DENSITY AND EXAM
REVIEW DAY
DO NOW (CATALYST) (10 MIN)
1. What is the density of 48 g of a metal if the
metal raises the level of water in a
graduated cylinder from 25 mL to 33 mL?
2. What is the density of a liquid if it weighs
10g and occupies a volume of 5 mL?
3. What is the difference between a constant
and a control?
4. What is the difference between the
independent and dependent variables?
HOMEWORK 2 REVIEW
1. What is the density of 10 g of a metal if the metal
raises the level of water in a graduated cylinder
from 25 mL to 45 mL?
2. What is the density if 50 g of a metal occupies a
volume of 5 cm3?
3. If you were trying to test whether Advil or Tylenol
reduced fevers more, write a problem statement,
hypothesis and variables for an experiment you
could perform.
HOMEWORK 2 REVIEW
3. If you were trying to test whether Advil or Tylenol reduced fevers more,
write a problem statement, hypothesis and variables for an experiment
you could perform.
Problem Statement: Is advil or tylenol more effective in
reducing fevers
Hypothesis: If I take advil and tylenol, then advil will
reduce my fever more because it is faster acting
Independent: Advil and Tylenol
Dependent: fever temperature
Control: fever temperature without taking
Advil/Tylenol
Constants: amount of medicine, frequency of
medication, etc
ANNOUNCEMENTS
• First exam next class
• Covers unit conversion, scientific method,
precision/accuracy, density and lab safety
• Download ‘Exam Review Notes’ from the
‘Student Notes’ section of the class website
• If you have any questions stay after school
or email khagan@dadeschools.net
AGENDA / OBJECTIVES
• Finish Density Lab Activity (10 min)
• Precision/accuracy mini lesson (10
min)
• Exam Review Stations (60 min)
• Final Questions (10 min)
DENSITY OF WATER CALCULATIONS
• Obtain your density lab calculations from last class.
Calculate the density of the water. (4 min)
• Mass of water (g)
=(mass of graduated cylinder + water) – (mass of empty
graduated cylinder)
=(final mass of g.c.) – (initial mass of g.c.)
• Volume of water (mL) – level of water shown on graduated
cylinder
• Density (g/mL) = mass/volume
• Once you are finished, complete the rest of your
density calculations in the tables
WERE OUR MEASUREMENTS
ACCURATE OR PRECISE?
Precision = how
close
measurements are
to each other
Accuracy =how
close the
measurements are
to the “true” value
DENSITY LAB OBSERVATION
QUESTIONS (10 MIN)
Answer the following questions in your lab notebook:
1. What could you do to improve the accuracy of your
measurements?
2. How does the density of the weight compare to the density
of water? Which is denser?
3. Nickel (metal) has a density of 8.91 g/mL. Compare this to
the density of the nickel coin you calculated. Is the nickel
coin made of pure nickel (metal)?
4. When you use the terms heavier or lighter to compare
different objects with the same volume, what property of the
objects are you actually comparing?
5. The density of aluminum is 2.70 g/cm3. What volume will 13.5
grams of aluminum occupy? HINT, use unit conversion!
EXAM REVIEW STATIONS (60 MIN)
• There are 4 stations at the lab benches, you
will have 15 min at each station.
• If you have questions, first look at notes, then
ask group member, finally ask teacher
• This is your LAST CHANCE to practice before
the exam, USE YOUR TIME WISELY!
• Review problems are similar to exam problems
• All answers are posted online
ANY FINAL QUESTIONS?
PROBLEM
What is the density of 35 g of a metal if the
metal raises the level of water in a
graduated cylinder from 25 mL to 30 mL?
30 mL
25 mL
PROBLEM
A mystery liquid has a density of 10 g/mL.
What is the mass of 5 mL of mystery
liquid?
PROBLEM
•
Silver has a density of 10.5 g/cm3.
What is the volume of a 5.25g silver coin
in cubic centimeters?
PROBLEM
If you wanted to see which makes you
gain more weight, eating hot cheetos for
lunch or eating snickers for lunch. Your
experiment would have:
• Independent Variable:
__________________________________
• Dependent Variable:
____________________________________
PROBLEM
•
If you wanted to see which makes you
gain more weight, eating hot cheetos for
lunch or eating snickers for lunch. Your
experiment would have:
• Independent Variable:
__________________________________
• Dependent Variable:
____________________________________
PROBLEM
•
If you wanted to test if drinking milk
helps you jump higher, your experiment
would have:
• Independent Variable:
__________________________________
• Dependent Variable:
_________________________________
PROBLEM
•
Ms. Van Duyn decides to do a little
experiment on her students. She tells one
group of students not to study for the test.
She then has another group stay after
school to study for one hour. She has a third
group stay after school and study for two
hours. When the students take the test, she
compares the grades the different groups
got.
PROBLEM
A baker decides to do a chemistry
experiment. He makes four different cakes.
He adds no flour to the first cake. He adds
two cups to the second cake, three cups to
the third cake, and four coups to the fourth
cake. He then checks how high the cakes
rise
PROBLEM
A student wants to find out if diet coke
helps her stay up late. She doesn’t drink
diet coke one night. The next night she
drinks one diet coke. The next night she
drinks two diet cokes. She notes the time
she starts to feel sleepy each night.
PROBLEM
In the North, the government puts salt on
the roads during the winter to melt the ice.
Some environmentalists are worried that this
is harmful to plants near the roads. To test
this theory they perform an experiment.
They have a control group of plants and an
experimental group. No salt is given to the
control group of plants for two weeks. Salt is
put in the soil of the experimental group for
two weeks. At the end of the two weeks the
growth of the two groups is measured.