Transcript Gas

The three common states of matter are:
Definite volume
Definite shape
Definite volume
Indefinite shape
Indefinite volume
Indefinite shape
Element, compound, solution or heterogeneous mixture??
1. One type of atom.
Element
2. Sugar dissolved in water.
Solution
3. Dirt.
Heterogeneous mixture
4. Air.
Solution
5. A 24 caret gold ring.
Element
Element, compound, solution or heterogeneous mixture??
6. Water.
Compound
7. Carbon dioxide gas.
8. An 8 caret gold ring.
Compound
Solution
9. The contents of your junk drawer.
Heterogeneous mixture
10. Ice.
Compound
Math with Significance
1) 1.0 (1.00+1.000) = 1.0 (2.00) = 2.0
2) (1.000 +1.000)/(0.09 + 0.01) = 2.000/0.10 = 20.
3) 0.50 (2 + 2.0) = 0.50 (4) = 2
4) A rock weighing 7.05 g is dropped into a
graduated cylinder containing 5.1 mL of water.
What is the density of the rock if the final
volume of water is 10.5 mL?
D = m/V = 7.05 g/(10.5 mL -5.1 mL) = 7.05 g/5.4 mL
D = (1.3055556 g/mL) = 1.3 g/mL
1) For an experiment in which you are determining the freezing
point of an unknown chemical, you record the temperature
every minute for 20 minutes. In this example, time is the —
A. control
B. dependent variable
C. independent variable
D. hypothesis
2) In the chemistry lab, chemicals that you are finished working
with should be —
A.
B.
C.
D.
poured into the sink
returned to their original containers
mixed together and dumped in a designated container
disposed of as directed by your teacher
3) In chemistry lab, a student was instructed to find the density of
a rectangular piece of aluminum. After careful measurement, he
recorded a mass of 31.44 g and a volume of 11.7 cm3. Using
the formula density = mass/volume and a calculator, his answer
was 2.6871794 g/cm3. Which of these is the correct answer to
report for the density of the aluminum?
A. 2.7 g/cm3
B. 2.69 g/cm3
C. 2.687 g/cm3
D. 2.68 g/cm3
4) A student told the class that she takes 500 mg of vitamin C
every day. What is this mass expressed in grams?
A. 0.05 g
B. 0.5 g
C. 5.0 g
D. 500,000 g
5) The table shows the data obtained by four groups of students
during a lab investigation designed to determine the boiling
point of methanol. The accepted value for the boiling point of
methanol is 78.5C. Whose data was the most precise?
A. Group AB. Group B
C. Group C D. Group D
Temperature (°C) Time (minutes)
10
33
20
16
30
8
40
4
50
2
A group of students investigated how temperature affects the rate
of chemical reactions. They used hydrogen peroxide, which
breaks down into oxygen and water, for their experiment. The
students measured how long it took to obtain 50 mL of oxygen gas
from a given volume of hydrogen peroxide heated to different
temperatures. Their data is shown in the table above.
6) Select the best way for the students to reduce the experimental
error in their investigation.
A. Test more than one variable at a time.
B. Perform repeated trials.
C. Change their answers if they do not match their hypothesis.
D. Perform the experiment only one time.
7) Characteristics of a substance can be classified as physical
properties or chemical properties. Which of the following is a
chemical property?
A. Boils at 56°C
B. Tastes sour
C. Has a density of 2.9 g/cm3
D. Reacts with acid to produce hydrogen gas
8) Select the observation that does NOT support the conclusion
that a chemical reaction took place.
A. Liquid water changed to water vapor.
B. A precipitate was formed.
C. An odor developed.
D. Temperature rose.
9) Reese’s teacher gave her three test tubes, each containing a
different unknown liquid sample of a given density. Reese
added orange food coloring to each test tube and then
calculated the density of the sample. She place the data she
collected in the data table. She concluded that the added food
color increased the density of the sample. What is another
reasonable interpretation of the data?
Initial Food Color
Final
Density
Added
Density
(grams/cm3) (mL) (grams/cm3) Final Color
Sample A
0.91
1
1.1
light orange
Sample B
0.94
5
1.2
orange
Sample C
0.92
7
1.2
blue
A. Sample A is a different substance than Sample B.
B. Sample C is a different substance than Samples A or B.
C. All three samples contain water.
D. None of the samples contain water.
10) Which of these is NOT evidence of a chemical reaction?
A. An iron nail changes to a brownish-orange color.
B. An ice cube melts into liquid water.
C. An antacid tablet produces bubbles of gas when placed in
water.
D. A piece of zinc raises the temperature of an acid as it
reacts with it
11) Distillation is a separation technique that involves
A. using a porous barrier to separate a solid from a liquid
B. separating dissolved substances based on their tendency
to be drawn across a surface
C. the formation of pure, solid particles of a substance from a
solution containing the dissolved substance
D. separating two or more liquids based on differences in their
boiling points
Figure 1 shows a graduated cylinder that contained 25 mL of
water. The mass of the cylinder and water was 68.0 g. Fig. 2
shows the same cylinder after a metal sample was lowered into
the cylinder. The water level rose to the 30.0 mL mark; the mass
of the cylinder, water and sample increased to 77.0 g.
12) What is the identity of the
substance?
A. iron
B. nickel
C. titanium
D. magnesium
13) There is some error associated with the density calculation of
the metal in the cylinder. What is its MOST likely source?
A. improperly reading the volume of the sample
B. selecting an irregularly shaped metal sample
C. selecting the wrong glassware for this measurement
D. use of the wrong liquid medium
14) Professor Bothwell determined from the wrapper the number
of calories in a candy bar. He then burned the entire candy bar
and measured the amount of heat released. His experiment
was most likely designed to demonstrate the —
A. law of conservation of matter B. law of disorder
C. law of conservation of energy D. law of constant composition