If a system performs 147 kJ of work while receiving 47 kJ of heat, what is change in its internal energy?
1 answer:
Answer:
-100 kJ
Explanation:
We can solve this problem by applying the first law of thermodynamics, which states that:
where:
is the change in internal energy of a system
Q is the heat absorbed/released by the system (it is positive if absorbed by the system, negative if released by the system)
W is the work done by the system (it is positive if done by the system, negative if done on the system)
For the system in this problem we have:
W = +147 kJ is the work done by the system
Q = +47 kJ is the heat absorbed by the system
So , its change in internal energy is:
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Answer:
(a)
Moles of ammonium chloride = 0.5 mole
Mass of ammonium chloride formed = 26.7455 g
(b)
Mole of = 0.125 mole
Mass = Moles * Molar mass = 0.125 * 76.139 g = 9.52 g
Mole of = 0.25 mole
Mass = Moles * Molar mass = 0.25 * 34.1 g = 8.525 g
Explanation:
(a)
For the first reaction:-
The mole ratio of the reactants = 1 : 1
0.5 moles of ammonia react with 0.5 moles of hydrochloric gas to give 0.5 moles of ammonium chloride
So, <u>Moles of ammonium chloride formed = 0.5 moles</u>
Molar mass of ammonium chloride = 53.491 g/mol
<u>Mass = Moles * Molar mass = 0.5 * 53.491 g = 26.7455 g</u>
(b)
For the first reaction:-
The mole ratio of the reactants = 1 : 4
It means
0.5 moles of methane react with 2.0 moles of sulfur to give 0.5 moles of Carbon disulfide and 1.0 moles of hydrogen sulfide gas.
But available moles of S = 0.5 moles
Limiting reagent is the one which is present in small amount. Thus, S is limiting reagent.
The formation of the product is governed by the limiting reagent. So,
4 moles of S produces 1 mole of
Thus,
0.5 moles of S produces mole of
<u>Mole of = 0.125 mole</u>
Molar mass of = 76.139 g/mol
<u>Mass = Moles * Molar mass = 0.125 * 76.139 g = 9.52 g</u>
4 moles of S produces 2 moles of
Thus,
0.5 moles of S produces mole of
<u>Mole of = 0.25 mole</u>
Molar mass of = 34.1 g/mol
<u>Mass = Moles * Molar mass = 0.25 * 34.1 g = 8.525 g</u>
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<u>Answer:</u> 4.999 moles of excess reactant will be left over.
<u>Explanation:</u>
Limiting reagent is defined as the reagent which is completely consumed in the reaction and limits the formation of the product.
Excess reagent is defined as the reagent which is left behind after the completion of the reaction.
The number of moles is defined as the ratio of the mass of a substance to its molar mass.
.....(1)
Given mass of aluminium carbide = 112 g
Molar mass of aluminium carbide = 143.96 g/mol
Putting values in equation 1:
For the given chemical reaction:
By the stoichiometry of the reaction:
2 moles of aluminium carbide reacts with 12 moles of water
So, 0.778 moles of aluminium carbide will react with = of water
Given mass of water = 174 g
Molar mass of water = 18 g/mol
Putting values in equation 1:
Moles of excess reactant (water) left = 9.667 - 4.668 = 4.999 moles
Hence, 4.999 moles of excess reactant will be left over.