Transcript Acids, Bases, & ph LaB

Acids, Bases, & ph Lab
Page 101
Red cabbage water is an indicator of pH. Although it can't be
used to determine exact pH, it can distinguish between acid (pH
of 0 to 6), neutral (pH near 7), and base (pH of 8 to 14).

acid
0
1
neutral
2
3
4
5
6
7
base
8
9
10 11 12 13 14
2. In this activity:
 If the indicator turns the solution red or
pink, the solution is an acid.
 A purple solution indicates that it is
neutral, neither an acid nor a base.
 If the indicator turns the solution blue or
green, the solution is a base.


1. What is the role of a pH indicator?
 The
measurement of how much acid
or base is in a solution.
 2a.The
 red
range of pH:
(cabbage juice)
or pink = an acid.
 purple = neutral
 blue or green=base.
 2b.
Red Litmus Paper
 2c.
Blue Litmus Paper
 If
the red litmus paper turns red, then
its neutral or an acid.
 If
the blue litmus paper turns blue,
then it’s neutral or a base.
Acids & Bases
 1.
Which of your solutions has the
highest concentration of H+ ions?
 Lemon,
vinegar, apple juice, and
mystery solution A (hydrogen peroxide)
 Lemon is the highest!!
 2.
Explain your reasoning:
 An
acidic solution contains an excess of
protons or H+.
 3.
Which has the highest
concentration of OH– ions?
 Seltzer,
baking soda, bar soap, antibacterial cleaner,
 Bar Soap is the greatest base!!
 4.
Explain your reasoning:
 Basic
solutions release OH- ions in a
solution.
Red cabbage juice
 5.
The red cabbage juice is used
in the Investigations has 2 roles:


pH indicator
control.
 Why
is a control needed on the pH
test plate?
 Control is the substance that stays
the same in each trial. It is used to
measure the differences between the
other solutions.
Mystery solutions A & B are identical to 2
other solutions you used in this lab. Use
your results to identify these solutions.
 1.
What is the identity of
mystery solution
 List
evidence to support your claim
 2.
What is the identity of
mystery solution B

List evidence to support your
claim:
 Claim
A
statement about the
solution to the problem (a
statement of hypothesis).
Evidence
 The
scientific data that supports
the claim.
Reasoning
 Justification
that shows why the
data counts as evidence to
support the claim. It includes
appropriate scientific principles.