H Hydrogen Key. Li Lithium Be Beryllium Mg Magnesium Pa Protactinium

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1 Periodic Table of the Elements Chemistry Reference Sheet California Standards Test A 1 H Hydrogen Li Lithium Na Sodium A 4 Be Beryllium Mg Magnesium B 4 4B 5 5B 6 6B 11 Na Sodium B Key Atomic number Element symbol Element name Average atomic mass K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium (98) Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po Cesium Barium Lanthanum Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Mercury Thallium Lead Bismuth Polonium (209) Fr Ra Ac Rf Db Sg Bh Hs Mt Francium Radium Actinium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium (223) (226) (227) (261) (262) (266) (264) (269) (268) 9 8B * B Gold B 13 3A 14 4A 15 5A 16 6A 17 7A B C N O F Boron Carbon Nitrogen Oxygen Fluorine Al Si P S Cl Aluminum Silicon Phosphorus Sulfur Chlorine Br Bromine I Iodine At Astatine (210) 18 8A 2 He Helium Ne Neon Ar Argon Kr Krypton Xe Xenon Rn Radon (222) * If this number is in parentheses, then it refers to the atomic mass of the most stable isotope Ce Pr Nd Pm Sm Eu Gd Tb Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium (145) Th Thorium Pa Protactinium Dy Ho Er Tm Yb Lu Dysprosium Holmium Erbium Thulium Ytterbium Lutetium U Np Pu Am Cm Bk Cf Es Fm Md No Lr Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium (237) (244) (243) (247) (247) (251) (252) (257) (258) (259) (262) Copyright 2003 California Department of Education

2 PERIODIC TABLE OF IONS acetate CH 3 COO TABLE OF POLYATOMIC IONS 2 oxalate C 2 O 4 3 arsenate AsO 4 H 2PO dihydrogen phosphate 4 perchlorate ClO 4 3 arsenite AsO 3 hydrogen carbonate HCO 3 periodate IO 4 KEY atomic number 26 Fe 3+ ion benzoate C 6 H 5 COO HC 2O hydrogen oxalate 4 permanganate MnO 4 charge 3 borate BO 3 HSO 2 1 hydrogen sulfate 4 peroxide O 2 iron (III) ion 3 bromate BrO Fe 2+ name 3 HS hydrogen sulfide phosphate PO 1 4 symbol 2 (IUPAC) carbonate CO 3 hydrogen sulfite HSO 3 pyrophosphate P 2 O H + 7 iron (II) 2 chlorate ClO 3 hydroxide OH sulfate SO 4 H - He hydrogen 2 chloride Cl hypochlorite ClO hydride helium sulfite IO chlorite ClO 2 iodate thiocyanate SCN Li + Be 2+ chromate CrO 4 monohydrogen phosphate HPO 4 thiosulfate S 2 O 3 B C N 3- O 2- F - Ne lithium beryllium cyanate CNO nitrate NO 3 POSITIVE POLYATOMIC IONS boron carbon nitride oxide fluoride neon cyanide CN nitrite NO 2 ammonium NH 4 2 dichromate 4 Cr 2 O 7 orthosilicate SiO hydronium H 3 O Na + sodium Mg 2+ magnesium phosphide sulfiide argon Ti 4+ V 3+ Cr 3+ Mn 2+ Fe 3+ Co 2+ Ni 2+ Cu 2+ K + Ca 2+ Sc 3+ titanium (IV) vanadium(iii) chromium (III) manganese(ii) iron (III) cobalt (II) nickel (II) copper (II) Zn 2+ Ga 3+ Ge 4+ As 3- Se 2- Br - Kr potassium calcium scandium Ti 3+ V 5+ Cr 2+ Mn 4+ Fe 2+ Co 3+ Ni 3+ Cu + zinc gallium germanium arsenide selenide bromide krypton titanium (III) vanadium (V) chromium (II) manganese(iv) iron (II) cobalt (III) nickel (III) copper (I) Y 3+ Nb Zr 4+ niobium (V) Mo 6+ Ru 3+ Pd 2+ Sn 4+ Sb 3+ Rb + Sr 2+ Tc 7+ ruthenium(iii) Rh 3+ paladium(ii) Ag + Cd 2+ In 3+ tin (IV) antimony(iii) Te 2- I - Xe rubidium strontium yttrium zirconium Nb 3+ molybdenum technetium Ru 4+ rhodium Pd 4+ silver cadmium indium Sn 2+ Sb 5+ telluride niobium(iii) ruthenium(iv) paladium(iv) tin (II) antimony(v) iodide xenon La 3+ Hf 4+ Pt Au 3+ Hg 2+ Tl + Pb 2+ Bi 3+ Cs + Ba 2+ Ta 5+ W 6+ Re 7+ Os 4+ Ir 4+ Po 2+ platinum(iv) gold (III) mercury (II) thallium (I) lead (II) bismuth(iii) polonium(ii) At - Rn cesium barium lanthanum hafnium tantalum tungsten rhenium osmium iridium Pt 2+ Au + Hg + Tl 3+ Pb 4+ Bi 5+ Po 4+ platinum(ii) gold (I) mercury (I) thallium(iii) lead (IV) bismuth(v) polonium(iv) astatide radon Fr + francium Ra 2+ radium Ac 3+ actinium Ce 3+ Pr 3+ Sm 3+ Nd 3+ Pm 3+ Eu 3+ samarium(iii) europium (III) Gd 3+ Tb 3+ Dy 3+ Ho 3+ Er 3+ Tm 3+ Yb 3+ ytterbium(iii) Lu 3+ cerium praseodymium neodymium promethium Sm 2+ Eu 2+ samarium(ii) europium (II) gadolinium terbium dysprosium holmium erbium thulium Yb 3+ lutetium ytterbium(ii) Th 4+ Pa 5+ U 6+ protactinium(v) uranium (VI) Np 5+ Pu 4+ Am 3+ Bk plutonium(iv) americium(iii) Cm berkelium(iii) Cf 3+ Es 3+ Fm 3+ Md 2+ No 2+ mendelevium (II) nobelium(ii) Lr 3+ thorium Pa 4+ U 4+ neptunium Pu 6+ Am 4+ curium Bk 4+ californium einsteinium fermium Md 3+ No 3+ lawrencium protactinium(iv) uranium (IV) plutonium(vi) americium(iv) berkelium(iv) mendelevium (III) nobelium(iii) SO 3 2 Al 3+ aluminum Si silicon P 3- S 2- Cl - chloride Ar

