1. Gas Mass & Conservation of Mass
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2. Gas Mass & Conservation of Mass
Solid
Atomic view
Fixed shape
Fixed volume
No volume change under pressure
Particles fixed in place
in regular array

3. Gas Mass & Conservation of Mass
Liquid
Atomic view
Particles arranged randomly
Free to move while maintaining contact with neighbors
Takes shape of container
(not necessarily filled)
Defined volume
Slight volume change under pressure

4. Gas Mass & Conservation of Mass
Takes shape and volume of its container
Large volume changes with pressure
Atomic view
Particles widely separated
Moving fast and independently

5. Mass is the quantity of matter in an object (traditional)
Mass Measurement
Mass is the quantity of matter in an object (traditional)
Balances
Independent of location
Standard Kilogram

6. Weight
F = ma
W = mg
Weight = m x g where g is the gravitational acceleration
Spring Balance
Depends on location
as g varies
from place to place

7. Gas Mass & Conservation of Mass
Does a gas have mass??

8. Gas Mass & Conservation of Mass
Item
Measured
Mass
Difference
Identity A
Bag Clip B
Balloon C
Baking Soda + container D
Balloon containing Baking Soda
D-B =
Mass of baking soda E
Bottle + Vinegar F
Bottle + Vinegar + Balloon + Baking Soda
(before addition)
D+E = G
(after addition)
Is there a difference between F and G? H
Balloon + Clip
H-B-A =
Mass of gas! I
Bottle + Vinegar + Baking Soda
E+(D-B)=
Mass conserved? J
Bottle + Lime + water K
Balloon + Bottle + Lime + clip
H+J= L
Balloon + Bottle + Lime + clip
(after reaction)
Was mass conserved??
VOLUMES
Volume(mL) M
Vinegar used N
Vinegar + baking soda
N-M = O
Vinegar + baking soda + sand
O-N =

9. Gas Mass & Conservation of Mass
When 1 ton of Indiana coal (Carbon) is burned to generate electricity, the amount of carbon dioxide formed is
Less than 1 ton
Equal to 1 ton
More than 1 ton
Can’t tell without more information

10. Gas Mass & Conservation of Mass
When 1 ton of Indiana coal (Carbon) is burned to generate electricity, the amount of carbon dioxide formed is
Less than 1 ton
Equal to 1 ton
More than 1 ton
Can’t tell without more information
C + O2 → CO2

11. Gas Mass & Conservation of Mass
Reactions
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12. Gas Mass & Conservation of Mass
Combustion
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13. Gas Mass & Conservation of Mass

14. Gas Mass & Conservation of Mass
Buoyancy correction
In the experiment we expected that the mass would not change as reaction took place according to the principle of conservation of mass.
However we observed that the mass of the balloon, bottle, vinegar and baking soda combination decreased as the carbon dioxide was formed and blew up the balloon. The apparent loss of mass was because we did not employ a buoyancy correction.
The expanding balloon displaced an equal volume of air

15. Gas Mass & Conservation of Mass
Volume of balloon = volume of air displaced
Mass of air displaced = Volume of balloon x density of air
Apparent mass loss = Mass of air displaced
Mass lost = 4/3 ∏𝒓𝟑∗𝟎.𝟎𝟎𝟏𝟐𝟕 𝒈/𝒄𝒎𝟑. = 3.8 g
for r = 3.5” = 8.89 cm