Chemistry SM-1131 Week 2 Lesson 2 Dr. Jesse Reich Assistant Professor of Chemistry Massachusetts Maritime Academy Fall 2008

Class Today Scavenger Hunt Review Quiz Answers Working with Density

The Hunt Ok, today we have to learn about density, but you’re going to learn about it on your own for a bit. You’re goal is the answer the following questions. When you are done ask for a quiz. When the quiz is done you are free to leave.

Hunt Objectives What is the equation for density. What is the density of water? What is the density of mercury metal? Oak wood? Birch wood? Ethanol? Gasoline? Diesel? Air? What happens when you put metal in water? Gasoline in water? Ethanol in water? What does the term miscible mean? What does it have to do with the last question?

Also Join Wikispaces Go to Click on get an account Fill out the form, but don’t get a wiki of your own. Check your Verify your account Go to reich-chemistry.wikispaces.com and click join space. Confirm with me that it all worked

Quiz 1 Significant Figures, how many Sig Figs does each of the following numbers have? 20,004, ,004, ,4445

Quiz 2 What is a hypothesis? How do experiments relate to hypothesizes? A theory. Something used to test theory. Good experiments only have 1 variable that are tested.

Quiz Q3 Convert the following numbers into scientific notation 20,004, e7 20,004, e e e-4 52,0005.2e4

Quiz Q4 Round the following numbers to the third sig fig. 20,004,00020,000, ,27052,300

Quiz Q5 Add the following numbers, round, and put into scientific notation. 5, , ,575 = 1.0e = 2.6e2 12, , ,0002e e1 2.3e e e43.16e5

Quiz Q6 Multiply the following numbers, round, and put into scientific notation * 15.2 / 12 =5.5e1 20,202 / 2,000 * 1,525 = 2e * 15.2 / e * * e-7

Quiz Q 7-8 Convert 1,500 inches into feet. (I don’t care about the number copy the form) 1,500 in * 1ft = 125ft 12 inches Convert 162 ft into yards. (I want to see the form!) 162 ft * 1 yd = 54.0 yards 3 ft

Quiz Q 9 Convert 2,220 inches into yards 2220 in * 1 ft * 1yd = => 12 in 3ft 61.7 => 6.17e1

Quiz Q10 50,000g into kg 50,000g * 1kg = 50kg 1000 g 4,300 km into m 4,300 km * 1,000m = 4,300,000m 1 km

Quiz Q L into ml 2.2L x 1,000 mL = 2,200mL 1 L 120 cm into inches 120 cm * 1 in = cm

Quiz Q10 Convert 2,500,542 seconds into years 2,500,542 sec * 1 min * 1 hr * 1 day * 1 year = 60 sec 60 min 24 hr 365 days = years = years = e-2

Density Density = Mass volume d = m v

Let’s calculate density I have a ball of metal that takes up 3ml and weighs 12.6g. What is it’s density? d = m v d= 12.6g= 4.2 g/ml, but 3ml only has 1 sig fig 3ml OK so, finally 4 g/ml would be the answer!

Let’s use density In lab I draw out 15ml of a liquid that has 1.67 g/ml. How much mass does it have? (copy the given, and use the density) 15ml * 1.67 g = 25.05g ml

Let’s use density… Again A recipe calls for 200.ml of ethanol, which has a density of 0.789g/ml. How many grams did we add? 200. ml ethanol* g ethanol= ethanol ml 158g => 1.58g e2

Time Left OK, we’re going to work on Wikis This only works if you have signed in 1 open up the web page 2 click on the atomic history wiki-timeline link 3 click on your class 4 click edit this page Type in: Fall.2008.MMA.lastname1.lastname2.timeline

Making a link Highlight the text you just wrote Click on the icon in the top bar that has a chain in it. Click ok when the pop up comes Click Save If you do something bad like erase someone else’s don’t save what you did. Just hit cancel.

Once you make a link Click on your link Hit edit this page Type in John Dalton looks like D. Reich Hit Save Notice how all the computers in the world can now see that John Dalton looks like D. Reich You’re going to make your wiki like this. Be sure to save often!