experimental technique and chemical analysis

Question 1

solvent

Answer 1

a liquid substance within which a solute can dissolve

Question 2

solute

Answer 2

a soluble solid that has dissolved in a solvent

Question 3

suspension

Answer 3

a mixture of substances; usually a liquid that may or may not be a solution, and an insoluble solid

Question 4

residue

Answer 4

the insoluble solution that passes through the filter in filtration

Question 5

filtrate

Answer 5

the soluble solution which passes through the filter in filtration

Question 6

titration indicators

Answer 6

Phenolphthalein
Thymolphthalein
Methyl orange

Question 7

titration apparatus

Answer 7

• Volumetric pipette
• Burette
• Conical flask

Question 8

titration steps (7)

Answer 8

1. Using the volumetric pipette, add a fixed volume of the unknown solution to a conical flask
2. Add a few (2-3) drops of indicator (phenolphthalein)
3. Fill the burette with the known solution and make sure its leveled exactly at zero (meniscus)
4. Slowly add the solution from the burette to the solution in the conical flask. Swirl the flask whilst doing so
5. Do this until the color changes from bight pink to very light pink - the point of neutralization
6. Record the volume showing in the burette
7. Repeat this process without the indicator

Question 9

ammonia test and result

Answer 9

damp red litmus paper turns blue

Question 10

carbon dioxide test and result

Answer 10

limewater turns milky

Question 11

chlorine test and result

Answer 11

damp litmus paper bleaches white

Question 12

hydrogen test and result

Answer 12

lighted splint ignites with a pop

Question 13

oxygen test and result

Answer 13

glowing splint relights

Question 14

sulfur dioxide test and result

Answer 14

turns acidified aqueous potassium manganate(VII) from purple to colorless

Question 15

purification methods (3)

Answer 15

• Filtration
  
  • Used to separate an insoluble solid from a liquid within a suspension
  • Includes a filter funnel and a filter paper
• Crystallization
  
  • Method that allows pure crystals of a particular solid to be obtained from a solution as it cools
• Distillation
• separating technique used to separate liquids by temporarily transforming one of the liquids into a gas

Question 16

lithium (Li+) flame color

Answer 16

red

Question 17

sodium (Na+) flame color

Answer 17

yellow

Question 18

potassium (K+) flame color

Answer 18

lilac

Question 19

copper(II) (Cu2+) flame color

Answer 19

blue-green

Question 20

barium (Ba2+) flame color

Answer 20

light green

Question 21

calcium (Ca2+) flame color

Answer 21

orange-red