Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Chemistry (Tara) > Volumetric Analysis > Flashcards

Volumetric Analysis Flashcards

1
Q

What does the moles of solute after dilution equal?

A

The moles of solute before dilution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What do you change and not change when you add water and dilute the solution?

A
  • change concentration

- do not change the moles of solute

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What can colour intensity be measured by?

A

Using a colorimeter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does the colour intensity dependent on?

A

The concentration of the solution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Define standard solution

A

A standard solution of know concentration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Define primary standard

A

A primary standard is a substance (solute) that can be made up to a standard solution directly as it is available in 100% purity, is stable in air, has a high molar mass of accuracy in weighing and dissolves easily in water.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Is a titration always needed to find a concentration?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the only two examples of primary standards that are used in the syllabus?

A
  • Anhydrous Na2CO3 (base), ammonium iron

- Sulphate (reducing agent)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Define secondary standard

A

A secondary standard is a substance(solutes) that cannot be made up to a standard solution directly as it is not available in 100% purity, or is not stable in air, or has a low molecular mass and does not dissolve readily in water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Define standardise

A

To standardise is to find out the concentration of a solution by titration or colorimetry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the first step in preparing a solution?

A

Solute (if solid is weighed accurately on a clock glass using an electronic balance.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What happens after the solute is weighed accurately on a clock glass?

A

All of the solute is transferred to a volumetric flask and made up to an accurately known volume e.g 250cm3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Why is the solute made up to an accurately known volume?

A
  • so the concentration can be calculated

- so there is enough solution to carry out 3 titrations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What happens first to the solute if it is solid?

A

Tipped into a beaker

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the clock glass washed with?

A

Deionised water from a wash-bottle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens after the clock glass is washed with deionised water?

A

The rinsings are added to the beaker and stirred with a clean dry glass rod until it dissolves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What happens after the rinsings are added to the beaker?

A

The solution is poured into the volumetric flask with the aid of a funnel to prevent spillage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What happens after the solution is added to the volumetric flask?

A

The funnel is removed and deionised water is added to the flask until the level of the solution is 1cm3 below the mark on the neck of the flask

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

When do you stop adding the deionised water drop by drop to the volumetric flask?

A

Until the bottom of the meniscus is on the graduation mark and read at eye-level

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What does the solution in the flask have after the deionised water is added?

A

A concentratinon gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is done near the end to make the solution homogenous?

A

The flask is stoppered, inverted 20-30 times and shaken to make the solution homogenous

22
Q

Why does the volumetric flask have a narrow neck?

A

To make the measurement accurate and able to see the bottom of the meniscus clearly.

23
Q

What is used to measure out an exact volume if the solute is in liquid form (bleach or vinegar)?

A

A properly rinsed pipette

24
Q

How is the solute transferred to the volumetric flask if its in liquid form?

A

By touching the tip of the inside of the volumetric flask

25
Q

What is the apparatus needed to prepare a standard solution of sodium carbonate? (not a titration)

A
  • Safety glasses
  • 250cm3
  • Volumetric flask
  • Beaker
  • Funnel
  • Glass rod
  • Dropper
  • Electronic balance
  • Wash bottle
26
Q

Materials needed to prepare a standard solution of sodium carbonate? (not a titration)

A
  • 2.65g of sodium carbonate

- Deionised water

27
Q

volumetric analysis

A

reacting 2 solutions together to find the concentration of one of them

28
Q

to find the concentration what information do you need to have

A

amount of solute

amount of solution

29
Q

pwv or %w/v

A

percentage weight per volume

grams per 100 cm cubed

30
Q

pww or %w/w

A

grams per 100 cm cubed

31
Q

pvv or %v/v

A

cm cubed per cm cubed

32
Q

ppm

A

parts per million

milligrams per litre

33
Q

M

A

molarity

moles per litre

34
Q

why is the pipette used for solutions at room temperature only?

A

liquids expand on heating and contract on cooling

35
Q

how do you clean the pipette?

A

first with deionised water and then the solution that it will contain

36
Q

what do you use to fill the pipette

A

a pipette filler

37
Q

why do you use a pipette filler

A

as solutions may be poisonois

38
Q

how do you fill the pipette?

A

draw the solution above the graduation mark and run out until the bottom of the meniscus reaches the zero mark, read at eye level

39
Q

how is the solution transferred from a pipette? why?

A

by touching the tip off the inside of the flask, this ensures the exact volume is transferred

40
Q

do you blow the last drop out of the pipette? why?

A

no, it is accounted for in the calibration of the pipette

41
Q

what is the function of the narrow neck on the conical flask?

A

prevents spillage during swirling

42
Q

what is the function of the conical flask in a titration?

A

this is the vessel in which the two solutions will react

43
Q

what do you wash the conical flask with and why?

A

only deionised water as not to change the number of moles of solute taking part in the reaction

44
Q

how accurate does the burette measure?

A

to 0.1 cm cubed accuracy

45
Q

how is the burette clamped and why?

A

clamped vertically to avoid the error of parallax

46
Q

where does the acid USUALLY go?

A

the burette

47
Q

where does the base USUALLY go?

A

the pipette

48
Q

what do you wash the burette with before the titration and why?

A

deionised water and then the solution it will contain. water droplets would dilute the solution

49
Q

how do you fill the burette

A

close tap, add a funnel, fill above zero graduation mark, remove funnel, add a waste beaker underneath. read at eye level, open tap until the bottom of the meniscus reaches the zero graduation mark.

50
Q

one liquid that is read from the top of the meniscus in the burette and why

A

KMnO4 because of its deep purple colour

Chemistry (Tara) (50 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions