130 likes | 224 Views
Way Back Wednesday!. What is the difference between an ionic and covalent bond? Name one element in the family of the halogens . Which of these is a nonmetal: K, Ni, As, Cl ?. You must be silent and working for credit B e on time E nter silently G rab papers I mmediately start work
E N D
Way Back Wednesday! • What is the difference between an ionic and covalent bond? • Name one element in the family of the halogens. • Which of these is a nonmetal: K, Ni, As, Cl? You must be silent and working for credit Be on time Enter silently Grab papers Immediately start work No talking I still need parent letters from a lot of people – get that to me by the end of this week
Announcements Parent letter – I need yours! Grades will be updated on the evening of Sunday, January 16th, not beforehand Quizzes must be made up with me by next Tuesday, January 18th (extended due to snow day)
THE MOOOOOOOOOLE! The mole: Time: 10 minutes
Key Point #1: A mole is a word used to represent 6.02 x 1023 atoms/particles/molecules of a substance. No matter what compound we’re talking about, a mole is always 6.02 x 1023. It is a word just like “dozen”. I can have a dozen eggs, a dozen roses, or a dozen bagels and I’m still talk about having 12 of each substance.
Key Point #2: We use 1 mol = 6.02 x 1023 as a conversion factor (like we learned about last week) in dimensional analysis.
Dimensional analysis will still work the same way, but we are introducing a new conversion factor. • Draw a great big T • Write down the number the problem gives you in the top left of this T • Put the unit of that number in the bottom right part of the T • Write the unit that you want in the top right corner of the T • Write the conversion factor in front of the units from steps 3 and 4 • Multiply everything on the top and divide it by everything on the bottom
Example How many atoms are in 1.2 moles of BeBr2?
GuidedPractice • How many atoms are in the quantities below? • Walk me through the problems • 1.25moles • .5 moles
Independent Practice Answer the following questions on a separate piece of paper: How many atoms does 2.0 moles of He represent? How many atoms are in are in 3.0 moles of NaCl? How many atoms are in 0.25 moles of CH4? How many total atoms are in 1.0 moles of H2O ? How many atoms are in 1.5 moles of BeBr2? How many atoms are in .75 moles?
Exit Ticket (5 minutes) 1. What number does a mole of something represent? 2. Do a mole of copper and a mole of oxygen have the same number of atoms? 3. If Rodnerius has 3.5 moles of copper, how many atoms of copper does he have?