Do Now: Part 1: Match each diagram with its correct description. Diagrams will only be used once.

Transcription

1 Chemistry Ms Ye Name Date Block Do Now: Part 1: Match each diagram with its correct description Diagrams will only be used once 1 Pure Element only one type of atom present 2 Mixture of two elements two types of uncombined atoms present 3 Pure compound only one type of compound present 4 Mixture of two compounds two types of compounds present 5 Mixture of a compound and an element Part 2: For each of the following substances, determine whether it is an element (E), a compound (C), a Heterogeneous Mixture (HetM), or a Homogeneous Mixture (HoM) 1 Steam (H2O gas) 2 Salt Water 3 Pencil lead (C) 4 Dirt 5 Silver (Ag) 6 A burrito 7 Italian Dressing 8 Chicken Soup 9 Lemonade

2 What is a Mole? Watch the video ( and answer the questions: 1 How many donuts are there in: a A dozen donuts? b A mole of donuts? 2 How many jellybeans are there in: a 1 dozen jellybeans? b 1 mole of jellybeans? 3 What are different ways we can express the quantity 602,000,000,000,000,000,000,000? a (in words): b (in scientific notation): c Number 4 1 mole of jellybeans will take up how much space? 5 How long/tall is a stack of 1 mole of donuts? 6 1 mole of Sulfur atoms will take up how much space? What does this tell you about the relative size of atoms? 7 Since we can t count 10,000 jelly beans or 1 mole of Sulfur atoms, what can you do? 8 What is the molar mass for a substance? 9 Atoms of different elements have different masses, so 1 mole of carbon will weigh than 1 mole of sulfur

3 Molar Mass: The mass of one mole of a substance Percent Composition: Identifies the elements present in a compound as a mass % of the total compound mass How to calculate Molar Mass & Percent Composition of an element in a compound: 1 Identify or determine the molar mass 2 Divide the total mass of each element by the of the compound (in grams) molar mass Multiply by 100% to convert to Ex: K2CO3 a percentage K: 2 x 391 grams = 782 grams C: 1 x 120 grams= 120 grams %K = 100% = % O: 3 x 160 grams = 480 grams %C = 100% = % Molar Mass= 1382 grams %O = 100% = % Practice: Molecular Formula Mg(OH)2 Molar Mass of Compound % Composition of Each Element CrF3 Al2(SO4)3 KNO3

4 How to Convert from Grams to Moles 1 Determine 2 If necessary, calculate the mass of the molar mass for that your substance substance If it is given, that you are use that value interested in Sample problem: How many moles of KCl are in 260 grams of KCl? 1 x x 355 = 3 Use dimensional analysis to solve for moles 260 = = How to Convert from Moles to Grams 1 Determine 2 If necessary, calculate the # of moles the molar mass for that of your substance If it is given, substance that use that value you are 1 x x 160 = interested in Sample problem: How many grams of CO2 are in 15 moles of CO2? 3 Use dimensional analysis to solve for mass = = Practice: Calculate the number of moles or grams equivalent to the samples below (you may need to find the molar mass first): 1 30 grams of H3PO4 (MM=98 grams/mole) = moles H3PO grams of HF = moles HF grams of CO2 = moles CO moles of C6H6 = grams C6H6

5 5 213 moles of BaCO3 (MM=19733 grams/mole) = grams BaCO moles of ZnO (MM=8141 grams/mole) = grams ZnO ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Atom vs Molecule Atom: Can refer to Molecule: Can refer to ***Remember: How to Determine the Number of Molecules or Atoms in a Sample 1 Determine the given amount of your substance and what you re looking for Sample Problem: How many molecules of CO2 are in 660 grams of CO2? 3 Use dimensional analysis to solve for molecules = 2 If necessary, calculate the molar mass for that substance If it is given, use that value 1 x x 160 Practice: 1 Nitroglycerin: C3H5N3O9, molar mass grams/mole How many molecules of nitroglycerin are in 568 grams of nitroglycerin? = 2 Calcium Phosphate: Ca3(PO4)2, molar mass 310 grams/mole How many molecules of calcium phosphate are found in a 225 gram sample?

6 HOMEWORK: Solve the following problems using dimensional analysis SHOW WORK! *Note: you need to find the molar mass of the substance if it is not provided 1 How many grams are in 45 moles of sodium fluoride, NaF? 2 How many moles are in 983 grams of aluminum hydroxide, Al(OH)3? 3 How many molecules are there in 450 grams of sodium sulfate, Na2SO4? 4 How many molecules are there in 315 grams of Na2SO4? 5 How many grams are there in 75 x molecules of sulfuric acid, H2SO4?

7 Mole Concept Activity Chemistry Name For all calculations, show your work clearly (with your conversion factors and units) Report your final answer using the proper number of significant figures and units! Circle/box your final answers Task 1: 1 Record the mass of the copper penny 2 Is this sample one mole of copper? Explain using the definition of molar mass (no calculations necessary here) 3 Approximately how many copper pennies would equal one mole of copper? Show work! 4 Determine the number of copper atoms in this penny Show work!

8 Task 2 1 Place an empty cup on the balance and zero the scale Add 1 drop of water to the cup Record the mass of water 2 Determine the number of moles of water in 1 drop of water Show work! 3 How many molecules of water are in 1 drop of water? Show work! Task 3: 1 Place an empty cup on the balance and zero the scale Add 1 spoonful of sugar to the cup Record the mass of sugar 2 Determine the number of sugar molecules in one spoonful of sugar