3 List of Common Multivalent Ions The following elements form multivalent ions, and therefore require a Roman numeral charge when writing the name of the compound. Rare and synthetic elements are not included in this list. Element Sym. Possible Possible Element Sym. Charges Charges Titanium Ti +2, +3, +4 Tin Sn +2, +4 Vanadium V +2, +3, +4, +5 Rhenium Re +4, +6, +7 Chromium Cr +2, +3, +6 Osmium Os +3, +4 Manganese Mn +2, +3, +4, +7 Iridium Ir +3, +4 Iron Fe +2, +3 Platinum Pt +2, +4 Cobalt Co +2, +3 Gold Au +1, +3 Nickel Ni +2, +3 Mercury Hg +1, +2 Copper Cu +1, +2 Thallium Tl +1, +3 Niobium Nb +2, +5 Lead Pb +2, +4 Molybdenum Mo +3, +6 Bismuth Bi +3, +5 Palladium Pd +2, +4 Polonium Po +2, +4 Steps to Determine Charge from the Chemical Formula 1. Find total negative charge on all anions. 2. Divide value by number of cations to give charge on one multivalent cation.

4 Lab Safety Safety is essential in a science lab, due to the serious risks that can occur from mishandled chemicals, glassware and other material. It is vital that all students are aware of the lab s safety equipment, in particular where it is stored and how to use it. Additionally, students need to act in a conscientious and cautious manner when conducting an experiment or working in the lab. Safety Equipment Eyewash Station An eyewash is used to flush out one or both eyes if they have been contacted with a chemical or abrasive substance. In serious cases, flushing should occur immediately for at least five minutes (or more, depending on the nature of the substance) using a water faucet. First Aid Kit 1. The first aid kit contains a number of items for dealing with minor cuts, burns and scrapes. Inform Ms. Hayduk of any injuries incurred during a lab, regardless of how severe they are. Fire Extinguisher Fire extinguishers should be used for putting out small to medium sized fires that are uncontrolled. Before using a fire extinguisher, it is important to ensure it is appropriate for the type of fire. Class Use Symbol A Ordinary combustible materials (e.g. paper, wood, cardboard and most plastics) Green triangle B Flammable or combustible liquids (e.g. gasoline, kerosene, grease and oil) Red square C Electrical equipment Blue circle D Combustible metals (e.g. magnesium, potassium and sodium) Yellow decagon K Kitchen fires (e.g. cooking oil, trans-fats, fats) Black hexagon An ABC fire extinguisher, or an all-purpose fire extinguisher, is the most common, because it will put out the most common types of fire. Spill Kit 2. A spill kit contains a number of absorbent substances that can be used to neutralize and safety clean up chemical spills in the lab. A serious chemical spill includes substances that cannot be handled safely (highly corrosive) or an unknown mixture of chemicals. If a serious chemical spill occurs, find Mrs. Hayduk immediately; do not attempt to clean up the spill. Ensure that other students remain clear of the area. Personal Protective Equipment 3. Personal protective equipment refers to all clothing, helmets and eyewear designed to protect the wearer from injury. Prior to any lab, Ms. Hayduk will inform you which equipment is required to be worn during the activity. Students must wear all of this equipment for the duration of the lab, even if they have completed the activity.

