Chemistry Honors – Class 27

Dates

• Periods A, C – Tuesday, October 22nd
• Period D – Thursday, October 24th
• NOTE: No sophomore classes on Wednesday, October 23rd

Review Homework

• volunteers at the board
• How do I know which elements are paired? (diatomic)
• NOFAT7 identification = diatomic elements
  • N, O, F, Cl, Br, I, At
  • Hydrogen
  • In pairs when alone natural state
  • does not apply to compounds

How do I show that matter is conserved in a reaction?

• Balancing is an iterative process – keep trying
• Only change coefficient
• coefficients apply to the whole formula
• don’t change formulas
• Best way to learn is by practicing

Strategies

• first balance elements that appear in only one compound on each side
• then proceed to go back and forth, checking and double-checking
• write a number in front of each, including the “1”
• underline the coefficients at the end

In-Class Work

• Chapter 6 problem 38
• be sure and leave room for writing changing answers
• using PENCIL helps – you can erase!

Homework

• Chapter 6 (41)
• Quiz on writing and balancing reactions on Friday for all sections