C5-chemical Changes

Question 1

What is the reactive series in order of reactivity

Answer 1

Potassium 
Sodium 
Lithium 
Calcium 
Magnésium 
Aluminium 
Zinc 
Iron
Tin
Lead 
Copper 
Silver 
Gold

Question 2

What can metals be placed in order of by their reactions with water and dilute acid

Answer 2

Reactivity

Question 3

What gas is given off if metals react with water or dilute acids. What

Answer 3

Hydrogen. The gas pops with a lighted spill

Question 4

What non metals can be given positions in the reactivity series on the basis of displacement reactions

Answer 4

Hydrogen and carbon

Question 5

What is oxidation and what is reduction

Answer 5

Oxidation is the loss of electrons and reduction is the gain of electrons

Question 6

What is a metal ore

Answer 6

A metal ore contains enough of the metal to make it economic to extract the metal. Ores are mined and might need to be concentrated before the metal is extracted and purified

Question 7

What does the reactivity series help you to decide?

Answer 7

The reactivity series helps you decide the best way to extract a metal from its ore. The oxides of metals below carbon in the series can be reduced by carbon to give the metal element.
Metals more reactive than carbon can not be extracted from their ores using carbon. They are extracted by electrolysis of the molten metal compound

Question 8

How do you make a salt from a metal

Answer 8

Metal + acid makes a salt + hydrogen

Metal must be above hydrogen

Question 9

What is a salt

Answer 9

A salt is a compound formed when the hydrogen in an acid is wholly or partially replaced by a metal it ammonium ions

Question 10

How can a sample of the salt (salts from metals) be made into a crystal

Answer 10

A sample of the salt made can be crystallised out of the solution by evaporating off the water

Question 11

What is an example of a redox reaction

Answer 11

The reaction between a metal and an acid. The metal atoms lose electrons and are oxidised and hydrogen ions from the acid gain electrons and are reduced

Question 12

What occurs when an acid reacts with a base?

And what is the formula for this?

Answer 12

Neutralisation reaction occurs

Acid+base makes a sale + water

Question 13

Formula for acid + alkali

Answer 13

Acid + alkali > a salt + water

Question 14

Reaction for acids + carbonates

Answer 14

Acid + carbonate > a salt + water + carbon dioxide

Question 15

What is needed when a soluble salt is prepared by reacting and alkali with an acid

Answer 15

An indicator. The titration can be repeated without the indicator to make a salt, then a pure, dry sample of its crystal prepared

Question 16

What are acids

What are bases

What is an alkali

Answer 16

Acids are substances that produce H+ (aw) ions when you add them to water

Bases are substances that will neutralise acids

An alkali is a soluble hydroxide. Alkalis produce OH- (aq) ions when you add them to water

Question 17

What can you use the ph scale to show

Answer 17

You can use the ph scale to show how acidic or alkaline a solution is. If the solution has a ph value less than 7 than it is acidic, pH values not than 7 are alkaline and a pH value of 7 indicates a neutral solution. Oh

Question 18

What do aqueous solutions of weak acids such as carboxylic acid have a higher ph value than

Answer 18

The solutions of strong acids with the same concentration

Question 19

As the pH decreased by one unit, what does the hydrogen ion concentration of the solution increase by

Answer 19

A factor if 10