Topic C4 - Chemical Changes Flashcards Preview

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Flashcards in Topic C4 - Chemical Changes Deck (24)
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1

What are the lowest and highest pHs?

0 and 14

2

What colour does an acid turn the universal indicator?
What colour does an alkaline turn the universal indicator?

Acid = red
alkalis = purple

3

Is an acidic pH low or high?
Is an alkaline pH low or High?

Acidic = low
alkali = high

4

What ions do acids form in water?

H+

5

What ion do alkalis form in water?

OH-

6

What is a base?

A substance with a pH larger than 7

7

What is pH measuring?

The concentration of hydrogen ions

8

For every decrease of 1 on the pH scale, does the concentration of H+ ions increase or decrease, and by how much?
What about for a decrease of 2?

When the pH decreases by 1 the concentration of H+ ions increases by a factor of 10
when the pH decreases by 2 the concentration of H+ ions increases by a factor of 100

9

What is the reactivity series?

Potassium
Sodium
Lithium
Calcium
Magnesium
Carbon
Zinc
Iron
Hydrogen
Copper

10

How can you tell the reactivity of a metal by reacting it with an acid?

The more reactive the metal the more bubbles will be given off at a faster rate. you can also tell by how much the temperature changed, and how long the reaction lasted (the faster it goes the more reactive the acid)

11

What do you get when you react an acid and a metal?

Salt and hydrogen

12

What do you get when you react a metal and water?

Metal hydroxide + hydrogen

13

What is the definition of an ore?

A metal oxide that is naturally found in rocks and contains enough metal to be economical to extract

14

What is the opposite of oxidation?

Reduction

15

Why can't some metals be extracted using carbon?

They are less reactive than carbon, so carbon can't displace them.

16

Oxidation and reduction are both examples of what type of reaction?

A redox reaction

17

What what is the name of the reaction that means 'splitting up with electricity'?

Electrolysis

18

If electrons are transferred, what type of reaction is it?

A redox reaction

19

Define a strong acid.
Define a weak acid.

A strong acid forms H+ ions and ionises fully in aqueous solutions.
A weak acid forms H+ ions but only partially ionises in aqueous solutions.

20

Define a concentrated acid.
Define a dilute acid.

A concentrated acid has a large amount of acid per unit volume. A dilute acid has a small amount of acid per unit volume.

21

Are metal oxides and hydroxides acidic or alkaline?

Alkaline

22

What does a reaction between an acid and a metal carbonate produce?

A salt, water and carbon dioxide

23

What does a reaction between an acid and a metal oxide produce?
What about with a metal hydroxide?

They both produce a salt and water.

24

What does a reaction between a metal and an acid produce?

A salt and hydrogen