Transcript Activity 50 Title: The Chemistry of Acids and Bases Read pg. C-98 Problem: What chemical reaction takes place when you neutralize an acid or base? Hypothesis/Initial Thoughts:

Activity 50
Title:
The Chemistry of Acids
and Bases
Read pg. C-98
Problem: What chemical reaction takes
place when you neutralize an acid or base?
Hypothesis/Initial Thoughts:
Do you think that the ability of an
acid and a base to neutralize each
other is a chemical or a physical
property?
• A chemical property requires interaction
of chemicals which produces new
substances with different properties
• There is pH change
• You may infer this provides evidence
that a new substance is produced
Electrical Conductivity Demo
• Electrical conductivity is the ability of a
solution to conduct electrical current
• In a solution, the concentration of free
ions determines how well the liquid
conducts electricity
• Create a table and record the results of
the conductivity of 7 different solutions
• Make a prediction before the demo
begins
Data/Observation:
Table 1: Testing Electrical Conductivity of Solutions
Solution
pH
Prediction
Conductive?
1. Distilled Water
7
No
Around 7
Yes
7
No
7
Yes
2
Yes
10-11
Yes
7
Yes
2. Tap Water
3. Distilled water +
sugar
4. Distilled water +
table salt (NaCl)
5. Acid (HCl)
6. Base (KOH)
7. Neutralization
acid-base
Results
• Table salt, sodium chloride (NaCl)
conducts electricity when dissolved, but
has a balanced, neutral pH
• This is the same for the neutralized acidand-base solution
• Using pH and conductivity, you cannot
distinguish the difference between
neutralized solutions and saltwater
Do you have any ideas about why the
HCl plus KOH still conduct electricity,
even though it is neutral?
• The product of neutralization is salt
• HCl provides chloride ions and KOH
provides potassium ions
• K (potassium) is in the same family as
Na (sodium)
How could we test the idea that there
is salt in the mixture of HCl and KOH?
• Evaporate the water out of the mixture
to see if a solid resembling salt remains
• We will do this and look at it next class
period
Before you begin reading:
• A three-level reading guide will be the
second part of your data/observation for
this activity
• Review the statements in the reading
guide before you begin
• As you finish each section or after you
finish reading, check off the statements
you agree with