AnswersTX-Chemistry B-CRLab: Measuring pH

Lab: Measuring pH — Unit test Answers

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A compound accepts electrons from another substance to form a covalent bond. Which term best describes this compound’s behavior?

A
Lewis acid
B
Arrhenius base
C
Bronsted-Lowry acid
D
Bronsted-Lowry base
2
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Which of these equations correctly expresses the self-ionization of water?

A
Upper H subscript 2 upper O superscript plus upper H subscript 3 upper O superscript plus double-headed arrow upper H subscript 2 upper O plus upper O upper H superscript minus.
Option A
B
Upper H subscript 2 upper O plus upper H subscript 2 upper O double-headed arrow 2 upper O upper H superscript minus.
Option B
C
Upper H subscript 2 upper o plus upper H subscript 2 upper O double headed arrow 2 upper H subscript 3 upper O superscript plus.
Option C
D
Upper H subscript 2 upper O plus upper H subscript 2 upper O double-headed arrow upper H subscript 3 upper O superscript plus, plus upper O upper H superscript minus.
Option D
3

A substance is dissolved in water and produces hydronium ions. This occurs when hydrogen ions move from the substance to associate with water molecules. Which term best matches the behavior of this substance?

A
Arrhenius base
B
Arrhenius acid
C
Bronsted-Lowry base
D
Bronsted-Lowry acid
4

How does litmus paper identify a base?

A
A base turns red litmus blue.
B
A base turns blue litmus red.
C
A base turns orange litmus red.
D
A base turns yellow litmus blue.
5

Four different solutions (I, II, III, and IV) are labeled on the pH scale below.Why would solution IV be considered the most concentrated base out of the four substances?

Question illustration
A
It has the highest concentration of hydrogen ions.
B
It has the highest concentration of hydronium ions.
C
It has the highest concentration of oxide ions.
D
It has the highest concentration of hydroxide ions.
6

What is the Arrhenius definition of a base?

A
A substance that increases H3O+ concentration when it is dissolved in water.
B
A substance that increases OH– concentration when it is dissolved in water.
C
A compound that donates protons.
D
A compound that accepts protons.
7

Why is citric acid added to food?

A
to add color
B
to add tartness
C
to add bitterness
D
to add sweetness
8

An acid is a substance that increases the concentration of H3O+ ions in solution. Look at the reaction below of phenol (C6H5OH) with water:Which reactant acts as an acid by contributing a H+ ion to create H3O+ in the chemical equation?

Question illustration
A
C6H5OH(aq)
B
H2O(l)
C
C6H5O–(aq)
D
H3O+(aq)
9

An unknown substance turns methyl orange solution red. This shows that the substance

A
is a base.
B
is water.
C
is an acid.
D
is an alkaloid.
10

Which characteristic best identifies an Arrhenius base?

A
It must donate electrons to form a covalent bond.
B
It must accept protons from an acid.
C
It must generate hydroxide ions in water.
D
It must form a conjugate acid after reacting.
11

Several substances are labeled on the pH scale below.Which substance has the lowest [H+] concentration but is still considered an acid?

Question illustration
A
milk
B
blood
C
gastric fluid
D
household lye
12

The pH of lemon juice at 298 K is found to be 2.32. What is the concentration of ions in the solution? Use .

Question illustration
A
1.05 times 10 to the negative 3 moles per liter.
Option A
B
4.79 times 10 to the negative 3 moles per liter.
Option B
C
2.09 times 10 squared moles per liter.
Option C
D
9.55 times 10 squared moles per liter.
Option D

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