Transcript Molar mass
Catalyst 1. How many particles are in one mole? 2. How many hours are there in 362 minutes 3. How many minutes are in 2 years? (1 year = 365 days; 1 day=24 h; 1 h=60 min) End Puppies! • You have 5 white dogs that weigh 15 pounds, 3 brown dogs that weigh 10 pounds, and 1 black dog that weighs 20 pounds. How much do all the dogs weigh together? Lecture 3.5 – Molar Mass and Gram to Moles Conversion Today’s Learning Targets • LT 3.7 – I can calculate the molar mass of given element or compound. • LT 3.8 – Given an element, I can convert between the number of moles to grams and grams back to moles What is molar mass? I. Molar Mass • Molar mass is the mass, in grams, of 1 mole of substance. (the mass of 6.02 x 1023 particles of a substance) • The molar mass is the mass listed on the periodic table • Units of Molar mass are g/mol Molar Mass How do we calculate molar mass? More Tables! Element Number of Molar Mass Total Total Molar Atoms in Element Mass Compound Molar Mass x = x = x = Class Examples • CaBr2 • Ca3(PO4)2 Table Talk • Calculate the molar mass for the following compounds: – KCN – Ca(NO3)2 – Al2(SO4)3 BINGO • Take out a sheet of paper and make a 4 x 4 grid by folding the paper in half 4 times. • Write the following terms/numbers on the sheet: 74 98 g/mol 75 122 Molar Mass g 56 37 Atomic Mass mol 97 36 99 55 123 Questions 1. The mass, in grams, of 1 mole of substance 2. This is the molar mass for an element on the Periodic Table 3. This is the units for molar mass 4. Calculate the molar mass for H2SO4 5. Calculate the molar mass for Ca(OH)2 6. Calculate the molar mass for AlPO4 7. Calculate the molar mass for HCl 8. Calculate the molar mass for MgO2 How many moles of chalk does it take to write your name? How do we convert between moles and grams? Our Focus for Today Grams of Substance A How do we go from grams to moles? Moles A Particles of A I. Converting from Grams to Moles & Back • It is possible to convert between grams and moles of a substance. • We accomplish this conversion using the same tools of dimensional analysis II. OUR CONVERSION FACTOR FOR GOING BETWEEN GRAMS AND MOLES… III. Using the Conversion Factor When converting from grams to moles you must DIVIDE by the molar mass 1 mole Grams Moles Molar Mass When converting from moles to grams you must MULTIPLY by the molar mass Molar Mass Moles 1 mol Grams Class Example • If you react 360 g of C6H12O6 how many moles of C6H12O6 did you react in this reaction? Table Talk • If you start with 36 g of H2O, then how many moles of H2O do you react? Class Example • If we place 15 moles of NaN3 how many grams of NaN3 do you have before the reaction? Class Example • If we place 26 moles of MgCl2 how many grams of MgCl2 do you have before the reaction? Coach and Correct • Pair up with the person across from you. • Pick a person to be Partner A and a person to be Partner B. • For the first question Partner A is the coach and Partner B is the writer. Question 1 • You react 7 moles of HCl how many grams of HCl do you have? Question 2 • You have 4 moles of CS2 how many grams of CS2 do you have? Question 3 • You have 500 g of NH3. How many moles of NH3 do you have? Question 4 You start with 7 moles of KClO3, how many grams did you begin the reaction with? Question 5 • You have 52 g of N2 how many moles N2 will you have Closing Time • Homework 3.5