Biology I. Building blocks of matter. Changes in Matter. Classification of Matter

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1 Building blocks of matter Atom - the smallest unit of an element that maintains the chemical identity of that element Element - a substance that cannot be separated into simpler substances. Biology I Compound - contains two or more elements in a fixed proportion. Chemistry Changes in Matter Physical change - changes the appearance but not the identity of the substance. Chemical change - changes the identity of the substance Law of Conservation of Matter: Matter is neither created nor destroyed in any process. Classification of Matter Matter can be either a pure substance (element or compound) or a mixture. Mixture - a blend of two or more pure substances eterogeneous mixture - a mixture that has visibly different parts. Ex: Chocolate Chip Cookie omogeneous mixture - a mixture that does not have visibly different parts. Ex: Sugar Cookie O O Na Cl 1

2 Notebook #1 What is an atom? 2. What is the relationship between an element and a compound? What is the difference between a physical change and a chemical change? 4. What is the law of conservation of matter? 5. What is the difference between a pure substance and a mixture? 6. What is the difference between a heterogeneous mixture and a homogeneous mixture? The Scientific Method The scientific method is a logical approach to solving problems by observing and collecting data, formulating hypotheses, testing hypotheses, and formulating theories that are supported by data. Qualitative - descriptive data Quantitative - numerical data ypothesis - if..then statement (an educated guess) : If water is at a high elevation over sea level, then it will boil more quickly, because the atmospheric pressure is lower. Accept or Reject a hypothesis The Periodic Table The elements are organized into groups based on similar chemical properties. This organization is known as the periodic table. Group - vertical column Period - horizontal rows Metal - good conductor of electricity and heat. Nonmetal - poor conductor of heat and electricity. Metalloid - some characteristics of metals and some of nonmetals. Noble Gases - last group of the periodic table, highly stable and unreactive. The Scientific Method Variable - the factor being tested Control - responds in a predictable way Theory - a broad generalization that explains a body of facts or phenomena. 2

3 Scientific Theory and Scientific Law A scientific law is a description of an observed phenomenon. Kepler's Laws of Planetary Motion are a good examples. Those laws describe the motions of planets. But they do not explain why they are that way. If all scientists ever did was to formulate scientific laws, then the universe would be very well described, but still unexplained and very mysterious. A theory is a scientific explanation of an observed phenomenon. Unlike laws, theories actually explain why things are the way they are. Theories are what science is for. If, then, a theory is a scientific explanation of a natural phenomena, ask yourself this: "What part of that definition excludes a theory from being a fact?" The answer is nothing! There is no reason a theory cannot be an actual fact as well. Notebook #2 What is the difference between a group and a period on the periodic table? 2. What is the scientific method? What is the difference between qualitative and quanitative data? 4. Why is a hypothesis used in an experiment? 5. Why must all science experiments have a control? Metric prefixes The Metric System SI Base Units - Standard system of measurement. Mass = kilogram (kg) Length = meter (m) Volume = Liter (L) Time = second (s) Temperature = Kelvin (K) Amount = mole (mol) Check your work Converting Units: Write down the word Given followed by any information (numbers) given in the problem. 2. Write down a? followed by the units to be solved for. Write down the conversion factor. 4. Start with the given and place over 5. Multiply by the conversion factor: The unit in the given is placed in the denominator of the next fraction and the conversion factor is arranged appropriately. 6. Cancel out any units that cancel. 7. Solve the problem with the new units in the answer. 3

4 Notebook #3 - Converting Units: ow many feet are in 648 inches? Notebook #4 Problems: Convert ow many seconds are there in 5.29 min.? Given: 648 inches 2. ow many quarters are there in 75.0 dollars?? : feet Convert 9.73g to centigrams 12 inches = 0 feet 4. Determine how many minutes there are in 76 hours. 5. Calculate the number of centimeters in 0.19 km. 6. ow many kg are in 37 mg. 7. *ow many seconds are there in one year? or x = Rules for determining significant figures involving zeros All nonzero digits are significant. Ex: 38g = 2 sig figs Zeros at the end of a number without a decimal point present are not significant. Ex: 5210g = 3 sig figs [I.e.: if there is a decimal point then they are significant!] Notebook #5 ow many significant figures are contained in each of the following measurements? 37.4 g ml Dm cm km m cm kg g Dm L Rules for determining significant figures involving zeros 4. Zeros at the beginning of a decimal number are not significant. Ex:.079g = 2 sig figs 2. All zeros between two nonzero digits are significant. Ex: 206g = 3 sig figs s quarters 973 cg min cm kg s K 5. All zeros to the left of a decimal point are never significant. Ex: 0.22g = 2 sig figs 6. All zeros at the very end of a decimal number are significant. Ex: g = 6 sig figs Rules for Rounding If the digit immediately to the right of the last significant digit you want to keep is: Greater than 5 increase by 1 Ex: (Round all to 3 digits) Less than 5 stay the same Ex: followed by a nonzero digit increase by 1 Ex: and preceded by odd digit increase by 1 Ex: and preceded by even digit stay the same Ex:

5 Interest Grabber Notebook #7 Notebook #6 - Round off each of the following measurements to the indicated number of significant digits: Round off m to the indicated number of sig figs g to 3 sig figs kl to 2 sig figs dm to 3 sig figs K to 2 sig figs cm to 2 sig figs g to 2 sig figs ml to 3 sig figs cm to 2 sig figs kg to 3 sig figs Rules for adding/ subtracting with sig figs When adding and subtracting numbers, the answer must have the same number of decimal places as the original number with the fewest decimal places. Example: m * least decimal place - ends in the tenth position 16.1 m m = m m Rules for multiplying/ dividing with sig figs When multiplying and dividing, the answer should have the same number of significant digits as the number in the original problem with the least amount of significant digits. Example: 750 cm x cm cm2 = cm2 (replace the 4 & 2 w/0) Perform the indicated operation and give the correct number of sig figs in answer g / 20 cm cm x 2.6 cm 4.07 g g cm cm g/ 2 cm dm x dm ml + 01 ml ml g / ml 9. (4.00 m)(0.020 m)(57 m) m m m * least sig figs (2) Notebook #8 Answer the following questions. Circle final answer! 25 m m m g/80 ml Round K to the tenths position. 4. (2.15 m)(0.042 m) cm cm 5

6 Answers # m = m g/mL = 12 g/ml 54.75K = 54.8 K m 2 = m cm = 12.4 cm Scientific Notation: Always place the decimal between the 1 st and 2 nd significant digits. 2. Drop zeros that are insignificant (only zeros) Multiply the new number by 10 raised to the exponent, which is the number of times the decimal was moved. 4. When a decimal is moved to the left the exponent is positive. When a decimal is moved to the right the exponent is negative. Scientific Notation: Addition/Subtraction with scientific notation must be the same base. Multiplying with scientific notation- add the exponents. Ex: (6.7x10 3 )(4.5x10 6 ) = 0x10 10 Dividing with scientific notation subtract the exponents. Ex: (4.2x10 8 )/(2.1x10 3 ) = 2.0x10 5 Problem #5 page 57 6