Lab Equipment

Choose a Study ModeScatterLearnFlashcards

Study these flash cards | Study chemistry flash cards

Homework Help Gas Collection Problems

Consider the following problem:

A 500 mL sample of oxygen was collected over water at 23°C and 760 torr pressure. What volume will the dry oxygen occupy at 23°C and 760 torr? The vapor pressure of water at 23°C is 21.1 torr.

What are we solving for? V2  

Plan:   1 - Use Dalton's Law to find P02 

                2 - Use Combined Gas Law to solve for V2 

P_TOTAL = P_OXYGEN - P_WATER

P_OXYGEN = 760 torr – 21.1 torr

P_OXYGEN = 738.9 torr 

Given: V₁ = 500 mL          V₂ = ?               (No change in T)

                  P₁ = 738.9 torr         P₂ = 760 torr

V₂ = P₁V₁ T₂       (Temperature can cancel as there is no change.)

                P₂ T₁

   

V₂ = (500 mL) (739 torr) = 486 mL dry O₂

                         (760 torr)

Test Hints

Friday's test will have 25 or so multiple choice, 8-10 problems you have to show work for AND two questions that require written explanations.

Things to do to make sure you are ready for the FRIDAY's test:

• (5 min.) Click on the density of a gas link and follow along.
• (5 min.) Check that you have memorized Avogadro's number, STP values, R and can match units to their quantity (ex. atm is a unit of pressure.)
• (10-20 min) Study terms at quizlet. Take a test.
• (10-45 min) Visit sciencegeek.net and try the phase diagrams and Ideal Gas Law. See the extra practice tab for more if you have time. This is a low risk test like situation (IDEAL WAY TO STUDY!)
• Try the multiple choice Questions for Review. 
• Study practice test 2.

We will discuss phase diagrams and changes between states of matter this week as well as solving problems from about water displacement.  Depending on your success with this material we can add a lab to the mix this week.  On Wednesday we are visiting the computer lab to do some practice test questions.  Please do bring your book and notebook so that you can refer to your notes as you work.

YOUR HARD WORK WILL PAY OFF. Plan some time for homecoming fun but keep some time every day for chemistry. Hard work now will keep paying off as we cover new topics. 

Homework Help

Done your reveiw homework yet?   The relevant links are below.  Remember I need proof that you practiced until you scored a 90% or better on each one you choose. Please choose the KMT link if you missed the questions with the flask pictures.
Calculations of Formula Mass
Formulas: potassium oxide K2O - manganese(v)oxide  MnO2 - sodium fluoride NaF - calcium bromide CaBr2
thulium III oxide - Tm2O3 - calcium nitride Ca3N2 
Formula Mass and Gram/Mole/Volume Conversions
Temperature and Pressure Conversions
Kinetic Molecular Theory

Want to email me with the screen shots? Email Mrs.Chambers  Use the print screen button and then open and email and paste the shot. You can email can review score or see one with lots of shots.

BTW - You can do all your calculations on your calculator for this online practice, but you can't do that test day.  Why not try writing out a couple?

Beakman's World

This is a funny show and it's about gases.  Hope you enjoy!

We think..

Here are the results by class of the we think activity.  Remember the bottle started out flexible and then grew harder to squeeze as the fizz keeper was pumped. If we opened the cap it sounded like a new soda bottle had just been opened.
3rd period - Pressure increased. Most think volume remained the same and that temperature did too. (A few think temp changed and increased.) The number of moles increased.
4th period - Pressure was increased. Volume is split between increasing and staying the same. One group votes for temperature increasing and number of moles increasing while one says these stay the same.

7th period - Pressure was increased. This is the only one we agree one, but most students think number of moles increased. For volume and temperature some think increase and some that it didn't change.

What do you think now?

SHS students read from First Circle

On Tuesday, September 20, 2011, at 6:00 P.M., the Hub City Bookshop downtown on Morgan Square will host a reading of poetry, short fiction, and creative nonfiction by writers from Spartanburg High School who had work published in the 2011 edition of First Circle, the school's award-winning literary magazine. As many of you know, our students have won statewide first-place awards for their writing in each of the last three years, so this will be a good opportunity for everyone to see what the excitement's all about. The reading is free and open to the public.