Dimensional Analysis

Yesterday we learned about dimensional analysis. Dimensional analysis is used to convert one quantity into a different quantity. Below is an example:


 The quantity given was 10 m/s and they wanted to know what that quantity would be if it were converted into km/hr. Notice that the same units are placed diagonally from each other, so they cancel out each other when multiplied.

Using cubed and square unit is a similar process, just a little more complicated. For example, we are going to convert 56 in^3 to cm^3.

56 in^3 x (2.54cm/1in)^3 = 920 cm^3

Quiz Disappointments

Over the weekend, I reviewed the material in order to prepare for the quiz Monday. I was feeling pretty good and I feel like I had a decent understanding of what significant figures are, which was the hardest part of the unit so far for me. During the quiz, I felt like I knew what I was doing and felt like I would get an okay grade. When I checked the grade book, unfortunately, the grade was lower than I expected. At least it was a quiz and not the unit test, which is tomorrow, so the 5 points I missed should not tank my grade in the long run.

Significant Figures

The hardest lesson so far in this unit is significant figures. The definition of a significant figure is "each of the digits of a number that are used to express it to the required degree of accuracy, starting from the first nonzero digit". During the notes, I became very confused because there was a lot of information coming at once, so I did not have much time to process and understand it, but after looking at some different websites, I feel like I understand a little better. Below are some links that I feel like helped me understand what significant figures are and how to determine the number of significant figures in a number a little better.

• Websites:
• Significant Figure Rules
• Significant Figure Rules and How to do Math with Significant Figures
• Videos:
• Multiplying and Dividing with Significant Figures
• Adding and Subtracting Significant Figures

Quiz Yourself Here!

National Mole Day!

This past Friday was National Mole Day, so we had a party during class to celebrate. Since we all had a lot of room for creativity in our theme for our mole, they were all very different from each other. It was interesting to see how other people did completely different things even though we had the same instructions for our project. The connection with chemistry is that although a mole is an animal, it is also a type of measurement used in chemistry. It is expressed as 6.0221415 x 10^23. 

The history of Mole Day is explained here: Mole Day History