• When you come in: Get a copy of Lab Report 1 and Lab Report 2 from the front table. Read through them. – Which one is better? Why?– What are some specific examples of good/bad things in

either lab report?

• Finish Notes: Two-Step Conversions• The How-To’s of Lab Reports• The Gum Lab

February 26, 2014

• Earn back up to 50% of the points you missed• Example: 30/60 (Original score) 50% Rework problems and earn 25 points 25 x 50% = 13 points 30 + 15 = 45/60 45/55 (Revised score) 82%

• MC: Change answer on scantron, I will rescore• FR: Re-do problem in different colored pen/pencil. • EXCR: Not available on corrections.

Due March 13

Test Corrections

moles

Molar Conversions: 2 steps

Mass in grams

Number of particles

Divide by the molar mass then multiply by Avogadro’s #

Divide by Avogadro’s # then multiply by the molar mass

• Start with: grams• End with: formula units (particles)• Math: divide by molar mass, then multiply by Avogadro’s

number• Molar mass NaCl: 22.990 + 35.453 = 58.443

• 3.0 g x 6.02 x 1023 molecules= 3.09 x 1022 f. units 58.443 g/mol

• Calculator Help: Use the EE button • 6.02 x 1023 = 6.02EE23

Example: How many formula units are in 3.0 g NaCl?

• Start with: molecules (particles)• End with: grams• Math: divide by Avogadro’s number, then multiply by

molar mass• Molar mass NH3: 14.007 + 3(1.0079) = 17.0307

• 3.5 x 1024 x 17.0307 g/mol= 99.016 g 6.02 x 1023

• Calculator Help: Use the EE button • 6.02 x 1023 = 6.02EE23

Example: How many grams are in 3.5 x 1024 molecules NH3?

• Which one is better? Why?

Back to the Lab Reports

• In lab reports, use the PASSIVE VOICE.

• Active: I ate the apple.

• Passive: The apple was eaten.

• How to check: Can it be done “by zombies”?

Passive v. Active Voice

• The apple was eaten… by zombies!

• The compound was heated to a temperature of 20 degrees Celcius.

• The compound was heated by zombies. YEP.

• My partner heated the compound to 20 degrees.

• My partner heated the compound by zombies. NOPE.

Passive Voice

• Object(s) + was + _________ed/en ……eatenheatedaddedmeasuredweighedetc.

Write your own!