Name __________________________________
Density/Lab Practice Quiz 2013
I. Make the following calculations.
1. If a 13.6 gram object takes up a volume of 7.8 ml. What is its density?
2. Aluminum has a density of 2.7 g/ml. What is the mass of a rectangular sample that has dimensions of 1.234
cm, .8762 cm, and 2.345 cm?
3. 21.39 mL of water is placed into a graduated cylinder. A 6.402 gram object is placed into the water and the
water level rises to 25.32 mL. What is the density of the object?
4. How many mL of alcohol would be needed to provide 10.8 g of alcohol if it has a density of .89 g/cm3?
5. If I have a percent error of 4.2% on a calculated value of 2.7 g/mL, what is the actual density?
% error = ( I ( accepted-experimental) I / accepted) x 100
6. If I calculate a density for lead of 9.8 g/mL, and a reference book gives the actual density of lead as 11.1
g/mL, what is my percent error?
II. Use this data table to answer the following Questions.
Mass of cylindrical solid
180.4 g
Height of cylindrical solid
6.4 cm
Diameter of cylindrical solid
3.9 cm
Volume of water
7.2 mL
Volume of water with irregular solid pellets
Mass of empty graduated cylinder
Volume of liquid added to cylinder
Mass of cylinder with liquid
Mass of irregular solid pellets
9.9 mL
7. Fill in the following table
Cylindrical solid
Irregular solid pellets
17.2 g
10.2 mL
25.4 g
7.45 g
Liquid
Mass of
Volume of
Density of
8. Propose a hypothetical identity for each of the three unknown samples based on the following
charts:
Substance
Tin
Zinc
Lead
Magnesium
Aluminum
Iron
Gold
Copper
Density
7.31 g/mL
7.133 g/mL
11.35 g/mL
1.74 g/mL
2.70 g/mL
7.874
19.3 g/mL
8.96 g/mL
Substance Density
Nickel
8.91 g/mL
Mercury
13.55 g/mL
Water
1.0 g/mL
Cyclohexane .32 g/ml
Acetone
.45 g/mL
N-propanol .786 g/ml
Gasoline
.67 g/m
9. Would the number of metal pellets, or the amount of liquid used change your density calculations?
Why or why not?
III. Use this data table to answer the questions that follow
% sugar
0
5
10
15
20
?????
Density
1.00 g/mL
1.08 g/mL
1.13 g/mL
1.22 g/mL
1.30 g/mL
1.17 g/mL
10. Plot density versus concentration for the five reference solutions on a graph. The concentration is
the independent variable (x-axis) and the density is the dependent variable (y-axis). Use a ruler to
draw a “best fit” straight line through the data points.
11. Use the graph to estimate the unknown sugar concentration in the unknown beverage.
12. If the accepted value of sugar in the beverage is 11%, what is your percent error?
IV. Use this data table to answer the following questions.
Volume of 50 drops of oil
Diameter of major axis
1.7 mL
26.3 cm
Volume of 100 drops of oil
Diameter of minor axis
3.3 mL
19.9 cm.
13. Using the values from your data table, calculate the average volume of a single oil drop in mL.
14. Assume that the oil drop formed a cylindrical ellipse. (The equation for the volume of a cylindrical
ellipse is v =πabt where a is the minor radius, b is the major radius, and t is the thickness of the oil
film.) Calculate the thickness of the oil film.
15. The thickness of that oil film is the length of a molecule which contains 19 carbon atoms.
Calculate the diameter of 1 of these carbon atoms.
16.. For each of the following possible errors, discuss what effect it would have had on your
calculated diameter and explain why.
a. If the oil was unable to spread out completely because it hit the sides of the tray.
b. If you placed too much lycopodium powder on the surface of the water and the resistance
of the powder didn't let the oil film spread out as much as it could have.
V. Use this data table to answer the questions that follow.
Mass of galvanized iron 17.8 g
Width of iron piece 4.3 cm
Mass of ungalvanized iron 17.3 g
length of iron piece 5.2 cm
17. Find the difference in the mass of the galvanized iron square before and after being soaked in
acid.
18. If the accepted density of zinc is 7.14 g / ml, use the difference in mass to calculate the volume of
zinc removed from the square.
19. If all of the volume of zinc removed is assumed to be made of zinc atoms (no empty space), and
the volume of a zinc atom is 1 x 10-23 cm3 , how many zinc atoms were removed from the piece of
metal?
20. That zinc removed was from both sides of the metal square. How much volume of zinc was
removed from just one side?
10. That volume of zinc is equal to the width of the zinc removed times the length of the zinc
removed time the thickness of the zinc removed. Using the values from your data table, calculate the
thickness of zinc removed.
11. How many layers of zinc atoms were removed from one side of the galvanized metal square if
zinc atoms have a diameter of 2.68 x 10-8 cm?