Atomic structure

Question 1

What is an atom?

Answer 1

An atom is the smallest part of an element that can exist

Question 2

What is an element?

Answer 2

An element is a substance of only one type of atom

Question 3

How are the elements listed and approx. how many are there?

Answer 3

They are listed in the periodic table - there are aprox. 100

Question 4

elements can be classified into two groups based on their properties ; what are these groups?

Answer 4

Metals and non metals

Question 5

elements may combine through chemical reactions to form new products; what are these new substances called?

Answer 5

compounds

Question 6

what is a compound?

Answer 6

two or more elements combined chemically in fixed proportions which can be represented by formulae

Question 7

Do compounds have the same properties as their constitutent elements?

Answer 7

no, they have different properties

Question 8

what is a mixture?

Answer 8

a mixture consists of two or more elements or compounds not chemically combined together

Question 9

Do mixtures have the same chemical properties as its constitutent materials?

Answer 9

yes

Question 10

what are the methods through which mixtures can be seperated? (5)

Answer 10

• filtration
• crystillisation
• simple distilliation
• fractional distilliation
• chromotography

Question 11

Do the methods that mixtures can be seperated involve chemical reactions?

Answer 11

no

Question 12

describe and explain simple distilliation

Answer 12

simple distilliation is used to seperate liquid from a solution - the liquid boils off and condenses in the condenser. The thermometer will read the boiling point of the pure liquid. Contrary to evapouration, we get to keep the liquid

Question 13

describe and explain evapouration

Answer 13

Evapouration is a technique for seperation of a solid dissolved in a solvent from a solvent (eg. salt from water)
the solution is heated until all the solvent evapourates; the solid stays in the basin