Advertisements
Advertisements
Question
Give examples of exothermic reactions i.e. heat evolved in each of the following:
(a) reaction between a solid and a liquid
(b) reaction between two gases
Give two examples of exothermic reactions seen in everyday life.
Advertisements
Solution
(a) Reaction between a solid and a liquid:
CaO + H2O → Ca(OH)3 + Δ
(b) Reaction between two gases are:
\[\ce{N2 + 3H2 ⇌[Fe-450°][200 atoms.] 2NH3 + \triangle}\]
[finely divided iron (Fe) - catalyst]
Examples of exothermic reactions are:
- Rusting of iron – the reaction is slow and the heat evolved is very less, hence unnoticeable.
- Setting of cement – cement setting liberates heat, hence concrete structures are set slowly.
- Human Body – many chemical reactions in our body are exothermic & provide energy to survive.
APPEARS IN
RELATED QUESTIONS
State whether the following statement is true or false. In case a statement is false, write the corrected statement.
Formation of manure from leaves is a physical change.
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Reduction is a chemical reaction in which there is
- removal of hydrogen
- removal of oxygen
- addition of oxygen
- none of these
TRUE \ FALSE
Weak electrolytes dissociate partially in their aqueous or fused state.
TRUE \ FALSE
Positively charged electrode is called the anode. True or false ?
Fill in the blank:
The substances which undergo chemical change are called _______
Write true or false.
A chemical equation gives only qualitative information of a chemical reaction.
Show with the help of diagram of electronic configuration how the following compound is formed from the constituent atoms.
Sodium chloride
What do you understand by precipitation reaction? Explain with examples.
State the type of reactions for the following represent and balance the ones that are not balanced.
NaOH + HCl → NaCl + H2O
What do you observe when Cl2 is passed through potassium iodide (KI) solution.
Give a chemical test to distinguish between the following gases.
NH3 and SO2
Write your observation and a balanced equation in the case of the following substances being heated.
Zinc carbonate.
Give reason for the following:
Even though rusting is an exothermic reaction, the heat evolved when an iron nail rusts is unnoticeable.
Give balanced equation for the following conversion affected by heat alone on the substance:
Hydrated copper sulphate to sulphur dioxide
Give a balanced equation for a reaction involving the evolution of gas on the addition of dilute acid to sodium sulphite.
Differentiate between the following:
Neutralization reaction and a precipitation reaction.
Limestone contains ______ mainly.
Which of the following is not an “element + element → compound” type reaction?
Burning of paper is the best example of ______ change.
Is the conversion of milk into ice cream a chemical change?
