1.H2O
2. H2SO4
3.NaCl
4.NaOH
5.HCl
6.NaHCO3
Our Samples:7.NaClO
8.NH3
9.CH3COOH
10. CH3CHOHCH3
11. C12H22O11
12. CuSO4
This is a drop plate. It has twelve wells in it.
well well well well
well well well well
well well well well
pH paper bluelitmuspaper
redlitmuspaper
The color code chart in the pH paper container applies only to the pH paper. It does NOT apply to the litmus paper.
pH paperColor codechart
“STRONG” dissociation
2. H2SO4 sulfuric acid
“weak” dissociation
H2SO4 + H2O H3O+ + HSO4-
HSO4- + H2O H3O+ + SO4
2-
strong acid
weak acid
6. NaHCO3
sodium hydrogen carbonate
sodium bicarbonate
baking soda
NaHCO3(cr) Na+(aq) + HCO3-(aq)
HCO3-(aq) + H3O+(aq) H2CO3(aq) + H2O(l)
base
7. NaClO
sodium hypochlorite
bleach
http://www.bioworldusa.com/household/ph-scale-comparisonssays the pH of bleach is 12.6
NaClO(cr) Na+(aq) + ClO-(aq)
ClO-(aq) + H3O+(aq) HClO(aq) + H2O(l)base
H2O
Cl2 =
Cl- =
ClO- =
ClO2- =
ClO3- =
ClO4- =
“chlorine”
“chloride”
“chlorate”
“chlorite”
“hypochlorite”
“perchlorate”
The hypochlorite ion found in liquid chlorine bleach is just one of a series of chlorine-containing species.
10. CH3CHOHCH3
isopropanol
isopropyl alcohol
rubbing alcohol
CC C
H
HH
H
HH
H
The OH in an alcohol molecule doesn’t come off in water.
base ?
12. CuSO4
copper sulfate
CuSO4 Cu2+(aq) + SO42-(aq)
Cu2+(aq) + 2OH-(aq) Cu(OH)2(cr)acid
SO42-(aq) + H3O+(aq) HSO4
-(aq) + H2O(l)base
A 0.2M solution is said to have a pH of 4.
1. What is the relationship between the pH of a sample and its effect upon the two colors of litmus paper?
CONCLUSIONS:
“Blue litmus paper turns red under acidic conditions and red litmus paper turns blue under basic (i.e. alkaline) conditions, with the color change occurring over the pH range 4.5-8.3 at 25 °C. Neutral litmus paper is purple.”
Your results may not be exactly the same as everyone else’s, so you have to answer the question based on your data. However, here’s what wikipedia says:
That’s not quite as simple as what I was brought up to believe, but what we are taught in school is often an over-simplification of reality.
Blue (top) and red (bottom) litmus paper. When litmus paper is placed in acid, the red stays red (bottom right) and the blue turns red (top right). When litmus paper is placed in base, the blue stays blue (top left) and the red turns blue (bottom left).
CONCLUSIONS:2. What liquid indicator did you use? What is the relationship between the pH of a sample and the color it turned when the liquid indicator was mixed with it?
If the pH was less than or equal to 7, the phenolphthalein remained clear.
If the pH was greater than 7, the phenolphthalein turned hot pink (fuchsia/magenta).
We used phenolphthalein as our liquid indicator in this lab.Click me to remove me
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