Homework due March 23, 2017 Classifying Matter Worksheet
Classify each of the following substances as an element, a compound, a
solution (homogenous mixture, or a heterogeneous mixture.
1. Sand 2. Salt 3. Pure Water
4. Soil 5. Soda just opened 6. Pure air
7. Carbon Dioxide 8. Gold 9. Brass
10. Oxygen 11. Italian Salad Dressing 12. Salt Water
13. Raisin Bran 14. Silver 15. Lithium Iodide
16.
Apple Pie 17.
Kool Aid 18.
Sugar Water
19.
Chocolatechip Cookie 20.
Gatorade 21.
Gold
22. tacos 23.Lead 24. Ceasar Salad
25. Calcium 26.
Whole Milk 27. Skim
Milk
28. hydrogen peroxide 29.
Potassium 30. Sugar
31. Raisin Bran Cereal with Milk 32. Raisin Bran Cereal without Milk
Vocabulary Cards
Use the example below, make vocabulary cards for the
following words on the template. You will include: the word it self, the definition of the word, a sentence using the word and an illustration (picture) of the word
Homework Due March 15, 2017 (This homework is only for First and Third Period Class. The one for Fourth Period is posted on Edmodo.)
We saw in class how to count significant figures. Here I will explain how to use the significant figures in Multiplication, Division, Adition and Substraction. Then you must go on Edmodo.com and solve the problems posted there.
Remember that there are three rules on determining how many significant figures are in a number:
Non-zero digits are always significant.
Any zeros between two significant digits are significant.
A final zero or trailing zeros in the decimal portion ONLY are significant.
The following rule applies for multiplication and division:
The LEAST number of significant figures in any number of the problem determines the number of significant figures in the answer.
This means you MUST know how to recognize significant figures in order to use this rule.
Example #1: 2.5 x 3.42.
The answer to this problem would be 8.6 (which was rounded from the calculator reading of 8.55). Why?
2.5 has two significant figures while 3.42 has three. Two significant figures is less precise than three, so the answer has two significant figures.
Example #2: How many significant figures will the answer to 3.10 x 4.520 have?
You may have said two. This is too few. A common error is for the student to look at a number like 3.10 and think it has two significant figures. The zero in the hundedth's place is not recognized as significant when, in fact, it is. 3.10 has three significant figures.
Three is the correct answer. 14.0 has three significant figures. Note that the zero in the tenth's place is considered significant. All trailing zeros in the decimal portion are considered significant.
Another common error is for the student to think that 14 and 14.0 are the same thing. THEY ARE NOT. 14.0 is ten times more precise than 14. The two numbers have the same value, but they convey different meanings about how trustworthy they are.
Four is also an incorrect answer given by some ChemTeam students. It is too many significant figures. One possible reason for this answer lies in the number 4.520. This number has four significant figures while 3.10 has three. Somehow, the student (YOU!) maybe got the idea that it is the GREATEST number of significant figures in the problem that dictates the answer. It is the LEAST.
Sometimes student will answer this with five. Most likely you responded with this answer because it says 14.012 on your calculator. This answer would have been correct in your math class because mathematics does not have the significant figure concept.
For addition and subtraction, look at the decimal portion (i.e., to the right of the decimal point) of the numbers ONLY. Here is what to do:
1) Count the number of significant figures in the decimal portion of each number in the problem. (The digits to the left of the decimal place are not used to determine the number of decimal places in the final answer.)
2) Add or subtract in the normal fashion.
3) Round the answer to the LEAST number of places in the decimal portion of any number in the problem.
WARNING: the rules for add/subtract are different from multiply/divide. A very common student error is to swap the two sets of rules. Another common error is to use just one rule for both types of operations.
Example 1:
98.123 + 6.6 = 104.723 but in order to follow the rule we have to round it up to 104.7 because 6.6 has only one decimal place
Example 2:
54.732 + 87.4321 + 9.3421 = 151.5062 but we have to round it to 151.506 because the number with the least decimal places has only 3 decimal numbers which is 54.732
Aluminum metal melts at 660.37 °C. What is the temperature in Kelvin?
Question 2
Gallium is a metal that can melt in your hand at 302.93 K. What is the
temperature in °C?
Question 3
Body temperature is 98.6 °F. What is the
temperature in °C?
Question
4
The title of the book "Fahrenheit 451"
refers to the temperature book paper burns, or 451 °F. What is the temperature
in °C?
Question
5
Room temperature is often used in calculations
as 300 K. What is the temperature in Fahrenheit?
Question 6
The average surface temperature on Mars is -63
°C. What is the temperature in °F?
Question
7
Oxygen has a boiling point of 90.19 K. What is
the temperature in °F?
Question
8
Pure iron melts at 1535 °C. What is the
temperature in °F?
Question
9
Which temperature is hotter: 17 °C or 58 °F?
Question
10
A general rule of thumb used by pilots is for
every 1000 feet of altitude, the temperature falls 3.5 °F. If the temperature
at sea level is 78°F, what would you expect the temperature to be at 10,000
feet in °C?
Watch the following video to remember how to multiply and divide numbers written in Scientific Notation and then go on Edmodo and Do the 12 exercises due tomorrow.
13.The builder measures the perimeter of
the foundation to be 425 ft. He must order steel beams to install around the
perimeter of the foundation. Steel must be ordered in meters. How many meters
of steel should the builder order?
14.Mrs. Jacobsen purchased a 5-pound
package of ground beef for $12.40. She decided to use 8 ounces each day for
dinner recipes. What was the cost of ground beef per meal?
15.Car 1 drove 408 miles in 6 hours and Car
2 drove 365 miles in 5 hours during the cross-country road race. Who had the
fastest average speed?
