When calcium carbide is placed in a beaker of water, the reaction produces an unknown hydrocarbon gas, CxHy. To determine the identity of the hydrocarbon gas produced, a student fills a beaker with water, zeros the scale, and adds a piece of calcium carbide to the water. After the gas escapes, she writes down the following: (a) If the hydrocarbon is 92.2% C and 7.8% H, determine the empirical formula. (b) Using the data from the table, determine the molar mass of the gas. (c) Suppose that the hydrocarbon has a molar mass of 78.10 g/mol. Based on your empirical formula from (a), determine the molecular formula.
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.
When calcium carbide is placed in a beaker of water, the reaction produces an unknown hydrocarbon gas, CxHy.
To determine the identity of the hydrocarbon gas produced, a student fills a beaker with water, zeros the scale, and adds a piece of calcium carbide to the water. After the gas escapes, she writes down the following:
(a) If the hydrocarbon is 92.2% C and 7.8% H, determine the empirical formula.
(b) Using the data from the table, determine the molar mass of the gas.
(c) Suppose that the hydrocarbon has a molar mass of 78.10 g/mol. Based on your empirical formula from (a), determine the molecular formula.
Step by step
Solved in 4 steps
