1.25.2011

Homework: journal pages 1-6





Today we started class by going over the lab from yesterday. We also went over the fact that to convert grams to moles ( or vice versa), you have to convert it to moles first. For example, if you wanted to find the number of molecules in 0.0908 grams of NiCl2 you need to go through at least to steps to solve. First you need to cancel out grams:


1 mole


0.0908 g x ---------


129.59 g





Then, you need to cancel out moles to find your final answer:


1 mole 6.02 x 10^23


0.0908 g x --------- x ------------


129.59 g 1 mole





This equals 4.22 x 10^20 molecules of NiCl2








Next Scriber: Cyril

Tuesday 9.7.10

Today, we started class with a lesson on how to find the volume and the density of an object. The density of an object is is its mass (in grams) divided by the objects volume. The objects volume can be found by measuring the length, width, and height, and then multiplying them together. We took notes on this lesson and recorded it in different hand outs.

An example of this formula is if the mass of a liquid is 35 grams and the volume is 7 mL, what is the density of the liquid?

The formula once again is D= 35 g/ 7 mL

You simply divide 35 by 7 and get 5 g/mL

We then started a lab to find the density and volume of a nail. We once again found the mass of the nail by weighing it and then using the displacement of water to help find the density. This method is done when an object is too small to be measured by a ruler. The object is dropped into a marked container filled with water, and the amount of water that is displaced is measured.