A 19.51 ݃ sample of impure methylamine, which contains 72.58% (by mass) of CH3NH2 , is reacted with 30.81 ݃ of pure oxygen gas: 4CHଷNHଶ(g) + 9Oଶ(g) ⟶ 4COଶ(g) + 10HଶO(ℓ) + 2Nଶ(g) In another experiment, this impure methylamine was used as follows: An unknown mass of the impure compound is dissolved in enough water to make 500.0 ݉ܮ of solution. 20 ݉ܮ of this solution was transferred by pipette to a clean 250 mL volumetric flask and made up to the mark. The molarity of the CH3NH2 in the final solution was determined to be 0.103 M. Determine the mass of CH3NH2 present in the original amount of impure compound used to make this solution.
Thermochemistry
Thermochemistry can be considered as a branch of thermodynamics that deals with the connections between warmth, work, and various types of energy, formed because of different synthetic and actual cycles. Thermochemistry describes the energy changes that occur as a result of reactions or chemical changes in a substance.
Exergonic Reaction
The term exergonic is derived from the Greek word in which ‘ergon’ means work and exergonic means ‘work outside’. Exergonic reactions releases work energy. Exergonic reactions are different from exothermic reactions, the one that releases only heat energy during the course of the reaction. So, exothermic reaction is one type of exergonic reaction. Exergonic reaction releases work energy in different forms like heat, light or sound. For example, a glow stick releases light making that an exergonic reaction and not an exothermic reaction since no heat is released. Even endothermic reactions at very high temperature are exergonic.
A 19.51 ݃ sample of impure methylamine, which contains 72.58% (by mass) of CH3NH2 , is
reacted with 30.81 ݃ of pure oxygen gas:
4CHଷNHଶ(g) + 9Oଶ(g) ⟶ 4COଶ(g) + 10HଶO(ℓ) + 2Nଶ(g) In another experiment, this impure methylamine was used as follows:
An unknown mass of the impure compound is dissolved in enough water to make 500.0 ݉ܮ
of solution.
20 ݉ܮ of this solution was transferred by pipette to a clean 250 mL volumetric flask and
made up to the mark.
The molarity of the CH3NH2 in the final solution was determined to be 0.103 M.
Determine the mass of CH3NH2 present in the original amount of impure compound used to
make this solution.
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