LAB 2E!!

Hey

Last class, we did a lab from Essential Experiments for Chemistry!!

We are going to go over what we did.

Our Purpose was to use scienticfic notation and significant figures after determining both volume & density  
                            of an Aluminum sheet.

We measured the length and the width and the mass of the sheet. Then we figured out the density.

Follow up Questions

1. A rectangular metal tray (22.55cm by 15.33cm) plated with thin layerof gold (density: 19.32g/cm3).
Gold plating mass : 0.0538g. Calculate the thinkness using scientific notation and number of sig. figs.

First, write the general formula of density.

                          D =     m   
                                     V

Then plug in numbers.

                  19.32g/cm3 =   0.0538g   
                                              V
                   
                               V    =   0.0538g     
                                           19.32g/cm3

                                 V  =   2.78 x 10-3cm3

Calculate thickness or height

                         V = LWH
                 
                 2.78 x 10-3 = 22.55(15.33)H

                          H =   2.78 x 10-3
                                   22.55(15.33)

                       H = 8.06 x 10-6cm

2. 1000.0cm3 of oil. Surface area = 850.0m2. Density: 0.850g/cm3
    How thick was the oil?

Ok, first there is some irrelevant info here.

Density info is not need because we need to find height or thickness

Therefore, write equation for volume.

                   V = LWH

Dont forget to convert m to cm

                1000.0 = 8.50 x 106(H)

                    H =  8.50 x 106  
                             1000.0

                   H = 1.76 x 10-6cm

Thats it for today!

Good nite!

Written by JK Nov 4,2010