Chem

Question 1

What is an element

Answer 1

When all of the atoms are the same

Question 2

Compounds contain…..

Answer 2

Two or more different elements chemically combined

Question 3

How do you separate a compound back into its element how do you do this

Answer 3

Chemical reaction

Question 4

What is a mixture

Answer 4

A mixture is a substance made of different elements or compounds but not chemically combined

Question 5

How do you separate mixtures

Answer 5

Filtration
Distillation
Crystallisation

Question 6

What is a molecule

Answer 6

A molecule has any element chemically combined

Question 7

What does the chemical formula tell us for the compound

Answer 7

A chemical formula tells us the elements in a molecule and number of atoms

Question 8

When you have CaSO4 how many atoms do you have

Answer 8

Ca is (Calcium) and it has no small number next to it so it has (one atom)
Again the same with S(sulphur)
But with oxygen (O) it has a small 4 next to it so it has (4 atoms)

Question 9

Mg(OH)2

Answer 9

We have 3 elements
Mg( has one atom )
O ( has 2 oxygen because you x it by the number on the outside)
H ( hydrogen has 2 atoms too)

Question 10

What can physical separating techniques only be used to separate

Answer 10

Mixtures

Question 11

What is filtration used for

Answer 11

Used to separate an insoluble solid from a liquid

Question 12

What do state symbols tell us

Answer 12

They tell us the physical state of a chemical

Question 13

How do we filter an insoluble substance from a liquid

Answer 13

Conical flask
Filter funnel
Filter paper

Question 14

What is crystallisation used for

Answer 14

To separate a soluble solid from a liquid

Question 15

What is a solution in water called

Answer 15

Aqueous solution

Question 16

When would we use simple distillation

Answer 16

When you would want to separate a dissolved solid from a liquid but want to keep the liquid

Question 17

What are the two stages of simple distillation

Answer 17

1.) You evaporate liquid by heating the liquid by heating
2.) next condense the back to a liquid by cooling

Question 18

How can fractional distillation be used to separate mixtures

Answer 18

Fractional distillation is used to separate components that have different boiling points from a mixture

Question 19

If an element has different isotopes what does this mean

Answer 19

Each isotope of an element has the same number of protons and a different number of neutrons

Question 20

What happens to a metal atom and non metal atom when an ionic bond forms between them

Answer 20

The metal atom loses electrons to become positively charged ions

Question 21

What properties of metals make them all useful structural materials

Answer 21

Metals contain metallic bonds which are very strong.Mostly have high melting and boiling points

Question 22

Explain why most polymers are solids at room temperature

Answer 22

Because they are held together by strong covalent bonds

Question 23

Explain why electrolysis is an expensive way of extracting metals from their ores

Answer 23

Electrolysis requires a lot of heat and electrical energy

Question 24

What is carbon footprint

Answer 24

The amount of carbons dioxide produced by the full cycle of a product

Question 25

What is the purpose of a life cycle assessment

Answer 25

Provides a way of comparing different products to see which cause least damage to the environment