5 Specific Emergency Procedures Fire If the fire is small, use the appropriate fire extinguisher on the fire or extinguish it with a lid or blanket. To use a fire extinguisher, follow the acronym PASS: pull out the pin, aim the nozzle at the base of the fire, squeeze the trigger and sweep the spray along the base of the fire until it is extinguished. If the fire is large and cannot be controlled, leave the room immediately and pull the fire alarm. All students should file out of the building in a calm manner to the designated meeting spot outside. The last student out of the room should shut the door to impede spread of the fire. If a fire alarm goes off during an experiment, students should shut off all gas and heat sources before exiting the lab. Spill Injury If the spill is a harmless substance (e.g. water, vinegar), clean it up immediately with rags or paper towel. If the spill is a more hazardous substance, inform Ms. Hayduk immediately. She will clean the spill with the spill kit. If possible, block the spill from spreading and remove any books, bags or personal items from the area. If more than one chemical spills in the same area, tell Ms. Hayduk and evacuate the room immediately. She will assess the danger and take steps to decontaminate the area For minor injuries, use the first aid kit. Make sure to clean any cuts or scrapes before applying a bandage. For serious injuries, inform Ms. Hayduk immediately and use a cell phone or the office phone to call 911. Make sure to tell EMS if the injury was caused by contact with a chemical (or broken glass contaminated with chemical). Laboratory Safety Procedures This list of safety procedures is general, and does not cover all aspects of safety in the lab. It is important that students use common sense and caution when working in the science lab, and ask for help when instructions or procedures are unclear. 1. Behave in a calm, professional, responsible manner at all times. 2. No food in the lab at any time. Beverages are allowed provided they are in re-sealable containers. Never eat any materials being used for experiments. 3. Use the appropriate personal protective equipment for the activity you (or others) are performing. Do not remove your PPE until you are instructed to do so by the teacher. 4. Keep yourself, your equipment and your workstation clean before, during and after the lab. Handle equipment with care. Wash glassware thoroughly with soap and water. After handling chemicals, wash hands thoroughly with soap and water. Keep aisles and table tops clear of bags and books.

6 5. Dispose of materials properly. Do not dump any chemicals down the drain unless instructed to by the teacher. Do not put any solid material in the drains. Sharp materials (e.g. dissection pins, broken glass) should be disposed of in the proper waste container never in the garbage can. 6. Do not touch any chemicals or equipment you have not been instructed to handle. Do not smell or taste chemicals. Do not try any unauthorized experiments. Do not enter the science storage room. 7. Never leave your lab station unattended. 8. Dress appropriately. Tie back long hair. Avoid wearing loose or dangling clothes or jewelry around chemicals or open flames. Wear closed-toed shoes. 9. Report any accident or incident immediately. Students who do not follow these safety procedures will be asked to leave the lab, and will be given an alternate written assignment to complete. WHMIS WHMIS stands for Workplace Hazardous Material Information System. It is a program designed to protect workers (e.g. students and teachers) who are handling chemicals on a regular basis. There are three key elements to WHMIS: 1. Labels, 2. Material safety data sheets; and, 3. Education and training. As a student, your primary concern will be with labels and material safety data sheets (MSDS). Labels The purpose of a WHMIS label is to identify the product as controlled and alert the user to the hazards and safe handling procedures of the product. The label provides a summary of the important information about the substance, including: 1. Name of chemical and common name 2. Hazard symbols 3. Risks associate with the substance and precautions to take when using it 4. First aid measures 5. Supplier information 6. Reference to MSDS, stating that more information is available Chemicals that are going to be stored in beakers, flasks or test tubes should be labelled with a name, date and some identifier of what is contained in it. If you are doing work in the lab and are planning to store chemicals, you must ensure this is done.

