Chapter 1 Homework

Chapter 1 Homework
Name
1. a) What kinds of information are needed to formulate a hypothesis
b) Is it possible to disprove a scientific hypothesis
2. Indicate whether each of the following foods are homogeneous or heterogeneous mixtures:
a) solid butter
b) a Snickers bar
c) grape juice
d) an uncooked hamburger
3. Indicate whether each of the following properties is a physical or chemical property of
sodium:
a) Its density is greater than that of kerosene and less than that of water.
b) It has a lower melting point than most metals.
c) It is soft and can easily be cut with a knife.
d) It reacts very vigorously with water, releasing hydrogen gas.

4. How many significant figures are in each of the following measurements
a) 35.0445 g
b) 0.00450 m
c) 0.03050 L
Note:
from this point on, all your answers must have the correct number of significant
figures! Make sure you round off correctly too.
5. Round off the following quantities to the number of significant figures indicated in
parentheses (don’t forget to put the unit of measurement after the number):
a) 7.0001 kg (4)
b) 2.30985 x 10 –4 m (5)
c) 68.507 cm (2)
d) 4.995 x 10 3 mL (3)
6. Do the following calculations and use the correct number of significant figures in your
answer. Assume all numbers are the results of measurements (i.e. none of the numbers
are constants).
a)
( 8.71) 0.0301
0.031
( )
b) ( 2.25!10 –3
)( 8.754 !10 6
)
c) 8.937 !8.930
d) 847.89 !847.73+ 2.5

7. The Eiffel Tower in Paris is 324 m tall, including a 24 m television antenna that was not
there when the tower was built in 1889. What is the overall height of the Eiffel Tower in
kilometers
8. Diamonds are measured in carats, where 1 carat = 0.200 g. The density of diamond is
3.51 g/cm 3 . What is the volume of a 5.0 carat diamond
9. What is the mass of 65.0 mL of ethanol if its density at room temperature is 0.789 g/mL
10. Ethyl chloride acts as a mild topical anesthetic because it chills the skin when sprayed on it.
It dulls the pain of injury and is sometimes used to make removing splinters easier. The
boiling point of ethyl chloride is 12.3°C. What is its boiling point on the Fahrenheit and
Kelvin scales
Bonus.
At what temperature do the Fahrenheit and Celsius scales have the same numerical value
Show your work to receive credit.

11. Three different analytical techniques were used to determine the quantity of sodium in a
Mars Milky Way candy bar. Each technique was used to analyze five portions of the same
candy bar, with the following results (expressed as milligrams of sodium per candy bar):
mg of Na:
Technique 1
mg of Na:
Technique 2
mg of Na:
Technique 3
109 110 114
111 115 115
110 120 116
109 116 115
110 113 115
The actual quantity of sodium in the candy bar was 115 mg.
a) Which of the techniques are precise
b) Which of the techniques are accurate
c) Which of the techniques are both precise and accurate
12. Sodium metal reacts vigorously with water. A piece of sodium weighing 19.70 g was added
to a beaker containing 126.22 g of water. During the reaction, hydrogen gas was produced
and bubbled from the solution. The solution, containing sodium hydroxide, weighed
145.06 g. How many grams of hydrogen gas were produced
13. A gallon of ice cream contains exactly 32 servings, and each serving has 165 Calories, of
which 30.0% are derived from fat. How many Calories derived from fat would you consume
if you ate one-half gallon of ice cream

14. When a teacher gave a “pop quiz,” 18 of the 24 students in the class passed the test. What
percentage of the class did not pass the test
Bonus.
A 33.0 g sample of an unknown liquid at 20.0°C is heated to 122°C. During this heating, the
density of the liquid changes from 0.854 g/mL to 0.797 g/mL. What volume would this
sample occupy at 122°C