Percent Composition

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 began a paper forensics investigation that is using percent composition to determine which passengers in a plane crash are which, which passenger is responsible for the plane crash, and more. 

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!

Next week we will be learning how to do conversions with moles!

Hazard Diamonds - Safety at a glance!

NFPA Hazard Diamonds

The NFPA 704 fire diamond (or hazmat diamond) is described in NFPA Standard 704, maintained by the National Fire Protection Association. The system identifies four key hazards (health (blue), flammability (red), instability (yellow), and special (white)) and their degree of severity. Hazard severity is rated numerically, ranging from 0 (minimal) to 4 (severe).

The hazard diamond is useful because it allows emergency personnel to quickly and easily identify the risks posed by hazardous materials and is  useful to determine what, if any, special equipment should be used, procedures followed, or precautions taken during an emergency response. (Summarized & more information here.)

Want to make your own customizable hazard diamond? Click here. Why does this feature exist? So people can make easily identifiable hazard diamonds for any chemical they have on hand. 

Fall 2012 - Welcome Back!

Greetings students, parents, and guardians.

Welcome to a new school year with Ms Jancaitis! This blog has been set up to connect students, parents, and guardians with the chemistry class.

 At Open House or in class, each student will receive a course syllabus. The course syllabus outlines what the course will be like, what topics will be covered, and course expectations. It also contains contact information. There will be a quiz on this syllabus on Thursday.

Our first unit will cover lab safety and equipment. Each note packet comes with the safety rules and contract. The safety rules and contract need to be read and signed by both the student and parent guardian. The safety rules are rules designed to keep the classroom safe and orderly to maximize learning and prevent accidents and injuries. These rules need to be studied because there will be a safety test on Monday or Tuesday and infractions of these rules can lead to disciplinary action as well as low assignment grades. A contract holds students accountable for the items that are broken if the student is acting a manner that is unsafe for themselves or those around them.


Please have these papers signed and returned by Monday the 20th. Students not returning signed safety rules and safety contracts will not be able to participate in labs and activities until the contracts are signed and returned.