Elements, Mixtures and Compounds

Question 1

When do Chemical changes occur?

Answer 1

When Chemical reactions between two elements happen, creating a new substance. They involve the creation of compounds

Question 2

What are Physical changes?

Answer 2

In a physical change, no substances are formed, instead, a change of state occurs or diffusion.

Question 3

What elements are in:

1Plastic
2Water
3Car
4Flower

Answer 3

1Hydrogen, Carbon
2Oxygen, Hydrogen
3Alluiminium, Iron, Silicon, Boron, Oxygen
4Oxygen, Hydrogen, Nitrogen, Carbon

Question 4

What is a molecule?

Answer 4

They are made when two atoms chemically combine. If atoms are from different elements, they create a compound. Helium particles are not molecules. Hydrogen, nitrogen and oxygen’s are.

Question 5

Atoms/Elements are…

Answer 5

Atom is the smallest particle. Found in Elements.
Elements are made of only one type of atom and cannot be split through chemical methods, though they can through electrolysis. There are 118

Question 6

Periodic Table

Answer 6

Columns = groups - link elements with similar properties

Question 7

Hidrogen

Answer 7

H, A NM

Question 8

Lithium

Answer 8

Li, a metal

Question 9

Helium

Answer 9

He, a NM

Question 10

Beryllium

Answer 10

Be, a metal

Question 11

Boron

Answer 11

B, a metal

Question 12

Carbon

Answer 12

C, a nm

Question 13

Nitrogen

Answer 13

N, a nm

Question 14

Oxygen

Answer 14

O, a nm

Question 15

Fluorine

Answer 15

F, a nm

Question 16

Neon

Answer 16

Ne, a nm

Question 17

Sodium

Answer 17

Na, a metal

Question 18

Magnesium

Answer 18

Mg, a metal

Question 19

Aluminium

Answer 19

Al, a metal

Question 20

Silicon

Answer 20

Si, a nm

Question 21

Phosphorus

Answer 21

P, a nm

Question 22

Sulfur

Answer 22

S, a nm

Question 23

Chlorine

Answer 23

Cl, a nm

Question 24

Argon

Answer 24

Ar, a nm

Question 25

Potassium

Answer 25

K, a metal

Question 26

Calcium

Answer 26

Ca, a metal

Question 27

1 iron/ 2 sulphur/ 3 iron sulphide is…

Answer 27

1brown grey, is magnetic and forms hydrogen with hydrochloric acid
2yellow, isn’t magnetic
3dark black, isn’t magnetic, Hydrogen sulfate formed with hydrochloric acid

Question 28

When burnt, magnesium

Answer 28

Changes from wire to powder as it reacts with oxygen

Question 29

Signs of a Chemical Reaction

Answer 29

*Light is given off
*change of colour
*heat is given off
* gas is given off
*smell is given off
*sound is given off

Question 30

Iron chloride, potassium

Answer 30

Bloody red

Question 31

Copper Sulphate/ammonia solution

Answer 31

Dark blue

Question 32

Coper Sulphate/zinc

Answer 32

Black

Question 33

Barium nitrate/sodium sulphate

Answer 33

Opaque white

Question 34

Iron sulphate/sodium hydroxide

Answer 34

Gold

Question 35

Barium nitrate/sodium hydroxide

Answer 35

Opaque purple

Question 36

Silver nitrate/iron sulphate

Answer 36

Extremely opaque

Question 37

Ammonia conadate/hydrochloric acid and zinc

Answer 37

White

Question 38

Why can’t chemical changes easily be reversed

Answer 38

As atoms from different elements have bonded, meaning that they have a different composition to before. For example, when magnesium is burnt, it turns into a powder, which can’t be easily a wire again

Question 39

Why doesn’t mass change in chemical/physical changes?

Answer 39

As no atoms are added or taken away throughout the change. The new substance created in chemical reactions is composed of the reactants’ atoms.