Separating Mixture and Conservation of Mass

Question 1

What are the four state symbols and what do they stand for?

Answer 1

(s) solid
(l) liquid
(g) gas
(aq) aqueous

Question 2

What is an element?

Answer 2

A substance made up of only one type of atom

Question 3

What is a mixture?

Answer 3

A substance that contains several different substances that are not chemically bonded together

Question 4

What is a compound?

Answer 4

A substance made up of two or more different types of atoms chemically bonded together

Question 5

In everyday language what is a “pure” substance?

Answer 5

A substance that has had nothing added to it and is in its “natural” state

Question 6

In chemistry what is a “pure” substance?

Answer 6

A substance made of a single element or compound

Question 7

How can pure substances be distinguished from impure ones?

Answer 7

By their melting/boiling points

Question 8

What are the melting and boiling points of pure substances?

Answer 8

One very specific temperature

Question 9

What are the melting and boiling points of impure substances?

Answer 9

They change state at a range of temperatures

Question 10

What is a formulation?

Answer 10

A mixture made to a specific recipe and designed for a specific purpose

Question 11

Give three examples of formulations.

Answer 11

Any three from: paint, detergents, medicines, cosmetics

Question 12

What type of mixture can be separated by filtration?

Answer 12

A liquid and an insoluble solid

Question 13

What is crystalliasation?

Answer 13

A process where water is evaporated from a solution to produce solid crystals of the substance dissolved

Question 14

What is distillation?

Answer 14

A process that separates a liquid from a solution (or mixture of liquids) by evaporating and then condensing the liquid

Question 15

What is fractional distillation?

Answer 15

A process to separate a mixture of liquids that have similar boiling points

Question 16

What is chromatography?

Answer 16

A process to separate the constituents of a mixture

Question 17

How can chromatography show the difference between pure and impure substances?

Answer 17

Pure ones will not separate into a number of spots

Question 18

In chromatography, why must the substances be placed on a pencil line?

Answer 18

Pencil will not dissolve in the solvent

Question 19

In chromatography why must the solvent height be lower than the pencil line?

Answer 19

So that the substances do not dissolve into the solvent off the paper

Question 20

What is the conservation of mass?

Answer 20

That atoms cannot be created or destroyed

Question 21

When a metal forms a metal oxide, why does the mass increase?

Answer 21

Because oxygen atoms from the air have been added

Question 22

When an acid reacts with a metal, why does the mass decrease?

Answer 22

Because a gas is produced and escapes