Agenda and Homework for September 21

Do Now:
Please consider this released STAR test question:

Generally, how do atomic masses vary throughout the periodic table of the elements?

1. They increase from left to right and top to bottom.
2. They increase from left to right and bottom to top.
3. They increase from right to left and top to bottom.
4. They increase from right to left and bottom to top.

Announcement:

There will be a Unit 1 Quiz on Thursday. The quiz will contain materials from Chapters 1-4, as well as any other topics covered in class, such as questions from Einstein's Big Idea.

Agenda

1. Do Now
2. Review of Homework quiz
3. Review of density cube activity
4. Discussion of online grade posting
5. Homework review

Homework

p. 97 #79, 82, 84, 87, 90.

Homework for 9-17-2010

Galileo Thermometer

Do Now
Please consider this released STAR test question:

Why is cobalt (Co) placed before nickel (Ni) on the periodic table of the elements even though it has a higher average atomic mass than nickel?

1. Nickel has one more proton
2. Cobalt was discovered first.
   
3. Nickel has fewer electrons.
   
4. Cobalt has a lower density.
   

Agenda for 9-17 

1. 1. 1. Do Now
      2. Quickie Quiz discussion
      3. Safety Quiz results 
      4. Homework review 
      5. Homework quiz (open notes)
      6. Head start on weekend homework (time permitting)

1. 
   
   
   

   
   
   
   

   Homework assignment
   pg 96, #58, 59, 62, 65,  66, 70, 72
   

   
   
   
   

   Please do the following problems off of this worksheet:
   
   
   1. Why are numbers used in chemistry often expressed in scientific notation?

   
   

   2. Circle the letter of each sentence that is true about numbers expressed in

   scientific notation.

   • a.   A number expressed in scientific notation is written as the product of a coefficient and a power of 10.
   • b.   The power of 10 is called the exponent.
   • c.   The coefficient is always a number greater than or equal to one and less than ten.
   • d.   For numbers less than one, the exponent is positive.

   
   
   

   3. Circle the letter of the answer in which 503,000,000 is written correctly in

   scientific notation.

   • a. 5.03  10^–7
   • b. 503  10⁶
   • c. 5.03  10⁸
   • d. 503 million

   
   
   

   Accuracy, Precision, and Error (pages 64–65)

   4. Is the following sentence true or false? To decide whether a measurement has

   good precision or poor precision, the measurement must be made more than

   once. ______________________