Topic 3 - Acids

Question 1

What does this symbol mean ?…

Answer 1

• Oxidising
• Provides O₂ which allows materials to burn mor fiercely
• E.g. Liquid oxygen

Question 2

What does this symbol mean ?…

Answer 2

• Highly Flammable
• Catches fire easily
• E.g. Petrol

Question 3

What does this symbol mean ?…

Answer 3

• Toxic
• Can cause death either by swallowing or breathing in, or absorption through skin
• E.g. Hydrogen cyanide

Question 4

What does this symbol mean ?…

Answer 4

• Harmful
• Like toxic but not quite as dangerous
• E.g. Copper sulfate

Question 5

What does this symbol mean ?…

Answer 5

• Irritant
• Not as corrosive but can cause redding or blistering of the skin
• E.g. Bleach

Question 6

What does this symbol mean ?…

Answer 6

• Corrosive
• Attacks and destroys living tissues including eyes and skin
• E.g. Concentrated sulfuric acid

Question 7

What is an acid ?

Answer 7

A substance at pH 0 to 6

E.g. Vinegar, Acid rain, Normal rain, Lemon juice

Red to yellow on the universal indicator

Question 8

What is a neutral ?

Answer 8

pH 7

E.g. Pure water

Green on the universal indicator

Question 9

What is a Alkali?

Answer 9

A base at pH 8 to 14

E.g. Ammonia, Oven cleaner

Blue to purple on the universal indicator

Question 10

What is the equation for a neutralisation reaction ?

Answer 10

Acid + Base > Salt + Water

Question 11

What acid does your stomach produce and what is it’s use?

Answer 11

HCl - Hydrochloric acid

Helps with digestion and kills bacteria

Indegestion is caused by too much HCl and bases in tablets neutralise the excess acid

Question 12

What 2 types ofmetals are usually indegestion remedies?

Answer 12

1. Mydroxides
2. Carbonates

Question 13

What to metal hydroxide/oxides produce when reacted with an acid?

Answer 13

Salt + Water

Question 14

What to metal carbonates produce when reacted with an acid?

Answer 14

Salt + Water + Carbon Dioxide

Question 15

How do you work out thesalt which is produced during a Acid + Base = Salt + water reaction ?

Answer 15

Hydrochloric acid + _*coppe*r_ oxide = copperchloride + water

Sulfuric acid + zinc*** oxide = ***zinc sulfate + water

Nitric acid + Magnesium*** oxide = ***Magnesium nitrate + water

Question 16

What does electrolysis mean ?

Answer 16

The breaking down (decomposition) of a compound using electrical energy

Splitting up electricty

Question 17

What does electrolysis need ?

Answer 17

• Direct current (D.C.)
• A liquid to conduct the electricity
• two electrodes

Question 18

If you use Electroylsis to break down HCl what are the two components you get?

Answer 18

• Hydrogen gas (H₂)
• Chlorine gas (Cl₂)

Question 19

What is the test for Hydrogen?

Answer 19

• A lighted splint into a test tube with the gas
• If hydrogen is present you will hear a squeaky pop

Question 20

What is the test for chlorine?

Answer 20

Into a solution in a test tube put in damp litmus paper

It will turn white if chlorine is present

And it may breifly turn red as chlorine is acidic

Question 21

What is the test for oxygen ?

Answer 21

Checking if the gas in a test tube relights a glowing splint

Question 22

What does the electrolysis of salt produce and what are its uses?

Answer 22

• Chlorine

Uses of chlorine:

• Treat water suplies by killing bacteria and other microorganisms
• Manufacture bleach
• Make the polymer - poly(chloroethene) - PVC

Question 23

What does the electroylsis of Water produce?

Answer 23

Hydrogen gas

Oxygen gas