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Do Now 11/3/14 Dimensional analysis is a problem solving method we used in Unit 1! We will be revisiting it today. 1. 2. Using dimensional analysis, solve the following problem: How many seconds are in 34.2 minutes? Round your answer above to the correct number of sig figs!! 3. What numbers do you think the following words represent? a. Pair d. Gross b. Dozen e. Gig c. Score By the end of the class period I will be able to… Define the term “mole” Use the concept of mole to convert between grams and moles of an element. Topic #1 Words that stand for numbers Pair = ? Dozen = ? Score = ? Gross = ? Gig = ? Pair = 2 Dozen = ? Score = ? Gross = ? Gig = ? Pair = 2 Dozen = 12 Score = ? Gross = ? Gig = ? Pair = 2 Dozen = 12 Score = 20 Gross = ? Gig = ? Pair = 2 Dozen = 12 Score = 20 Gross = 144 Gig = ? Pair = 2 Dozen = 12 Score = 20 Gross = 144 Gig = 1,000,000,000 Pair = 2 Dozen = 12 Score = 20 Gross = 144 Gig = 1,000,000,000 Mole = ???? What is mole?? Mole: a unit of measurement used in chemistry to express amounts of a chemical substance ‘Mole’ means 6.022x1023 Avogadro’s Number 6.022 x 1023 is also called “Avogadro’s Number” The mole is a HUGE number: 602,200,000,000,000,000,000,000 A mole of sand grains: Would cover all of the land in the continental United States to a depth of 3 inches! A mole of marshmallows: Would cover all of the land in the continental United States to a depth of 600 miles! A mole of baseballs If you wanted to make a bag to keep these baseballs in… The bag would need to be the size of our earth. If a mole of pennies: Was divided amongst every person on earth Each person would receive 1.5 x 1014 pennies That Means: Each person could spend: One million dollars a day for the next four thousand years! Conclusion: A MOLE is a really really really really really really really really really large amount. Stop and Jot How would you explain the definition of ‘mole’ to a 5th grader? Representative Particle A representative particle is the simplest unit of any substance. There are 6.022 x 1023 representative particles in a mole of any substance. Representative Particles For an element… For an ionic compound… For a covalent compound… An atom A formula unit A molecule Example: Au or O2 Example: NaCl Example: H2O So, what’s the representative particle in… A glass of water? So, what’s the representative particle in… A roll of quarters? Comparing Moles of Quarters and Dimes Compare a mole of dimes to a mole of quarters. What things would be the same? What would be different? Done early? Try to calculate how much money each would be! Dimensional Analysis a problem solving method that allows for conversion of one unit to another Conversion Factor: ratios used to convert a measured quantity to a different unit of measurement The MOLE Equivalence Statement 6.022x1023 atoms = an element’s mass # 1 mole = in grams The MOLE Equivalence Statement 6.022x1023 atoms = an element’s mass # 1 mole = in grams What does equivalence statement mean? Complete the following equivalence statement: 1 Dozen = 12 items Steps to convert: 1. Write what you are given (including units). 2. Write the unknown (what you are trying to calculate). 3. Create a conversion factor that has the given units on the denominator and the unknown units on the numerator. Moles to Atoms Atoms to Moles 1 mole of = 6.022x1023 atoms = an element’s mass # atoms in grams How many atoms are in a sample of 8.31 moles of calcium? 1 mole of = 6.022x1023 atoms = an element’s mass # atoms in grams How many moles are in a sample of 2.25 x 1023 atoms of neon? 1 mole of = 6.022x1023 atoms = an element’s mass # atoms in grams How many atoms are in a sample of 3.15 moles of phosphorus? 1 mole of = 6.022x1023 atoms = an element’s mass # atoms in grams How many moles are in a sample of 4.10 x 1024 atoms of potassium? Moles to Grams Grams to Moles 1 mole of = 6.022x1023 atoms = an element’s mass # atoms in grams How many moles are in a sample of 4.55 grams of carbon? 6.022x1023 atoms = 1 mole = an element’s mass # in grams How many grams of carbon are in a 12.24 mole sample of carbon? 6.022x1023 atoms = 1 mole = an element’s mass # in grams How many grams of magnesium are in 5.34 moles of magnesium? 6.022x1023 atoms = 1 mole = an element’s mass # in grams How many moles of nitrogen are in 36.05 grams of nitrogen? Atoms to Grams Grams to Atoms 1 mole of = 6.022x1023 atoms = an element’s mass # atoms in grams What is the mass of 1.47 x 1024 atoms of lead? 6.022x1023 atoms = 1 mole = an element’s mass # in grams How many atoms of nickel are in 150.4 grams of nickel? 6.022x1023 atoms = 1 mole = an element’s mass # in grams How many grams of bromine are in 8.02 x 1023 ions of bromine? 1 mole of = 6.022x1023 atoms = an element’s mass # atoms in grams How many atoms would you have if you measured out 36.8 g of sodium? 1 mole of = 6.022x1023 atoms = an element’s mass # atoms in grams Assignment… Molympics Prep Worksheet 1 mole of = 6.022x1023 atoms = an element’s mass # atoms in grams 1. What does “mole” mean in chemistry? 2. What is Avogadro’s number? 3. What is the mass in grams of 0.338 moles of iron?