Measuring Mass and Volume-Chemistry

1. MASS
Prepared by: Ms. Diana Rose D. Dimapasoc

2. MASS
• Is the amount of matter in an
object
•Basic unit: Kilogram (kg)

3. Examples

4. Measuring Mass
A. Balance Rules
1. Always check the balance is level before using it.
2. Never weigh directly on the balance pan. Always use a
piece of weighing paper to protect it.
3. Never add chemicals to a container or piece of weighing
paper while it is on the balance.
4. Do not weigh hot or cold objects.
5. Clean up any spills around the balance immediately.

5. Measuring Mass
Triple Beam Balance
1. Place the object to be measured on the pan at the left
side of the balance.
2. Slide the movable masses to the right until the right end
of the arm is level with the balance mark. Start by moving
the larger masses and then fine tune the measurement by
moving the smaller masses as needed.

6. Measuring Mass
Triple Beam Balance
3. Read the three
scales to determine
the values of the
masses that were
moved to the right.
Their combined mass
is equal to the mass
of the object.

7. Measuring Mass
B. Direct Weighing
Direct weighing means that an object is placed
directly on a balance and the mass read.
Weighing directly requires that the balance be
carefully zeroed (reads zero with nothing on
the balance pan) in order to obtain accurate
results.

8. Measuring Mass
C. Weighing by Difference
1. (mass of paper + substance) – (mass of paper)
= mass of substance
2. (mass of container + substance) - (mass of
container + substance after removal) =
mass of substance removed

9. Measuring Mass
D. Taring
By taring a balance the process of weighing by
difference is done automatically. When a
balance is tared with an object on the balance
pan, the weight of the object will be
automatically subtracted from every reading
until the balance is re-tared or zeroed.

10. Measuring Mass
D. Taring (Example)
A beaker is placed on the balance pan and the
tare button pushed. Zeroes should appear on
the display (the mass of the beaker minus the
mass of the same beaker should equal zero). If
a substance is now added to the beaker, just
the mass of the substance is displayed.

11. VOLUME

12. VOLUME
•the space occupied by an object
• Basic unit: Liter (L)

13. Measuring Volume
A. Regular Geometric Shapes
rectangular box

14. Measuring Volume
A. Regular Geometric Shapes (Example)
A rectangular box is 20 cm long, 30 cm
wide, and 15 cm high. What is the
object’s volume?

15. Measuring Volume
B. Irregularly Shaped Solids
A volume of water sufficient to cover the object
is placed in a graduated cylinder and the
volume is read. The object is added to the
cylinder and the volume is read again. The
difference between the two volumes is the
volume of the object.

16. Measuring Volume
B. Irregularly Shaped
Solids (Example)
The first volume reading (on
the left) is 12.4 ml. After the
battery has been added, the
second volume reading (on
the right) is 20.2 ml. The
volume of the battery is 20.2
- 12.4 or 7.8 ml.

17. Measuring Volume
C. Measuring the Volume of Liquids
Volumetric glass wares such as beaker,
Erlenmeyer flask, graduated cylinder,
pipets, and the likes are used to make
measuring easier.

18. Measuring Volume
C.1. Volumetric Glass Wares Classifications:
a. Those designed to CONTAIN SPECIFIED
amount of liquid (e.g. volumetric flasks,
graduated cylinder)
b. Those designed to DELIVER a SPECIFIED
amount of liquid (e.g. pipets and burets)

19. Measuring Volume

20. Measuring Volume

21. Measuring Volume
Graduated Cylinders
The glass cylinder has
etched marks to indicate
volumes, a pouring lip
and quite often, a plastic
bumper to prevent
breakage.

22. Measuring Volume

23. Measuring Volume

24. Measuring Volume

25. Measuring Volume

26. Measuring Volume

27. Measuring Volume
D. Measuring the Volume of Gases
• Displace fluid - The volume of fluid displaced would
equal the volume of the gas.
• Use a gas syringe - This is a laboratory instrument
that can be used to withdraw a certain volume of
gas from a closed system or to measure the
volume of gas from a chemical reaction.

28. Measuring Volume
D. Measuring the Volume of Gases
• Use a spirometer - It measures the volume of
air coming into and being expelled out of your
lungs, called tidal volume.
• Trap the gas - Use a balloon to trap the gas
coming from a reaction. Then calculate the
volume of the sphere.

29. Measuring Volume
D. Measuring the Volume of Gases
• For the volume of compressed gas in a cylinder, apply
this equation:
Ideal Gas Law: PV = nRT, where,
P = pressure,
V = volume,
n = the number of moles,
R = the gas constant and
T = the absolute temperature

30. SOURCES
• http://www.harpercollege.edu/tm-
ps/chm/100/dgodambe/thedisk/labtech/mass.htm
• https://en.wikipedia.org/wiki/Mass
• https://www.ck12.org/chemistry/scientific-measuring-
devices/lesson/Scientific-Measuring-Devices-MS-PS/
• https://en.wikipedia.org/wiki/Volume
• http://www.harpercollege.edu/tm-
ps/chm/100/dgodambe/thedisk/labtech/volume.htm
• http://www.harpercollege.edu/tm-
ps/chm/100/dgodambe/thedisk/labtech/solvol.htm
• http://examples.yourdictionary.com/examples-of-ways-to-measure-
volume.html
• www.sciencegeek.net