1/21/2013
NO SCHOOL - MLK DAY
1/22/2013 Standards: 3 (Stoichiometry)
Objectives:
● be able to: mol <---> mass (compounds)
DO NOW:
1. Convert 4.100 mol KMnO4 to grams of KMnO4
(check ans = 647.8 g). If correct, start homework.
HOMEWORK:
1. Ch 11.3, p. 323 - 324 27-29, and 30 (a-e). Show all calculations. All
problems require 2 fractions, including given/1. Check you work,
answer will be on today's HW page. (5 pts) Std 3.
==========================================================
BASKET: Journal 1/18 (Molar Mass Lab)
1. Ch 11.3 p. 321 20-24, and p. 322 25-26 (5 pts) Std 3
When done, turn over
ans sheet and quiz
DO NOW
Convert 4.100 mol KMnO4 to grams of KMnO4
1/23/2013 Standards: 3 (Stoichiometry)
Objectives:
● be able to: mass <---> mol <---> particles
(compounds)
DO NOW:
1. Convert 85.0 g KMnO4 to particles of KMnO4 . Requires 3 fractions
including the given/1.
HOMEWORK:
1. Ch 11.3, p. 326 31-35. Show all calculations and label each section of each problem. (5 pts) Std 3
==========================================================
BASKET:
1. Ch 11.3, p. 326 31-35. Show all calculations. All problems
require 3 fractions, including given/1. (5 pts) Std 3
ANNOUNCEMENT
Look at your on-line grade and your Stamp Sheet and compare to my on-line stamp
sheet. If you have anything missing, you have until Friday to make-up or receive a
note home to parents.
DO NOW
1. Convert 85.0 g KMnO4 to particles of KMnO4
p. 326 #31
Ag2CrO4 THE SOLID
look below
Ag
O
O
Cr
O
O
Ag
ZERO CHARGE
look below
Demo - AgNO3
mix with NaCl
IN SOLUTION
Particles in this problem are:
CrO42- ION
Ag1+
O
O
Ag1+
O
O
Cr
p. 326 #31
O
O
A
O
C
A g
r
g
O
Solution:
first convert 25.8 g Ag2CrO4 to particles (molecules Ag2CrO4 ). You cannot answer a, b, and c until you
have done this conversion.
25.8 g Ag2CrO4
1 mol Ag2CrO4
6.02 x 1023 Ag2CrO4
----------------------- x ---------------------- x ----------------------------1
332 g Ag2CrO4
1 mol Ag2CrO4
= 0.468 x 1023 = 4.68 x 1022 Ag2CrO4
a. convert particles of Ag2CrO4 to particles of Ag1+ ions.
ratio of Ag2CrO4 : Ag1+ ions is: 2 Ag1+ : 1 Ag2CrO4
Use this ratio to convert Ag2CrO4 particles (answer to first part of solution)
4.68 x 1022 Ag2CrO4
2 Ag1+
x
1 Ag2CrO4
1
=
9.36 Ag1+ ions
b. convert particles of Ag2CrO4 to particles of CrO42- ions.
ratio of Ag2CrO4 : CrO42- ions is: 1 CrO42- : 1 Ag2CrO4
Use this ratio to convert Ag2CrO4 molecules (answer to first part of solution)
to CrO42- ions
4.68 x 1022 Ag2CrO4
1 CrO42x
1 Ag2CrO4
1
=
4.68 X 1022 CrO42- ions
c. Finding the grams of one Ag2CrO4 molecule means the grams/formula
unit of Ag2CrO4 . That is the molar mass of Ag2CrO4 divided by
the Avo number.
332 g Ag2CrO4
1 mol Ag2CrO4
x
1 mol Ag2CrO4
6.02 x 1023 Ag2CrO4
=
5.51 x 10-22 g/formula unit
Ag2CrO4
1/24/2013 Standards: 3 (Stoichiometry)
Objectives:
● be able to calculate: mass <---> mol <---> particles
(compounds)
DO NOW:
1. Complete Worksheet on mass <---> mol <---> particles
HOMEWORK:
1. App A, p. 876-877, Ch 11.3 15-24 (5 pts) Std 3
==========================================================
BASKET (Turned In):
1. Ch 11.3, p. 326 31-35. Show all calculations and label each section of each problem. (5 pts) Std 3
ANNOUNCEMENTS
Practice quiz (10 pts) on Friday 1/25 and
Periods 1 & 2 notebooks to be collected Friday 1/25.
Answers to tonight's HW so you can check your answers.
Ch 11.3, App A, p. 876 15-24
1/25/2013 Standards: 3 (Stoichiometry)
Objectives:
● Review: mass <---> mol <---> particles
(compounds)
● Mini-Quiz Ch 11.1-11.3 (10 pts)
DO NOW:
1. Turn in HW and take a blank piece of paper.
HOMEWORK:
1. App A, p. 876-877, Ch 11.3 15-24 (5 pts) Std 3 (Yes, DO IT AGAIN)
If you do not have a text book, you will find the problems on the next
page of this Whiteboard file.
==========================================================
BASKET (Turned In): Journal 1/23 (2 days ago)
1. App A, p. 876-877, Ch 11.3 15-24 (5 pts) Std 3
Notebooks collected for Periods 1 & 2 Fri 1/25
Periods 3
Mon 1/28
Periods 5 & 6 Tu 1/29
Students were ill prepared for this quiz.
App A, p. 876-877, Ch 11.3 15-24 (5 pts) Std 3
2 students - one move arrows, one dictates set-up
Given
Find
FI ND
GIV EN
Formula of a Hydrate
moles of H2O
moles of dry salt
HYDRATES
Chemicals that adsorb water.
Dried out hydrates will get "wet" if left out in an unsealed container.
They will even get "wet" in a "closed" container if left long enough.
Example of hydrate Calculations
BaCl2 • 2 H2O
Getting the moles of H2O
Mass of evaporating dish = 15.9 g
Mass of dish and hydrated salt = 400.0
Mass of hydrated salt 400.0 g
Mass of dry salt 368