7 Hazard Symbols Class Controlled Product Dangers A Compressed Gas It is a gas kept under pressure Heat may cause the container to explode Drop or impact may cause the container to explode Compressed gases can be dangerous because the contents are under pressure, but also because the gas may be poisonous B Flammable and Combustible Material Material may burn at a low temperature, and may catch on fire from sparks, flame or friction May burst into flame in air or release a flammable gas if it comes into contact with water C Oxidizing Material Substance is a fire or explosion risk near flammable or combustible material May not burn itself, but could release oxygen or other gases that might make other materials burn more easily Material is a potentially fatal poisonous substance that could kill or cause permanent damage if inhaled, swallowed or absorbed through skin Poisonous and Infectious Material Division 1: Material Causing Immediate and Serious Toxic Effects Immediately dangerous to life and health Division 2: Materials Causing Other Toxic Effects Material is poisonous but not immediately dangerous May cause death or permanent damage as a result of repeated exposure over time May cause irritation D Division 3: Biohazardous Infectious Material An organism and the toxins they produce that may cause disease Corrosive Material Acidic or caustic materials that can eat through skin or corrode metals E Dangerously Reactive Material Substance could undergo dangerous reactions when subject to heat, pressure, shock or contact with other materials F

8 International Hazard Symbols Not all products and substances are controlled by WHMIS, so they may not have WHMIS labels or symbols. These are other symbols you may see on other household products. The border of the symbol represents the level of danger, and the symbol inside represents the specific hazard. Danger, shown with an octagon, is the biggest threat. Caution, given by an upside down triangle, is a smaller threat but should still be considered dangerous! Poison Danger Warning Caution Flammable Explosive Corrosive Material Safety Data Sheets Material safety data sheets (MSDS) are used to give more detailed information about the product than the information on the WHMIS label. The information includes: A description of the chemical Hazardous ingredients Physical and chemical data Fire and explosive hazard (how easily it will catch on fire or explode) Reactivity data Toxicological properties (how toxic it is to humans and other animals) Preventative measures to take when handling and storing it First aid measures to be taken if exposed When it was made and who to contact for more information MSDS are available online, as well as in a binder in the school. They are all current within three years for all of the chemicals available in the school. It is expected that all students will review the MSDS for important chemicals prior to every lab so they know the safety hazards and the personal protective equipment they should wear.

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10 Experimental Error and Measurements Accuracy and Precision Experimental error is the difference between a measurement and the true value, or between two measured values. This is measured by accuracy and precision. Accuracy tells how close a measured value is to the theoretical, accepted or true value. If this value is unknown, then the accuracy of a measurement cannot be determined. Precision measures how close two or more measurements are to each other. Precision can also be called repeatability or reproducibility. A measurement that is highly precise, or highly reproducible, will give values that are very close. Experimental Error Human errors are avoidable mistakes that come from mistakes, blunders or miscalculations. These are not considered sources of experimental error, since they can be eliminated by careful technique and by repeating the procedure correctly. Examples include spilling chemicals, using the wrong calculation or missing a step in the procedure. Systematic errors, or bias, are a type of experimental error that affect accuracy of a measurement. They are generally caused by flaws in equipment or in reading measurements, and are generally difficult to detect. These errors are one-sided, meaning they will usually give results that are close to each other, but are not close to the true value. Systematic errors can be caused by poor calibration of measuring instruments, poorly maintained or poorly constructed instruments and faulty reading of measurements by the user (e.g. reading volume at an angle). Random errors affect the precision of a measurement. These errors are two-sided because they can fluctuate above or below the true value in repeated trials. Random errors can be reduced by repeating the procedure and taking average values or by using better quality instruments. Common sources of random errors include estimating a measurement that is between graduations on an instrument or recording a value that fluctuates during the reading.

