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Multiple choice chemistry endothermic and exothermic reactions endothermic reactions what are enthalpy changes energy change in chemical reactions

Which of the following reaction is not endothermic in nature?

  1. breaking of bonds

  2. digestion of food

  3. combustion of Carbon

  4. evaporation of water
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Combustion or burning is a high temperature exothermic redox chemical reaction between fuel and an oxidant oxygen. Evaporation and sublimation are phase change physical process of water. Digestion of food is breakdown of larger molecules into small ones by bong breaking which is an endothermic process.

Multiple choice chemistry endothermic and exothermic reactions endothermic reactions what are enthalpy changes energy change in chemical reactions

Select the correct alternative.

Which of the following reactions are exothermic in nature?

  1. Combustion of Carbon

  2. Bond breaking

  3. Bond formation

  4. Both (a) and (c)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Combustion or burning is a high temperature exothermic redox chemical reaction between fuel and an oxidant oxygen. Bond breaking requires energy to be supplied for bond dissociation so it is an endothermic process while bond formation releases energy so that the product becomes stable which is an exothermic process.

Multiple choice chemistry endothermic and exothermic reactions endothermic reactions what are enthalpy changes energy change in chemical reactions

Which of the following is an exothermic process?

  1. Dilution of sulphuric acid

  2. Sublimation of dry ice

  3. Evaporation of water

  4. Melting of ice
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A large amount of heat is released because the hydration reaction of sulfuric acid is highly exothermic and dilution should always be performed by adding the acid to the water rather than the water to acid. As hydration of sulfuric acid is thermodynamically favorable and the affinity of it for water is sufficiently strong.

Multiple choice chemistry endothermic and exothermic reactions endothermic reactions what are enthalpy changes energy change in chemical reactions

If you pour a few drops of petrol on your palm, it will feel cool as the petrol evaporates. This change a/an:

  1. endothermic reaction

  2. exothermic reaction

  3. chemical reaction

  4. slow reaction
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

If you pour a few drops of petrol on your palm.it will feel cool as the petrol evaporates this is a endothermic reaction.Because petrol is very volatile in nature, so when it evaporates.it absorb heat energy from the surroundings.

Multiple choice chemistry endothermic and exothermic reactions endothermic reactions what are enthalpy changes energy change in chemical reactions

A chemical reaction in which energy is liberated is called:

  1. exothermic reaction

  2. endothermic reaction

  3. isothermal reaction

  4. physical change
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Exothermic Reaction: This is a chemical reaction that releases energy through light or heat.

$CH _4+2O _2\rightarrow CO _2+2H _2O+\triangle$
Burning of $CH _4$ gas its produces $CO _2$ and water vapour and releases heat.
Endothermic Reaction: This is a chemical reaction which requires or absorbs energy from its surroundings usually in the form of heat.
$N _2+O _2\rightarrow 2NO$
$\triangle0=+180.5$kg

Multiple choice chemistry endothermic and exothermic reactions endothermic reactions what are enthalpy changes energy change in chemical reactions

During the dissolution of urea, heat:

  1. is absorbed

  2. is evolved

  3. does not change

  4. none of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

During the dissolution of urea, heat is absorbed the term,dissolution,refers to a solute dissolving in a solvent to form a solution.In this experiment the solute is  solid urea.Urea being a molecular substance,does not dissociate into ions.The dissolution process involves adding energy to break the attractive forces between the molecules in the solid structure and releasing energy as the molecules form new attractive forces with the water molecules sourrounding it.

Multiple choice chemistry endothermic and exothermic reactions endothermic reactions what are enthalpy changes energy change in chemical reactions

One of the following is an exothermic reaction. This is:

  1. electrolysis of water.

  2. conversion of limestone into quicklime.

  3. process of respiration.

  4. process of photosynthesis.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

(A)In electrolysis of water heat energy is used to convert water into hydrogen and oxygen.

$2H _2O\rightarrow2H _2+O _2$
 it is an endothermic reaction.

(B)conversion of limestone into quicklime can be done by heating limestone.
$CaCO _3\rightarrow CaO+CO _2$ it is an endothermic reaction.


(C)During respiration breakdown of glucose in presence of oxygen releases energy, therefore it is an exothermic process.
$C _6H _{12}O _6+6O _2\rightarrow6H _2O+6CO _2+energy$

(D)In process of photosynthesis- light energy is used to convert carbon dioxide and water into glucose and oxygen
$6CO _2+6H _2O\rightarrow C _6H _{12}O _6+6O _2$

So the answer is (c)






.

Multiple choice chemistry endothermic and exothermic reactions endothermic reactions what are enthalpy changes energy change in chemical reactions

One of the following is an endothermic reaction. This is:

  1. combination of carbon and oxygen to form carbon monoxide.

  2. combination of nitrogen and oxygen to form nitrogen monoxide

  3. combination of glucose and oxygen to form carbon dioxide and water

  4. combination of zinc and hydrochloric acid to form zinc chloride and hydrogen.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
(A) This is an incomplete combustion reaction so energy will be released.
(B)Combination of nitrogen and oxygen to form Nitrogen Monoxide-
Heat is required for this process.
So $N _2 + O _2\rightarrow2NO-180.6KJ$ is an endothermic reaction.
(C) combination of glucose and oxygen to form carbon dioxide and water is a combustion reaction.So energy will be released.
(D)in a combination of zinc and hydrochloric acid to form zinc chloride and hydrogen heat is released.

so correct answer is  (B).
Multiple choice chemistry endothermic and exothermic reactions endothermic reactions what are enthalpy changes energy change in chemical reactions

The formation of a larger chemical from the smaller components is known as 

  1. an endothermic reaction that requires energy

  2. an endothermic reaction that releases energy

  3. an exothermic reaction that requires energy

  4. an exothermic reaction that releases energy

  5. hydrolysis
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The internal energy of a larger chemical is smaller than that of the constituent ones. Hence energy is liberated when smaller components combine to form a large molecule. Hence the process is exothermic.

The correct answer is option D.

Multiple choice chemistry endothermic and exothermic reactions endothermic reactions what are enthalpy changes energy change in chemical reactions

Which is a reaction that absorbs energy?

  1. Exothermic

  2. Particle Size

  3. Endothermic

  4. Catalyst

  5. Concentration
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The term endothermic process describes the process or reaction in which the system absorbs energy from its surroundings; usually, in the form of heat. The opposite of an endothermic process is an exothermic process, one that releases, "gives out" energy in the form of heat.