Definitions [7]
Define Analytical chemistry.
The branch of chemistry which deals with the study of the separation, identification, qualitative and quantitative determination of the compositions of different substances, is called analytical chemistry.
Define: Least count
The smallest quantity that can be measured by the measuring equipment is called the least count.
The error expressed as a percentage of the true or measured value of a quantity, used to determine the accuracy of a measurement, is called the percentage error.
The degree of closeness of a measured value to the true value, which increases as the error decreases, is called accuracy.
The molecular formula of a compound denotes the actual number of atoms of different elements present in one molecule of the compound.
Define Stoichiometry.
The study of quantitative relations between the amount of reactants and/or products is called stoichiometry.
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Unsaturated solution: If the amount of solute contained in a solution is less than the saturation level, it is called an unsaturated solution. (till it is dissolving).
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Saturated solution: When no more solute can be dissolved in a solution at a given temperature, it is called a saturated solution.
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Solubility: The amount of the solute present in the saturated solution at this temperature is called its solubility.
Formulae [4]
If the error in a is Δa and in b is Δb, then:
Percentage error in \[\frac {a}{b}\] = \[\left(\frac{\Delta a}{a}+\frac{\Delta b}{b}\right)\times100\]
If the error in a is Δa, then:
Percentage error in a = \[\frac {Δa}{a}\] × 100
If the error in a is Δa, then:
Percentage error in an = ±n × \[\frac {Δa}{a}\] × 100
If the error in a is Δa and in b is Δb, then:
Percentage error in ab = \[\left(\frac{\Delta a}{a}+\frac{\Delta b}{b}\right)\times100\]
Theorems and Laws [1]
- The smaller the error, the greater the accuracy.
- For both product and division of two quantities, the percentage errors in the individual quantities are always added (never subtracted) to get the total percentage error.
