Chapter 4 - Acids and Redox

Question 1

What is an acid?

Answer 1

When dissolved in water, it will release hydrogen ions as protons into the solution.

Question 2

What is a strong acid?

Answer 2

Releases all of its hydrogen atoms into solution.

It completely dissociates in aqueous solution.

Question 3

What is a weak acid?

Answer 3

Releases a small proportion of its available hydrogen atoms into solution.
It partially dissociates in aqueous solution.

Question 4

What is a base?

Answer 4

A base neutralises an acid to form a salt.

Question 5

what are some examples of bases?

Answer 5

there are several types of bases

metal oxides
metal hydroxides
metal carbonates
alkalis

Question 6

What is an alkali?

Answer 6

A base that dissolves in water releasing hydroxide ions into the solution.

Question 7

What is the word equation for the neutralisation of acids with metal oxides/hydroxides?

Answer 7

Metal oxide/hydroxide + acid -> salt + water

Question 8

What is the word equation for the neutralisation of acids with alkalis?

Answer 8

Acid + alkali -> salt + water

Question 9

ammonia + acid = ?

Answer 9

ammonia ,NH3 reacts with acds by accpeting H+ to form ammonium salts containg an ammonium ion

e,g

HCL + NH3 = NH4Cl

Question 10

What is the word equation for the neutralisation of acids with carbonates?

Answer 10

Carbonate + acid -> salt + water + carbon dioxide

Question 11

What is a titration?

Answer 11

A technique used to accurately measure the volume of one solution that reacts exactly with another solution.

Question 12

What are titrations used for?

Answer 12

titrations are used for Finding the concentration of a solution.
Identification of unknown chemicals.
Finding the purity of a substance.

Question 13

What are concordant results?

Answer 13

Within 0.10 cm^3 of each other.

Question 14

how to prepare a standard solution? 2 steps for NaOH

Answer 14

step 1: find mass of NaOH you want
step2:
weigh NaOH you need
dissolve NaOH, with stirring, in distilled water
pour solution into volumetric flask
rinse beaker with distilled water into the flask
add distilled water to flask - bottom of meniscus on graduation line
place stopper on flask and invert

Question 15

When can a mean titre be worked out?

Answer 15

When two or more concordant results are obtained.

Question 16

In an acid base titration, what rule is used to determine a solution’s concentration?

Answer 16

n(1)=n(2)

c(1)V(1)=c(2)V(2)

Question 17

When is the oxidation number zero?

Answer 17

For elements on their own or bonded to atoms of the same element.

Question 18

What is the common oxidation number of oxygen?

Answer 18

-2

Question 19

What is the common oxidation number of hydrogen?

Answer 19

+1

Question 20

What is the common oxidation number of fluorine?

Answer 20

-1

Question 21

What is the common oxidation number of Na+ or K+?

Answer 21

+1

Question 22

What is the common oxidation number of Mg2+ or Ca2+?

Answer 22

+2

Question 23

What is the common oxidation number of other halides?

Answer 23

-1

Question 24

In what special case, can hydrogen have an oxidation number of -1?

Answer 24

When in metal hydrides.

i.e. NaH or CaH(2)

Question 25

In what special case, can oxygen have an oxidation number of -1?

Answer 25

In peroxides. | i.e. H(2)O(2)

Question 26

In what special case, can oxygen have an oxidation number of +2?

Answer 26

When bonded to fluorine. | i.e. F(2)O

Question 27

In ions, what is a trick for determining oxidation numbers?

Answer 27

The sum of the oxidation numbers, is equal to the total charge.

Question 28

What do roman numerals mean in the use of iron(II) or iron(III)?

Answer 28

Iron(II) represents Fe2+ with oxidation number +2. | Iron(III) represents Fe3+ with oxidation number +3.

Question 29

What is oxidation?

Answer 29

The loss of electrons.

Question 30

What is reduction?

Answer 30

The gain of electrons.

Question 31

What is oxidation in terms of oxidation number?

Answer 31

An increase in oxidation number.

Question 32

What is reduction in terms of oxidation number?

Answer 32

A decrease in oxidation number.

Question 33

What is the word equation for the reaction of a metal with acid?

Answer 33

Metal + acid -> salt + hydrogen