11 Sample Sources of Error Limited accuracy of measuring tools (how many decimal places the measurement can reasonably have) Contaminants on equipment or in chemicals Measuring tools not calibrated properly Impurities in chemicals Not enough trials or data Accidental spills or residue from pouring from one container to another Lots of measurements that increase uncertainty in calculations Not reading volumes and temperatures directly at eye-level Reaction does not go to completion Volumes are too small to read easily Calculating Experimental Error Accuracy of Equipment All measuring equipment has precision depending on the smallest unit of measurement on the instrument. Unless otherwise stated, the precision of a measurement can stated be up to 1/2 of the smallest unit, and the precision of that measurement is ±0.5 of the unit. For example, a ruler that has graduations of 1 mm can be used to measure a line that is 12.5 mm long, and that length is precise to ±0.5 mm. This is stated as 12.5 ±0.5 mm, which means the true value of the length is between 12 and 13 mm. Digital equipment and chemistry glassware generally has a specified accuracy that is written on the instrument. With glassware, some equipment is deliberately very precise (e.g. volumetric flasks), while others are not really intended to be used for measurements (e.g. beakers). Percent Error Percent error is the difference in accuracy between a measured, or experimental, value and the true, or accepted, value. It is calculated as follows: Experimental Accepted % Error = 100 Accepted The vertical lines on the top of the equation indicates absolute value, which means that negative signs are ignored. If you get a negative answer, record the value without the negative sign. Percent error can only be used if the true value is known, or can be calculated. Percent Difference Percent difference is used in place of percent error when the true value is unknown. It is used to find the precision of repeated measurements (experimental values, E). The equation used is: % Difference = E 1 E 2 ( E E 2 2 )

12 A Short Guide to Significant Figures What is a significant figure? The number of significant figures in a result is simply the number of figures that are known with some degree of reliability. The number 13.2 is said to have 3 significant figures. The number is said to have 4 significant figures. Rules for deciding the number of significant figures in a measured quantity: (1) All nonzero digits are significant: g has 4 significant figures, 1.2 g has 2 significant figures. (2) Zeroes between nonzero digits are significant: 1002 kg has 4 significant figures, 3.07 ml has 3 significant figures. (3) Zeroes to the left of the first nonzero digits are not significant; such zeroes merely indicate the position of the decimal point: o C has only 1 significant figure, g has 2 significant figures. (4) Zeroes to the right of a decimal point in a number are significant: ml has 2 significant figures, g has 3 significant figures. (5) When a number ends in zeroes that are not to the right of a decimal point, the zeroes are not necessarily significant: 190 miles may be 2 or 3 significant figures, 50,600 calories may be 3, 4, or 5 significant figures. The potential ambiguity in the last rule can be avoided by the use of standard exponential, or scientific, notation. For example, depending on whether 3, 4, or 5 significant figures is correct, we could write 50,6000 calories as: calories (3 significant figures) calories (4 significant figures), or calories (5 significant figures). What is a exact number? Some numbers are exact because they are known with complete certainty. Most exact numbers are integers: exactly 12 inches are in a foot, there might be exactly 23 students in a class. Exact numbers are often found as conversion factors or as counts of objects. Exact numbers can be considered to have an infinite number of significant figures. Thus, number of apparent significant figures in any exact number can be ignored as a limiting factor in determining the number of significant figures in the result of a calculation. Rules for mathematical operations In carrying out calculations, the general rule is that the accuracy of a calculated result is limited by the least accurate measurement involved in the calculation. 1

13 (1) In addition and subtraction, the result is rounded off to the last common digit occurring furthest to the right in all components. For example, 100 (assume 3 significant figures) (5 significant figures) = , which should be rounded to 124 (3 significant figures). (2) In multiplication and division, the result should be rounded off so as to have the same number of significant figures as in the component with the least number of significant figures. For example, 3.0 (2 significant figures ) (4 significant figures) = which should be rounded off to 38 (2 significant figures). Rules for rounding off numbers (1) If the digit to be dropped is greater than 5, the last retained digit is increased by one. For example, 12.6 is rounded to 13. (2) If the digit to be dropped is less than 5, the last remaining digit is left as it is. For example, 12.4 is rounded to 12. (3) If the digit to be dropped is 5, and if any digit following it is not zero, the last remaining digit is increased by one. For example, is rounded to 13. (4) If the digit to be dropped is 5 and is followed only by zeroes, the last remaining digit is increased by one if it is odd, but left as it is if even. For example, 11.5 is rounded to 12, 12.5 is rounded to 12. This rule means that if the digit to be dropped is 5 followed only by zeroes, the result is always rounded to the even digit. The rationale is to avoid bias in rounding: half of the time we round up, half the time we round down. General guidelines for using calculators When using a calculator, if you work the entirety of a long calculation without writing down any intermediate results, you may not be able to tell if a error is made and, even if you realize that one has occurred, you may not be able to tell where the error is. In a long calculation involving mixed operations, carry as many digits as possible through the entire set of calculations and then round the final result appropriately. For example, (5.00 / 1.235) (6.35 / 4.0)= = The first division should result in 3 significant figures; the last division should result in 2 significant figures; the three numbers added together should result in a number that is rounded off to the last common significant digit occurring furthest to the right (which in this case means the final result should be rounded with 1 digit after the decimal). The correct rounded final result should be 8.6. This final result has been limited by the accuracy in the last division. Warning: carrying all digits through to the final result before rounding is critical for many mathematical operations in statistics. Rounding intermediate results when calculating sums of squares can seriously compromise the accuracy of the result. 2

