Tag: energy change in chemical reactions

Questions Related to energy change in chemical reactions

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

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

  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.

Show answer
Correct Option: B
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).

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

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

  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

Show answer
Correct Option: C
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.

Which is a reaction that absorbs energy?

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

  1. Exothermic

  2. Particle Size

  3. Endothermic

  4. Catalyst

  5. Concentration

Show answer
Correct Option: C
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.

Which term means a reaction which releases energy?

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

  1. Exothermic

  2. Particle Size

  3. Endothermic

  4. Catalyst

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Correct Option: A
Explanation:

An exothermic reaction is a chemical reaction that releases energy by light or heat. It is the opposite of an endothermic reaction. Expressed in a chemical equation: reactants → products + energy.

The dissolution in water of which of the following substances is endothermic?

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

  1. Hydrochloric acid

  2. Sodium hydroxide

  3. Pure sodium

  4. Ammonium chloride

Show answer
Correct Option: D
Explanation:

(A) $HCl _{(l)}+H _2O _{(l)}\rightarrow HCl _{(aq)}+$ Heat (exothermic)

(B) $NaOH+H _2O\rightarrow Na^++OH^-+H _2O+$ Heat (exo)
(C) $Na _{(s)}+H _2O\rightarrow NaOH+$ Heat (exo)
(D) $AlCl _3+H _2O\rightarrow Al(OH) _3+3HCl$ (endo)

(D) is endothermic reaction.

The decomposition of vegetable into compost is an example of __________ reaction.

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

  1. exothermic

  2. endothermic

  3. displacement

  4. none of these

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Correct Option: A
Explanation:

The decomposition of vegetable into compost is an example of  exothermic reaction.

The decomposition of vegetable matter into useful compost is carried out by microbes.These reactions involve break down of bonds.The overall reaction is exothermic.

$Si + C \rightarrow$ SiC. This chemical reaction is an example for:

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

  1. exothermic reaction

  2. endothermic reaction

  3. dissociation reaction

  4. displacement reaction

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Correct Option: A
Explanation:

$Si + C \rightarrow SiC$.

This chemical reaction is an example of an exothermic reaction as heat is liberated during the reaction. It is also an example of a combination reaction. Two elements combine to form a single compound.

To start, every biochemical reaction is:

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

  1. exergonic

  2. endergonic

  3. both $A$ and $B$

  4. none of the above.

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Correct Option: B
Explanation:

Since any chemical reaction requires some energy of activation to start with, so this step is endergonic or since biochemical reaction is also a type of chemical reaction, so its first step is endothermic or endergonic.

A solution of 500 ml of 0.2 M KOH and 500 ml of 0.2 M HCl is mixed and stirred; the rise in temperature is $T _1$. The experiment is repeated using 250 ml of each solution, the temperature raised is $T _2$. Which of the following is true :

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

  1. $T _1=T _2$

  2. $T _1=2T _2$

  3. $T _1=4T _2$

  4. $T _2=9 T _1$

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Correct Option: A

The following is (are) endothermic reaction(s) :

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

  1. Combustion of methane.

  2. Decomposition of water

  3. Dehydrogenation of ethane to ethylene.

  4. Conversion of graphite to diamond.

Show answer
Correct Option: B,C,D
Explanation:

Combustion reaction are exothermic, hydrogenation of alkenes are exothermic and graphite is thermodynamically more stable.