Lab: Conservation of Mass
Part A: Mass of Dissolved Salt
• Mass everything before
Part A: Mass of Dissolved Salt
• Pour salt into water.
• Solid to liquid
• Mass everything after
Number of Lab Groups (#)
Part A
10
9
8
7
6
5
4
3
2
1
0
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
Mass Lost or Gained (g)
0.2
0.3
0.4
0.5
Dissolving salt into water
is a Physical Change
Part B: Mass of Ice and Water
• Mass everything before
Melting ice is a Physical Change
Part B: Mass of Ice and Water
• Mass everything after.
• Solid to liquid
• What do you need to do
with the condensation on
the bottle?
Part B
Class discussion on
Poor Procedure
4.5
Numper of Lab Groups (#)
4
3.5
3
2.5
2
1.5
1
0.5
0
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
Mass Lost or Gained (g)
0.3
0.4
0.5
Increase caused by CONDENSATION left
on the outside of the bottle
MASS WAS CONSERVED !
Part C: Mass of Mixed Solutions
• Mass everything before
• Solution A + B
• Solution A + C
Part C: Mass of Mixed Solutions
• Mass everything before
• Solution A + B
• Solution A + C
• Liquid + Liquid
turned to solid
(precipitate)
• Signs of
Chemical Change
- precipitate
- color change
Part C: Mass of Mixed Solutions
Part C
8
Number of Lab Groups (#)
7
6
5
4
3
2
1
0
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
Mass Lost or Gained (g)
0.2
0.3
0.4
0.5
Part D: Mass of Copper and Sulfur
• Mass everything before
• Heat over Bunsen burner
• Gas produced and kept
within the closed system by
the balloon
•Sublimation
(physical change)
(Sulfur going from a
solid to a gas)
•Sulfur reacting with
copper is a chemical
change – color
change gas
produced
Part D: Mass of Copper and Sulfur
• Mass everything after
Part D
10
Lnumber of Lab Groups (#)
9
8
7
6
5
4
3
2
1
0
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
Mass Lost or Gained (g)
0.3
0.4
0.5
Part E: Mass of Gas
• Mass everything before
Part E: Mass of Gas
• Mass everything after
Loosen the lid – listen
for gas escaping.
Recap and Re-measure.
Chemical
Change
-Fizzing, gas
produced
Lower mass because
GAS escaped
Part E: Mass of Gas
Part E
6
Number of Lab Groups (#)
5
4
3
2
1
0
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
Mass Lost or Gained (g)
0.2
0.3
0.4
0.5
• Poor Data –
My guess people
recorded the
mass after letting
gas escape!
• Mass should
have been
CONSERVED