Warm-up (Sept 19 and 20) Find your new seats! Please get out a pencil and keep everything else away.

Image: http://morrisonlabs.com/lab_safety.htm What’s wrong? In your groups, identify 6 different safety concerns shown in the picture below. Image: http://morrisonlabs.com/lab_safety.htm

The answers are … Don’t fool around during a lab. Always wear safety goggles when doing an experiment and DON’T EVER SIT Always point test tubes and other items away from yourself and others when heating. Don’t eat or drink while in the lab. Keep hair and other flammable objects away from flames. Don’t leave a flame unattended. Image: http://morrisonlabs.com/lab_safety.htm

Safety Quiz Time! When you are done, please raise your hand and I will come get the quiz.

Sig Figs Help! We are having some serious trouble still with Sig Figs! See extra practice folder on Moodle and HW 3 and HW 4 keys Also Khan Academy videos linked on Moodle – USE YOUR RESOURCES Come see me today at lunch (T or Th)! Quiz in two classes on Sig Figs and elements!

Density: an intensive physical property Density (ρ) = mass (g) volume (mL or cm3 or cc) Which is more dense? Hammers (the mass is more compact into a smaller volume) 10 kg of feathers? OR 10 kg of hammers?

Calculations in Chemistry! Required Format For All Lab Calculations: LABEL, SHOW EQUATION, SHOW MATH Label: Show Formula: Show work: (sig figs and units!) Density example in notes

Calculations in Chemistry! (A finished example for you) Required Format Reminder: LABEL, SHOW EQUATION, SHOW MATH Total mass of two washers Formula: Total mass of washer = Washer 1 + Washer 2 Show work: Total mass = 32.56 g + 31.42 g = 63.98 g

How can we measure density in lab? Of a box? Of a hammer? BOX. Ruler and balance Hammer: Balance, but ruler doesn’t work for oddly shaped object! You have to use volume displacement!

Volume Displacement A way to measure odd-shaped items in lab using water and a graduated cylinder! What will be the data you need for this calculation? What will be the formula for this calculation?

Measurement 101 How long is the apple in centimeters? 6.4-6.6 cm

Measurement 101 How much liquid is in the graduated cylinder in mL?

Set up Lab book Table of Contents!

Lab #1 – Density (Part 1) – 20 min READ the handout carefully NOW Three trials of each cylinder Test one NUMBER and one LETTER Be good scientists!! What is the correct data table to have for this lab (on boards)?? Part 1 Calculations DUE: Next class! Hand written in Lab books, using proper format we learned today. Give 5 min to read, then do data table together in lab books

Homework Day 6 Sig Figs and periodic table quiz 2 M/T Part 1 Calculations DUE: Next class! Hand written in Lab books, using proper format we learned today.