C8 Chemical analysis Flashcards Preview

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Flashcards in C8 Chemical analysis Deck (41)
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1

What is a pure substance?

a substance with only 1 element/compound throughout

2

How can we test how pure a substance is?

we can compare MP/BP and the closer to the actual value, the purer it it.

3

What is the effect of impurities on the melting point?

impurities lower the melting point

4

What is the effect of impurities on the boiling point?

impurities increase the boiling point of a sample

5

what are formulations?

useful mixtures made of exact amounts of components

6

What is in the formulation of paint?

pigment
solvent
binder
additives

7

Why are formulations useful in the pharmacutical industry?

so chemists can ensure drugs are delivered to the correct part of the body, at the right concentration and has a long shelf life

8

What is chromatography?

a method to seperate the substances of a mixture

9

what are the 2 phases in chromatography?

a mobile phase
a stationary phase

10

how do you calculate the Rf value from chromatography?

distance travelled by substance
----------------------------------------------
distance travelled by solvent

11

What has to be done to make chromatography useful?

test a pure substance next to it so you can compare

12

What is the test for chlorine?

bleeches damp litmus paper white

13

What is the test for oxygen?

ignites a glowing splint

14

What is the test for carbon dioxide?

turns lime water (calcium hydroxide) cloudy

15

What si the test for hydrogen?

makes a squeaky pop when ignited with a lit splint

16

What are the 3 test for anions?

dilute acid-to test for carbonates
barium chloride and HCL- can test for sulphates
nitric acid and silver nitrate can test for halides

17

How can you test for carbonates?

add dilute acid and see if it turns limewater cloudy as co2 is released

18

How can you test for sulfates?

add a few drops on HCL and a few drops of barium chloride. a white precipitate will form if sulfate ions are present

19

How can you test for halides

add a few drops of nitric acid and silver nitrate.
the colour of precipitate determines the halide ion

20

In a halide ion test, what precipitates do chloride ions form?

white

21

In a halide ion test, what precipitates do bromide ions form?

cream

22

In a halide ion test, what precipitates do iodide ions form?

yellow

23

What colour flame to lithium ions burn with?

crimson

24

What colour flame to sodium ions burn with?

yellow

25

What colour flame to potassium ions burn with?

lilac

26

What colour flame to calcium ions burn with?

orange-red

27

What colour flame to copper ions burn with?

green

28

Why do you clean the loop in HCL in flame tests?

to ensure the loop isnt contaminated

29

What is a disadvantage of flame tests?

you can only detect samples that contain a single metal ion and not a mixture

30

what 2 ways can you test for cations?

flame tests
adding NaOH