The chemical reaction 2Cu + O2 → 2CuO + 315 kJ is an _____ reaction. Endothermic, combustion Exothermic, combustion Endothermic,
2 answers:
Answer: Exothermic
Explanation: Combustion reaction is a chemical reaction in which hydrocarbon burns in the presence of oxygen to form carbon dioxide, water and energy.
Exothermic reactions are those in which energy is released and endothermic reactions are those in which energy is absorbed.
A single replacement reaction is one in which a more reactive element displaces a less reactive element from its salt solution.
As in the given reaction, the energy is released thus reaction s exothermic.
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The new volume : 0.07 L
<h3>Further explanation</h3>Boyle's Law
At a constant temperature, the gas volume is inversely proportional to the pressure applied
P₁=1 atm
V₁=0.39 L
P₂=5.6 atm
There are:
3.41 moles of C
4.54 moles of H
3.40 moles of O.
Why?
To solve the problem, the first thing that we need to do is to write the chemical formula of the ascorbic acid.
Now, we know that there are 100 grams of the compound, so, the masses of each element will represent the percent in the compound.
We have that:
To know the percent of each element, we need to to the following:
So, we know that for the 100 grams of the compound, there are:
40.92 grams of C
4.58 grams of H
54.49 grams of O
We know the molecular masses of each element:
Now, to calculate the number of moles of each element, we need to divide the mass of each element by the molecular mass of each element:
Hence, we have that there are 3.41 moles of C, 4.54 moles of H, and 3.40 moles of O.
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