CHEM 12.1-12.3

Question 1

pure substance

Answer 1

single element of compound not mixed with any other substance

Question 2

what is used to distinguish pure substances and mixtures

Answer 2

melting and boiling point

Question 3

everyday language pure element

Answer 3

a pure substance can mean a substance that has nothing added to it, unadulterated and in its natural state.

Question 4

impure substance

Answer 4

melting point lowers and boiling point increases

Question 5

formulations

Answer 5

a mixture that has been designed as a useful product. Many products are complex mixtures in which each chemical has a particular purpose.

Question 6

how are formulations made?

Answer 6

mixing the components in carefully measured quantities to ensure that the product has the required properties

Question 7

what are examples of formulations?

Answer 7

fuels, cleaning agents, paints, medicine, foods

Question 8

what is chromotography used for

Answer 8

to separate mixtures and can give information to help identify substances.

Question 9

Rf value

Answer 9

distance moved by substance/distance moved by solvent

Question 10

how can you identify compounds in chromotography

Answer 10

differebt compounds have diff rf values so identify compounds

Question 11

mobile phase

Answer 11

solvent

Question 12

stationary phase

Answer 12

chromo paper

Question 12

chromotography uses two phases

Answer 12

the stationary phase is attracted to the paper

that mobile phases is soluble in the solvent

Question 13

test for oxygen

Answer 13

glowing splint in steered into test tube with gas. The splint relights in oxygen

Question 13

test for hydrogen

Answer 13

burning splint held at opening of test tube and squeaky pop

Question 14

test for chlorine

Answer 14

uses damp litmus paper and when turns white then chlorine present

Question 14

Test for carbon dioxide

Answer 14

uses limewater. When carbon dioxide is shaken with or bubbles through limewater the limewater turns cloudy