure to report your answer with the appropriate number of significant figures. You must show your work!! 1. A bottle of water holds 0.5 liters. How many cl of water is this? 2. The world record for the long jump is 8.95 meters. How many decimeters is that? 3. A standard tennis ball has a mass of 57.0 grams. How many micrograms is that? 4. The heaviest weight ever lifted by a human is 51.7 kg. How many grams is that? 5. According to the Village of Endicott s annual water report, one of the wells that supplies water to residents contains 89.6 mg/l of sodium. How many g/l of sodium does the water contain? 6. The Pacific Giant Kelp is the longest growing kelp at 600 cm long. How many inches long is it? ( 1 inch =2.54 cm) 7. The biggest piece of fudge ever created weighted 1367 kg. How many pounds was it? (1 lb =.454 kg) 21 P a g e

22 8. Carbonated beverage bottlers usually put 355 ml of soda in a can. How many cups is that? (1 oz = ml and 8 oz = cup) 9. How many seconds old are you? (round your age to the nearest.1 year) 10. Each liter of air has a mass of 1.80 grams. How many liters of air are contained in 2500 kg of air? grams of Doritos contains 5.0 calories. Each bag of Doritos contains 28.0 grams. How many bags would you need to eat in order to consume 2150 Calories? 12. The moon is 384,403 km from the earth. Estimate how many quarters laid end to end it would take to reach the moon if a quarter has a diameter of 2.3 cm. 22 P a g e

Name Date Class MEASUREMENTS AND THEIR UNCERTAINTY

Name Date Class MEASUREMENTS AND THEIR UNCERTAINTY 3.1 MEASUREMENTS AND THEIR UNCERTAINTY Section Review Objectives Convert measurements to scientific notation Distinguish among the accuracy, precision, and error of a measurement Identify the number of