Class Notes (921,787)
CA (542,639)
UNB (368)
CHEM (47)
CHEM1006 (24)
Lecture 2

# CHEM1006 Lecture 2: Chem2_2

2 Pages
30 Views

Department
Chemistry
Course Code
CHEM1006
Professor
Reeves Valerie

This preview shows half of the first page. Sign up to view the full 2 pages of the document.
Lecture 2
Unit analysis is a form of proportional reasoning where a given measurement can be multiplied
by a known proportion or ratio to give a result having a different unit or dimension.
Algebraically, we know that any number multiplied by one will be unchanged.
If the number has units, and we multiply it by a ratio containing units, the units in the number
will multiply and divide by the units of the ratio, giving the original number but with different
units.
This method can be generalized as: multiply or divide a given number by a known ratio to find
The ratios used are based upon the units and are set up so that the units in the denominator of
the ratio match the numerator units of the given and the units in the numerator of the ratio
match those in either the next ratio or the final answer.
When these are multiplied, the given number will now have the correct units for your answer.
Say you were trying to convert 3.41 grams of He to a number of atoms of He. You would
identify 3.41 grams as the given.
The first step is always to place the given out front of your equation.
Then find a ratio that will help you convert the units of grams to atoms.
As you probably have already guessed, you need to use a couple of ratios to help you in this
problem.
The ratio that 4.002 g of He = 1 mole will help you in this problem.
Then you set up your ratios so that your units will cancel successfully.
As always, your final answer should contain the correct number of sig figs and the correct units.
If you had a sample of a substance with a mass of 0.0034 grams, and you wanted to express
that mass in mg, you could use the following dimensional analysis.
The given quantity is the mass of 0.0034 grams.
find more resources at oneclass.com
find more resources at oneclass.com

#### Loved by over 2.2 million students

Over 90% improved by at least one letter grade.

OneClass has been such a huge help in my studies at UofT especially since I am a transfer student. OneClass is the study buddy I never had before and definitely gives me the extra push to get from a B to an A!

Leah â€” University of Toronto

Balancing social life With academics can be difficult, that is why I'm so glad that OneClass is out there where I can find the top notes for all of my classes. Now I can be the all-star student I want to be.

Saarim â€” University of Michigan

As a college student living on a college budget, I love how easy it is to earn gift cards just by submitting my notes.

Jenna â€” University of Wisconsin

OneClass has allowed me to catch up with my most difficult course! #lifesaver

Anne â€” University of California
Description
Lecture 2 Unit analysis is a form of proportional reasoning where a given measurement can be multiplied by a known proportion or ratio to give a result having a different unit or dimension. Algebraically, we know that any number multiplied by one will be unchanged. If the number has units, and we multiply it by a ratio containing units, the units in the number will multiply and divide by the units of the ratio, giving the original number but with different units. This method can be generalized as: multiply or divide a given number by a known ratio to find your answer. The ratios used are based upon the units and are set up so that the units in the denominator of the ratio match the numerator units of the given and the units in the numerator of the ratio match those in either the next ratio or the final answer. When these are multiplied, the given number will now have the correct units for your answer. Say you were trying to convert 3.41 grams of He to a number of atoms of He. You would identify
More Less

Only half of the first page are available for preview. Some parts have been intentionally blurred.

Unlock Document

Unlock to view full version

Unlock Document
Notes
Practice
Earn
Me

OR

Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Join to view

OR

By registering, I agree to the Terms and Privacy Policies
Just a few more details

So we can recommend you notes for your school.