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andre [41]
4 years ago
7

Review energy changes by identifying the correct statements about each reaction.

Chemistry
1 answer:
Grace [21]4 years ago
5 0

Answer: The reaction is exothermic

The \Delta H value is negative.

Heat is a product.

Explanation:

2H_2(g)+O_2(g)\rightarrow 2H_2O(l)+136.6kcal

Endothermic reactions are defined as the reactions in which energy of the product is greater than the energy of the reactants. The total energy is absorbed in the form of heat and \Delta H for the reaction comes out to be positive.

Exothermic reactions are defined as the reactions in which energy of the product is lesser than the energy of the reactants. The total energy is released in the form of heat and \Delta H for the reaction comes out to be negative.

The substances which are written on the left side of the arrow are reactants and the substances which are written on the right side of the arrow are products. Thus heat is a product.

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Acetylene gas (c2h2) reacts with oxygen gas (o2) to produce carbon dioxide (co2) and water vapor (h2o). how many liters of c2h2
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According to the balanced equation of the reaction:

2C2H2 + 5O2 → 4CO2 + 2H2O

So we can mention all as liters,

A) as we see that 2 liters of C2H2 react with 5 liters of oxygen to produce 4 liters of CO4 and 2 liters of H2O 

So, when we have 75L of CO2

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∴ The volume of C2H2 required is:

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B) and, when we have 75 L of CO2


and 4CO2 → 2H2O 

∴ the volume of H2O required is: 
                               
                            = 75 L /2
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C) and from the balanced equation and by  the same way:

when 5 liters O2  reacts to give 4 liters of CO2

and we have 75 L of CO2:

5 O2 → 4 CO2 

   ??  ←  75 L

∴ the volume of O2 required is:

                              = 75 *(5/4)

                              = 93.75 L



D) about the using of the number of moles the answer is: 

no, there is no need to find the number of moles as we called everything in the balanced equation by liters and use it as a liter unit to get the volume, without the need to get the number of moles.
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