Chemistry

Question 1

Which ion makes solutions acidic

Answer 1

Hydrogen ion
H+ (aq)

Question 2

Describe how to test a solution to show it is acidic

Answer 2

Add universal indicator to the solution, it will turn red/orange/yellow

Question 3

How does the pH of an acidic solution change if it becomes less acidic

Answer 3

The pH will increase

Question 4

What type of chemical reaction occurs when a metal hydroxide is added to an acid

Answer 4

Neutralisation reaction

Question 5

Which equation is used to work out the concentration solution in g/dm3

Answer 5

Concentration (g/dm3) =mass (g)/ volume (dm3)

Question 6

How do you convert a volume in cm3 to a volume in dm3

Answer 6

Divide by 1000

Question 7

Any method should identify key variables and what equipment you will use to measure the variables. What are the three key variables in an investigation

Answer 7

INDEPENDENT VARIABLE ( the variable we change and select different values of)

DEPENDENT VARIABLE (the variable we measure and record in a results table)

CONTROL VARIABLE (the variable we measure and meet the same throughout the investigation)

Question 8

Which piece of equipment would you use to measure the mass of a chemical

Answer 8

Top pan balance

Question 9

Which piece of equipment would you use to measure put a volume of gas produced in an experiment

Answer 9

Measuring cylinder

Question 10

Which piece of equipment can you use to record the volume of gas produced in an experiment

Answer 10

Gas syringe

Question 11

What observation can be made when hot sodium burns in oxygen gas

Answer 11

Yellow flame
White smoke
White powder left at the end of the

Question 12

What is the order of discovery of the electron, proton and neutron

Answer 12

1. Electron
2. Proton
3. Neutron

Question 13

How do you work out the number of neutrons in an atom from the mass number and atomic number

Answer 13

Mass number minus atomic number

Question 14

How can you calculate the relative atomic mass of an element from the mass numbers and percentage abundance of its isotopes

Answer 14

Mass number X percentage abundance
Divided by 100

Question 15

Explain why solid sodium chloride does not conduct electricity

Answer 15

Ions are not free to move

Question 16

What can we do to solid sodium chloride to allow it to conduct electricity

Answer 16

Dissolve in water to make a solution
Melt the solid

Question 17

What element is used to make inherit electrodes in electrolysis

Answer 17

Carbon

Question 18

What is the half equation to produce chlorine during electrolysis

Answer 18

2Cl- (arrow) Cl2 + 2e-

Question 19

What ions are present in sodium chloride solution

Answer 19

Sodium ions (Na+), chloride ions (Cl-), hydrogen ions (H+), hydroxide ions (OH-)

Question 20

What products are produced when sodium chloride solution is electrolysed

Answer 20

positive electrode: CHLORINE GAS
negative electrode: HYDROGEN

sodium ions join with hydroxide ions to form an alkaline solution of sodium hydroxide

Question 21

How do you work out the number of moles of a substance from its mass and relative formula mass (Mr)

Answer 21

Moles= mass (g)/Mr

Question 22

Which structures contain hexagonal rings

Answer 22

Graphite
Fullerenes
Graphene

Question 23

Why do metals allow the conduction of thermal energy

Answer 23

Delocalised electrons move through the structure and transfer energy

Question 24

Explain why ionic compounds like metal oxides have high melting points

Answer 24

Giant structure
Lots of strong forces of attraction between
oppositely charged ions
Lots of energy to break lots of bonds

Question 25

Why do simple covalent bonds molecules have low melting points

Answer 25

Made of small molecules
Weak forces between the molecules
Little energy needed to break the weak forces