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U4 One Step Stoichiometry Problems

U4 One Step Stoichiometry Problems. Chemistry Ms. Boon 10.10-10.11. Catalyst. 7 days = 1 week. 10 weeks. X. 7 days 1 week. 70 days. =. Pick up the notes handout and answer the following question at the top of the page:

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U4 One Step Stoichiometry Problems

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  1. U4 One Step Stoichiometry Problems Chemistry Ms. Boon 10.10-10.11

  2. Catalyst 7 days = 1 week 10 weeks X 7 days 1 week 70 days = Pick up the notes handout and answer the following question at the top of the page: 10 weeks have passed since the first day of school. How many days have passed? How do you know?

  3. Objective I can perform one-step stoichiometry conversions using a worksheet, notes, and a puzzle. I can show my work and use units in all my calculations.

  4. Mini Review: What is the mole? Think, Pair, Share: What is counting by weighing? Imagine you work at a candy store and a customer asks for 500 jelly beans. There is a long line and you do not want to count 500 beans. But you have a scale. What can you do? Answer: Find the weight of one bean. Then multiply by 500. Finally, measure this mass of beans and it should be 500 beans. The mole is a number we use to make counting atoms, ions, and molecules much easier. The mole allows scientists to count by weighing.

  5. Mini Review: What is the mole? • 1 mole = 6.02 x 1023particles. This does not change. • The number of particles in 1 mole is calledAvogadro’s number

  6. THE MOLE -- Why? • Why is the mole useful to us as chemists?? • Make a dot on your paper with your pencil. • Guess how many atoms of Carbon graphite are in that dot. • 25 million atoms in that tiny dot!

  7. Mini Review: What is the mole? Example 2: What is the molecular weight of baking soda? Hint: First find the mass of each element, then multiply by subscripts, then add up the answers. Example 1: What is the molar mass of aluminum? Hint: The molar mass is the same as the atomic mass, just add “g” for grams. Answer 26.98 g/mol AnswerNaHCO3 = 84 g/mol • Molar mass and molecular weight are the mass in gramsof one mole of an element or compound. • Different elements and compounds have differentmolar masses or molecular weights.

  8. Mini Review: What is the mole? Example 2: What is the molecular weight of baking soda? Hint: First find the mass of each element, then multiply by subscripts, then add up the answers. AnswerNaHCO3 = 84 g/mol 16 g x 3 48 g 1 g x 1 1 g 12 g x 1 12 g 23 g x 1 23 g = 84 g/mol + + + 5 minute - Quick Practice: Choose at least 2 molar mass/molecular weight problems from your worksheet.

  9. Stoichiometry Conversions Part 1: Grams to Moles and Moles to Grams. Ex 1: Moles to Grams. How many moles is 24 g of carbon? Ex 2: Grams to Moles. How many grams is 10 moles of Gold? Given: 24 g Unknown: # moles Conversion: 1 mol/12 g Set up: 24 g x 1 mol= 12 g Answer: 2 mol Given: 10 mol Unknown: # g Conversion: 197g/1 mol Set up: 10 molx 197 g = 1 mol Answer:1970 g 5 minute - Quick Practice: Choose at least 2 gram to mole or mole to gram problems from your worksheet. Calculating the molar mass or molecular weight of a chemical reveals the mass of one mole of that chemical. What if we are given more than one mole of a substance? Or some random amount in grams? Use the molar mass or molecular weight as a conversion factor to move between moles and grams.

  10. Stoichiometry Conversions Part 2: Particles to Moles and Moles to Particles. Ex 1: Particles to Moles. How many moles is 1.20 x 1024 atoms of carbon? Given: 1.20 x 1024 atoms Unknown: # moles Conversion: 1 mol/6.02 x 1023atoms Set up: 1.20 x 1024atoms x 1 mol= 6.02 x 1023atoms Answer: 2 mol Avogadro’s number allows us to determine the number of atoms, molecules, or ions (generally particles) in a given sample. Use 1 mole = 6.02 x 1023 as a conversion factor to move between moles and particles.

  11. Stoichiometry Conversions Part 2: Particles to Moles and Moles to Particles. Ex 2: Moles to Particles. How many atoms is 10 moles of Gold? Given: 10 mol Unknown: # atoms Conversion: 6.02 x 1023/1 mol Set up: 10 molx 6.02 x 1023atoms= 1 mol Answer:6.02 x 1024 atoms 5 minute - Quick Practice: Choose at least 2 particle conversion problems from your worksheet. Avogadro’s number allows us to determine the number of atoms, molecules, or ions (generally particles) in a given sample. Use 1 mole = 6.02 x 1023 as a conversion factor to move between moles and particles.

  12. Extra Special Bonus: Video Review – Super Hero Science How does the law of conservation of mass limit the size of a super hero? http://www.youtube.com/watch?v=fpV7DKwcqbk&list=PLJicmE8fK0EjcBM04Tz0UvUTJ3utyYD1G

  13. More Practice See textbook p. 224-233 Try the sample problems on p. 228 and 229

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