Then it is possible to measure accurately the weight of it, so you know exactly how many moles of the primary standard you have. When it would have been hygroscopic then your actual mass of the standard is lower than the measured, caused by the extra weight of water.
Sodium Carbonate (Na2CO3) is most commonly used to standardise acids as it is non-hygroscopic (doesn't absorb water from the atmosphere).Oxalic Acid (HOOCCOOH or H2C2O4) used to standardise bases
In crystalline form it's non-hygroscopic, or has only slight hygroscopicity. In powder form it is, yes.
KHP (potassium hydrogen phthalate) is available extremely pure (which is always good for a primary standard) and gives a very sharp end-point especially with Crystal Violet Indicator
No. Chemical compounds have to fulfill a number of requirements before they can be classified and used as a primary standard: A primary standard in chemistry is a reliable, readily quantified substance. Features of a primary standard include: 1. High purity 2. Stability (low reactivity) 3. Low hygroscopicity and efflorescence 4. High solubility (if used in titration) 5. High equivalent weight 6. Non-toxicity 7. Ready and cheap availability Edta and particularly the sodium salts of EDTA which are frequently used do not fulfill the first requirement. Therefore the solution of EDTA has to be standardised against a known and accepted primary standard.
cause you dont have a weener
Non-Hygroscopic
Sodium Carbonate (Na2CO3) is most commonly used to standardise acids as it is non-hygroscopic (doesn't absorb water from the atmosphere).Oxalic Acid (HOOCCOOH or H2C2O4) used to standardise bases
Titrate it with a primary standard
In crystalline form it's non-hygroscopic, or has only slight hygroscopicity. In powder form it is, yes.
non granted school
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KHP (potassium hydrogen phthalate) is available extremely pure (which is always good for a primary standard) and gives a very sharp end-point especially with Crystal Violet Indicator
No. Chemical compounds have to fulfill a number of requirements before they can be classified and used as a primary standard: A primary standard in chemistry is a reliable, readily quantified substance. Features of a primary standard include: 1. High purity 2. Stability (low reactivity) 3. Low hygroscopicity and efflorescence 4. High solubility (if used in titration) 5. High equivalent weight 6. Non-toxicity 7. Ready and cheap availability Edta and particularly the sodium salts of EDTA which are frequently used do not fulfill the first requirement. Therefore the solution of EDTA has to be standardised against a known and accepted primary standard.
primary and non primary
primary and non primary
Whenever you use any non-standard definition.Whenever you use any non-standard definition.Whenever you use any non-standard definition.Whenever you use any non-standard definition.
A non-key field can be any field in the table that is not the primary key. During the process of normalisation identifying non-key fields is important, as they and other fields may be moved and new tables created. Foreign keys will be left in the table.