14 Significant Digits Flowchart

15 Unit Conversions and Scientific Notation Metric Unit Conversions To convert between metric units in the same category, use the staircase method: Tera Giga Mega Kilo Hecto Deca BASE Deci Centi Milli Micro Nano Pico T G M k h da d c m µ n p To move to a smaller unit, multiply by the number of steps it takes to get to the right prefix. For example, 5 km = ( ) cm = cm, since it takes five steps to get from kilo to centi. To move to a larger unit, divide by the number of steps it takes to get to the right prefix. For example, 30 mg = ( ) g = 0.03 g, since it takes three steps to get from milli to base. Scientific Notation Scientific notation is used for very large or very small numbers, which are common in science! It is written as a product (multiplication) between a number between 1 and 10 and a power of is a big number. It has a positive exponent is a small number. It has a negative exponent. Many scientific calculators have a button that allows the user to enter numbers in scientific notation. It may be EXP, 10 x, EE or y 1/x. It is important that students learn to use this function on their own calculator, to make calculations with scientific notation easier. To convert to scientific notation: 1. Create a number between 1 and 10 by moving the decimal (for whole numbers, it is after the last digit) to the left. There should be only one non-zero number before the decimal. 2. Count the number of spaces the decimal moves to determine the exponent on the 10. a. If the decimal moves left, the exponent is positive. b. If the decimal moves right, the exponent is negative. Example: = The decimal moved from the right of the last zero nine places to the left, which gives the exponent of 9. This number has four significant digits, but more could be added by putting zeros or removed by rounding (e.g to 3.35). To convert to standard form: 1. Multiply the two terms (the decimal between 1 and 10 and the power of 10) together; to ensure you are multiplying or dividing properly. Ask, Is it reasonable? after doing a calculation. If you get an answer of 1000 km in 1 m, and you know kilometres are much bigger than metres, you should recognize that the answer does not make sense and there was an error in the calculation. Comparing Values of Scientific Notation Numbers with higher exponents on the 10 are greater:

16 10 > 3 4 > -1-2 > -5 For numbers with the same exponent, numbers with a larger decimal value are greater: > > Factor-Label Method The factor-label method, also called dimensional analysis, is a problem solving method used for unit conversions and stoichiometric calculations. It is based on the idea of cancelling units to get the desired result. To get from one unit to another, conversion factors are used to change the units to the correct ones. Example: How many inches are in 32 km? The unit conversions here are: 1.6 km = 1 mile 1 mile = 5280 ft 1 ft = 12 inches A grid is used to show the work horizontal lines indicate divide (like in a fraction) and vertical lines indicate multiply (multiplication signs can also be used). 32 km 1 mile 5280 ft 12 inches 1.6 km 1 mile 1 ft Units that are on both the top and the bottom can be crossed out, like this: 32 km 1 mile 5280 ft 12 inches 1.6 km 1 mile 1 ft This leaves the answer in inches. To get the value, multiply the numbers on the top together, and divide by the numbers on the bottom: = ( ) ( ) = = inches Remember to ALWAYS include units in the final answer!! Common Unit Conversions Length Mass Volume 1 in = 2.54 cm 3.28 ft = 1 m 1 mile = 1.61 km 1 oz = 28.3 g 1 kg = 2.20 lb 1 fl oz = 29.6 ml 1 cup = 237 ml 1 mile = 5280 ft 1 ft = 12 in 1 lb = 16 oz 1 tbsp = 3 tsp 1 cup = 16 tbsp = 8 fl oz 1 US pint = 2 cups 1 US quart = 4 cups 1 US gallon = 16 cups Temperature C = ( F 32) 5 9 F = 9 C