ONLY FOR MISS HASHMI

Acid-Base Chemistry

Hands-On Labs, Inc.
Version 42-0137-00-02

Lab Report Assistant

This document is not meant to be a substitute for a formal laboratory report. The Lab Report Assistant is simply a summary of the experiment’s questions, diagrams if needed, and data tables that should be addressed in a formal lab report. The intent is to facilitate students’ writing of lab reports by providing this information in an editable file which can be sent to an instructor.

Exercise 1: Using pH Paper and the Indicator Bromothymol Blue (BTB)

Data Table 1. Data Collected from Exercise 1.

ID Number	Chemical Name	Chemical Formula	Hypothesis: Acid or Base	pH	BTB Color	Acid or Base?
11A	Acetic acid	CH3COOH
11B	Hydrogen nitrate	HNO3
11C	Hydrogen sulfate	H2SO4
11D	Phosphoric acid	H3PO4
11E	Sodium acetate	CH3COONa
11F	Sodium bicarbonate	NaHCO3
11G	Sodium dihydrogen phosphate	NaH2PO4
11H	Sodium hydrogen sulfate	NaHSO4
12A	Sodium bisulfite	NaHSO3
12B	Limewater	Ca(OH)2
12C	Trisodium phosphate	Na3PO4
12D	Disodium hydrogen orthophosphate	Na2HPO4
12E	Ammonium hydroxide	NH4OH
12F	Hydrochloric acid	HCl
12G	Sodium carbonate	Na2CO3
12H	Sodium hydroxide	NaOH

Questions

When you created hypotheses to guess whether each chemical was an acid or base, what specifically did you look for in the chemical formulas?
What is the value of using pH paper as an indicator?
What is the value of using BTB as an indicator? When might BTB be a better choice than pH paper?
Write the chemical equation of mixing hydrogen nitrate (HNO3) with water.
Write the chemical equation of mixing ammonium hydroxide (NH4OH) with water.
What are the conjugate acids and conjugate bases of questions D and E?

Exercise 2: Acid-Base Reactions

Data Table 2. Acid-Base Reactions.

A1:

Acetic acid (CH3COOH)

A2:

Hydrogen nitrate (HNO3)

A3:

Hydrogen sulfate (H2SO4)

A4:

Phosphoric acid (H3PO4)

A5:

Sodium dihydrogen phosphate (NaH2PO4)

A6:

Sodium hydrogen sulfate (NaHSO4)

A7:

Sodium bisulfite (NaHSO3)

A8:

Hydrochloric acid (HCl)

BA:

Sodium acetate (CH3COONa)

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Limewater [Ca(OH)2]

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Trisodium phosphate (Na3PO4)

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Disodium hydrogen orthophos-phate (Na2HPO4)

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Ammonium hydroxide (NH4OH)

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Sodium carbonate (Na2CO3)

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Questions

Visually analyze the wells colored with BTB, and remember that acids are organized by columns and bases are organized by rows. What specific acids or bases are weak or strong acids or bases? Explain why.
Why did some of the chemicals neutralize and others did not?
Did any of the mixtures get more acidic than the original acid or less acidic than the original base? Why do you think this happened or did not happen?

Exercise 3: Testing the pH of Household Products

Data Table 3. Household Acids and Bases.

Household substance	Prediction: (Acid, Base, or Neutral)	pH Value	Conclusion: (Acid, Base, or Neutral)

Questions

What properties did you use to determine whether the substances you tested were acid or base?
Did any of your findings surprise you? Why or why not?