Monday, August 24, 2015

What is a mole? And what does it have to do with Chemistry?

Moles are used to count atoms. There are 22,000,000,000,000,000,000 quintillion atoms in a grain of sand and even counting grains of sand is a pain. Because atoms are so tiny, we use the mole to estimate.

There are 6.02 x 10 ^23 molecules in one mole. That's a whole lot. This is our new favorite number because it needs to be memorized. We will practice converting from moles to molecules.

Next we discussed molar mass. Molar mass = 1 mole and it also equals atomic mass from the periodic table. To find the molar mass of carbon dioxide you find the mass of carbon and two oxygens and add them together. Finding molar mass is not difficult unless the molecule has tricky subscripts (which we have been practicing).

The third thing about moles is that "one mole of any gas will occupy 22.4 Liters." 22.4 is another favorite number. We can convert from moles to liters and from liters to moles. 

Just how big is a mole? There's a TedEd talk on that! Watch it here!

Friday, August 21, 2015

Percent Composition and Bubble Gum

Percent composition is just like determining your grade - the amount you got divided by the the whole amount. 

With compounds, you find the mass of a particular element and divide it by the mass of the whole compound. So if you wanted to know the percent composition of oxygen in water, you would take the mass of oxygen and divide it by the mass of water. 

We practiced some basics and the students measured the amount of sugar found in DubbleBubble bubble gum. 

Students each had a piece of gum and observed the gum by weighing it, drawing it, and smelling it. The students chewed the gum for ten minutes. While they were waiting we watched How Its Made on bubblegum.

After ten minutes, students did more observations and re-weighed the gum. The gum weighed less... why? Because the sugar dissolved and was lost. Using this weight difference, students determined the percent composition of sugar in the gum they chewed. They also can convert the grams to moles and determine how many moles of sugar were in the gum.

Conversions (Dimensional Analysis)

Conversions, or dimensional analysis, are used to change one unit to another. This is really useful when converting to metric units, but is essential to chemistry in terms of mole conversions. Setting up conversions is a skill so we started with learning the format. There are plenty of how to videos out there on the internet for anyone needing a tutorial.

We practiced conversions with some of the crazy things people do to get in the Guinness Book of World Records - like longest ear hair, skinniest waist, tallest man, etc. I think the one the kids thought was the weirdest was the lady who can pop her eyes out 12mm.

Check out more crazy records here!

Thursday, August 20, 2015

Expanding Horizons 1

Each week you will be asked to visit a few online sources. You may be asked to read an article, watch a video, play a game, take a quiz, listen to a podcast or all of the above. Sometimes you will be given specific questions to answer. At other times you will be asked to write a summary convincing others that they should check out what you found. These assignments will take time so do not wait until the last minute. At all websites, you will be asked to correctly write a citation.

Assignments will be given on Thursday and are due by the end of the school day on the following Thursday. If you are absent, the assignment is due the day you return. 

This week is the first week!

Video 1

How the Elements Got Their Names
You may need to watch this video more than once and pause it.

Video 2 

“From Outer Space to Under Our Skin: A Look At The Universe”                    
This video is old, but interesting to think about. Note 100 = 1.

Please let MsJ know as soon as possible if you have problems or questions. 

Video Citation
Last Name, First initial. Middle initial. [Username if no real name is given (still last name, first name)]. (Year, Month Date). Title of video(in italics). [Video File]. Retrieved from URL. 

Typed Video Example:
AsapSCIENCE. (2015, March 15). What Happens If All The Bees Die? [Video File].