Problem Solving in Chemistry

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Chapter 4

• Problem Solving in Chemistry

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Steps to Solving ProblemsDimensional Analysis

• 1. Analyze - identify the given piece of
  information or data and the unknown (or what you
  are looking for)
• 2. Calculate - determine the conversions -
  determine the final answer in unit of unknown.

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Determine the number of pennies in one dollar,
going through nickels and dimes to determine the
answer.

• Identify the known and unknown.
• Known one dollar
• Unknown number of pennies

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First Conversion

• Convert one dollar to dimes, cancel out the
  dollar, change dimes to nickels, cancel out the
  dimes, convert nickels to pennies, cancel out
  the nickels - unit you are left in is the unit
  you should be looking for.
• 1 dollar 10 dimes 2 nickels 5 pennies
• 1 dollar 1 dime 1
  nickel

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Answer (1 x 10 x 2 x 5) ? (1 x 1 x 1) 100
pennies

• 1 dollar 10 dimes 2 nickels 5 pennies
• 1 dollar 1 dime 1
  nickel

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Converting between Units

• When you know the conversion, you can change
  anything.

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Converting between Units

• 1 day 24 hours
• 1 hour 60 minutes
• 1 minute 60 seconds
• 1 kilogram 1000 grams
• 1 milliliter 1 centimeter cubed (cm3)
• 1 liter 1000 milliliters
• 1 megagram 1000 kilograms
• 1 milligram 1000 micrograms
• 1 microgram 1000 nanograms
• 1 nanogram 1000 picogram

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Other Conversions

• 1012 microphones 1 megaphone
• 500 millinaries 1 seminary
• 10 cards 1 decacards
• 454 graham crackers 1 pound cake
• 10 millipedes 1 centipede
• 2 monograms 1 diagram
• 2 snake eyes 1 paradise
• 10-6 phones 1 microphone
• 10-12 boos 1 picoboo