Module 9

Question 1

State whether the substance described is most likely an acid or a base:

a. A substance that tastes bitter
b. A substance that feels slippery
c. A substance that turns blue litmus paper red.

Answer 1

a. Base
b. Base
c. Acid

Question 2

Identify the acid in the following reaction:

PH3 + CH4O –> CH3O- + PH4+

Answer 2

CH4O

Question 3

Some books define a base as a Proton acceptor. Why is this just as correct a definition as the one presented in this book?

Answer 3

We define a base as a H+ acceptor, but an H+ ion is simply a proton.

Question 4

Which of the following is (are) polyprotic acid(s)?

a. HNO3 b. H2CO3 c. Ca(OH)2 d. H3PO4

Answer 4

b and d

Question 5

Which of the following units could be used as concentration units?
a. mL/meter b. grams/m3 c. moles/sec d. moles/mL

Answer 5

b and d

Question 6

A chemist want to make a solution of 3.4 M HCl. He can find 2 solutions of HCl on the shelf. One has a concentration of 6.0 M, while the other has a concentration of 2.0 M. Which solution can the chemist use to make the desired acid?

Answer 6

6.0 M

Question 7

When the compound Al2(CO3)3 dissolves in water, what ions does it form and how many of each ion are present?

Answer 7

2Al 3+ and 3CO3 2-

Question 8

Consider the following reactions:
HCO3- + NaOH –> Na+ +CO3 2- + H2O
H2O + HCO3 - –> H2CO3 + OH-
Which substance in the 2 equations is acting as an amphiprotic substance?

Answer 8

HCO3-

Question 9

In acid-base chemistry, what 2 uses does and indicator serve?

Answer 9

it can determine whether a substance is an acid or a base. It can also help us find the endpoint of a titration.

Question 10

In a titration, what is the significance of the endpoint?

Answer 10

It tells us that we have added just enough acid (or base) in our titration to eat up all of the base (or acid) in out unknown solution. (depending on if the unknown is an acid or a base).

Question 11

What is an acid that can give up more than one H+ ion?

Answer 11

Polyprotic acid.

Question 12

What is a thing that changes color when exposed to acids or bases?

Answer 12

an Indicator

Question 13

What is a compound that can act as both an acid and a base?

Answer 13

Amphiprotic

Question 14

What is the dilution equation?

Answer 14

M1V1 = M2V2

Question 15

What is dilution?

Answer 15

It is the process of adding water to a solution to decrease the concentration

Question 16

What are the characteristics of an Acid?

Answer 16

Acids taste sour
Acids are covalent compounds that conduct electricity when added to water
Acids turn blue litmus paper red

Question 17

What are the characteristics of a Base?

Answer 17

Bases taste bitter
Bases are slippery to the touch when dissolved in water
Bases turn red litmus paper blue

Question 18

What happens when an ionic compound dissolves?

Answer 18

it splits into their constituent ions.

Question 19

What is Molarity?

Answer 19

it is a concentration unit that tells how many moles of a substance are in a liter of solution.

Question 20

What is the Molarity equation?

Answer 20

moles/# liters

Question 21

Note:

Answer 21

If you take away a negative and add one there is no charge change… be careful with moving charges