Unit 2A | Keeping up the Standards |RESUB
Keeping up the Standards
Preparing a standard solution | part 1 | 22/1/24
Introduction
A standard solution is a solution that has a precisely known concentration.
Usually measured in moldm-3. It is used to determine the accuracy and
precision of a test procedure.
Calculation (of amount required for Na2CO3)
Mr = Sum of relative atomic masses of the atoms in the numbers shown in
the formula
= (23 x 2) + 12 + (16 x 3) = 106
Concentration = Number of moles / Volume
= 0..25 = 0.1
Moles = Concentration x Volume
= 0.1 mol/dm3 x 0.25 dm3 = 0.025
Mass = Moles x Mr
= 0.025 x 106 = 2.65g
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,Unit 2A | Keeping up the Standards |RESUB
Procedure
Apparatus:
▪ 250cm3 Volumetric Flask = used to accurately measure out the volume
of the sodium carbonate solution inside.
▪ Beaker = to dissolve the solid inside and create a solution
▪ Weighing boat = to weigh out the correct amount of solid (Na2CO3)
▪ Glass rod = to stir the solution
▪ Top pan balance (2 d.p) = to measure the precise weight of the solid
needed
▪ Funnel = used to accurately and carefully transfer the sodium carbonate
solution from the beaker into the volumetric flask.
Method:
1. The required amount of sodium carbonate is measured using the top
pan balance.
2. The sodium carbonate is transferred into a beaker where it is dissolved
using distilled water.
3. The distilled water is used to wash out every part of the sodium
carbonate solution (that may be remaining on the equipments) into the
flask.
4. The solution is transferred into a volumetric flask ensuring that there are
no traces remaining inside the beaker.
5. More distilled water is added into the 250cm3 volumetric flask until the
bottom of the meniscus is aligned with the graduation mark.
6. The volumetric flask is capped securely and inverted several times to
allow the solution to be mixed thoroughly.
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, Unit 2A | Keeping up the Standards |RESUB
Risk Assessment
Hazard Risk Safety Measures
Sodium Carbonate 1 Corrosive, Irritation to • Wear lab gear to
(Bland, 2017) ensure protection.
eye and skin
• Do not bring close to
mouth or nose to
avoid inhalation.
• Avoid handling with
Top Pan Balance Electric Shock wet hands.
• Keep away from
liquids.
• Make sure plug is
fully inside the
socket.
Glassware Cuts • Wear lab gear
• Handle with care
• Report breakages to
teacher and dispose
of properly.
Sodium Carbonate Spillage, Irritation to • Handle carefully
Solution skin • Be standing to be
able to move out of
the way when a
spillage occurs.
• Report spillages to a
teacher
1. Source of Risk Assessment - Bland, L. (2017). Sodium Carbonate. [online] Available at:
https://www.borderjanitorial.co.uk/files/COSHH/SodiumCarbonate.pdf (Accessed 16/2/24).
3|P a g e
Keeping up the Standards
Preparing a standard solution | part 1 | 22/1/24
Introduction
A standard solution is a solution that has a precisely known concentration.
Usually measured in moldm-3. It is used to determine the accuracy and
precision of a test procedure.
Calculation (of amount required for Na2CO3)
Mr = Sum of relative atomic masses of the atoms in the numbers shown in
the formula
= (23 x 2) + 12 + (16 x 3) = 106
Concentration = Number of moles / Volume
= 0..25 = 0.1
Moles = Concentration x Volume
= 0.1 mol/dm3 x 0.25 dm3 = 0.025
Mass = Moles x Mr
= 0.025 x 106 = 2.65g
1|P a g e
,Unit 2A | Keeping up the Standards |RESUB
Procedure
Apparatus:
▪ 250cm3 Volumetric Flask = used to accurately measure out the volume
of the sodium carbonate solution inside.
▪ Beaker = to dissolve the solid inside and create a solution
▪ Weighing boat = to weigh out the correct amount of solid (Na2CO3)
▪ Glass rod = to stir the solution
▪ Top pan balance (2 d.p) = to measure the precise weight of the solid
needed
▪ Funnel = used to accurately and carefully transfer the sodium carbonate
solution from the beaker into the volumetric flask.
Method:
1. The required amount of sodium carbonate is measured using the top
pan balance.
2. The sodium carbonate is transferred into a beaker where it is dissolved
using distilled water.
3. The distilled water is used to wash out every part of the sodium
carbonate solution (that may be remaining on the equipments) into the
flask.
4. The solution is transferred into a volumetric flask ensuring that there are
no traces remaining inside the beaker.
5. More distilled water is added into the 250cm3 volumetric flask until the
bottom of the meniscus is aligned with the graduation mark.
6. The volumetric flask is capped securely and inverted several times to
allow the solution to be mixed thoroughly.
2|P a g e
, Unit 2A | Keeping up the Standards |RESUB
Risk Assessment
Hazard Risk Safety Measures
Sodium Carbonate 1 Corrosive, Irritation to • Wear lab gear to
(Bland, 2017) ensure protection.
eye and skin
• Do not bring close to
mouth or nose to
avoid inhalation.
• Avoid handling with
Top Pan Balance Electric Shock wet hands.
• Keep away from
liquids.
• Make sure plug is
fully inside the
socket.
Glassware Cuts • Wear lab gear
• Handle with care
• Report breakages to
teacher and dispose
of properly.
Sodium Carbonate Spillage, Irritation to • Handle carefully
Solution skin • Be standing to be
able to move out of
the way when a
spillage occurs.
• Report spillages to a
teacher
1. Source of Risk Assessment - Bland, L. (2017). Sodium Carbonate. [online] Available at:
https://www.borderjanitorial.co.uk/files/COSHH/SodiumCarbonate.pdf (Accessed 16/2/24).
3|P a g e
