c12 chemical anylasis

Question 1

what is a pure substance

Answer 1

PURE substance = one that is made up of only one substance - can be an element or compound

Question 2

what are the boiling point an melting points called

Answer 2

the MP/BP of a pure substance = its fixed points

Question 3

does a mixture have fixed points

Answer 3

a mixture (NOT pure) does not have fixed points as it changes state over a range of temperatures

Question 4

what happens to the boiling point and melting point if there are impurities in the mixture

Answer 4

Impurities in a pure substance lowers its MP and increases the BP - the more impurities there are, the bigger the change in MP/BP

Question 5

what is a formulation

Answer 5

Formulation = a mixture designed to produce a useful product

Question 6

name some formulations

Answer 6

An example of a formulation is paint medicines and washing up liquid

Question 7

what does paint contain

Answer 7

in general, paint contains:
a pigment - to give it colour
a binder - to help the pain attach itself to an object
–> also to form a protective film when dry
3. a solvent - thins pigment and binder to help them spread easier

Question 8

why are medicines considered formulations

Answer 8

medicinal drugs are also formulations –> normally only contains 5-10% of the active drug

Question 9

what does washing up liquid contain

Answer 9

washing up liquids:
rinse agent - helps water drain off crockery
colouring and fragrance additives –> appeal
water –> thins out the mixture for easier squirting
surfactants - actual detergent that removes grease

Question 10

what is the mobile phase

Answer 10

Mobile phase: solvent

Question 11

what is the stationary phase

Answer 11

Stationary phase: paper

Question 12

what is solubility

Answer 12

solubility = how easily a solute dissolves into a solvent

Question 13

what does the distance travelled by the dyes depend on

Answer 13

the solubility
the attraction to the paper

Question 14

what does it mean if there’s one spot at the end

Answer 14

if there’s only one spot at the end that indicates that it is a pure substance

Question 15

what is the rf value

Answer 15

Rf value = retention factor

Question 16

what is the equation for rf

Answer 16

Rf = distance moved by substance
distance moved by solvent

Question 17

how do we get hydregon

Answer 17

To get the hydrogen gas: SQUEAKY POP TEST
Zn (s) + H2SO4 (aq) –> ZnSO4(aq) + H2(g)

Question 18

how can you increase the rate of the reaction to get hydrogen

Answer 18

To produce the gas faster, you can add a few crystals of copper(II) sulfate

Question 19

what is the test for hydregon

Answer 19

Place a lighted splint in hydrogen - the flame should go out with s squeaky pop

Question 20

how can we get oxygen

Answer 20

to get oxygen gas:
the thermal decomposition of hydrogen peroxide
2H2O2 (aq) –> 2H2O (l) + O2(g)

Question 21

how can you increase the rate of the reaction to get oxygen

Answer 21

Catalyst for this reaction = manganese (IV) oxide

Question 22

what is the test for oxygen

Answer 22

In oxygen, a glowing splint relights

Question 23

how do we get carbon dioxide

Answer 23

To get carbon dioxide:
react marble chips with dilute hydrochloric acid
CaCO3(s) + 2HCl (aq) –> CaCl2 (aq) + H2O(l) + CO2(g)

Question 24

what is the test for carbon dioxide

Answer 24

2. When passing CO2 through limewater, the limewater should go from clear to cloudy

Question 25

what is the test for chlorine

Answer 25

n Chlorine gas, damp blue litmus paper turns white (as if it gets bleached)