Init: 5/25/2011 by Daniel R. Barnes

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

Your liquid indicator in this lab is . . .

phenolphthalein

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

Please do the lab before

proceeding any further.

Thank you.

1. H2O

acidbase

water

Hydrogen hydroxide

Hydronium hydroxide

“STRONG” dissociation

2. H2SO4 sulfuric acid

“weak” dissociation

H2SO4 + H2O H3O+ + HSO4-

HSO4- + H2O H3O+ + SO4

2-

strong acid

weak acid

3. NaCl sodium chloride

NaCl(cr) Na+(aq) + Cl-(aq)

“table salt”

4. NaOH sodium hydroxide

NaOH(cr) Na+(aq) + OH-(aq)

“lye”

base

5. HCl hydrogen chloride

HCl(g) + H2O(l) H3O+(aq) + Cl-(aq)

hydrochloric acidacid

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.

8. NH3

ammonia

ammonium hydroxide

NH3(g) + H2O(l) NH4+(aq) + OH-(aq)

base

9. CH3COOH

acetic acid

ethanoic acid

vinegar

CH3COOH(aq) + H2O(l) H3O+(aq) + CH3COO-(aq)acid

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 ?

11. C12H22O11

sucrose

table sugar

The OH in a sugar 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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