Question

Give two example of heat,electricity,sunlight of endothermic reaction 0

Answer 1

endothermic reaction involving:-
•HEAT
C +2S +HEAT ------》CS2
CACO3 + HEAT -----》CaO + CO2
•ELECTRICITY
KCI + ELECTRIC CURRENT --》K +Cl
2H2O + ELECTRICITY ---》2H2 + O2
•SUNLIGHT
2AgNO3 + sunlight ---》2Ag + 2NO2 + O2
6CO2 + 12H2O + chlorophyll + sunlight --》C6H12O6 + 2NO2 + O2

** hope this answer helps **

Answer 2

calcium carbonate (limestone) ==> calcium oxide (lime) + carbon dioxide

CaCO3 (+ heat energy) ==> CaO + CO2

This only happens at temperatures above 900oC.

the cracking of oil fractions (see Oil products)

e.g. octane (+ heat energy) ==> hexane + ethene

C8H18 ==> C6H14 + C2H4

Again this needs a very high temperature AND a catalyst too.

Electricity -

H20 + Electricity - - - - > H2+O2


The energy from sunlight is absorbed as water and carbon dioxide are converted to glucose and oxygen.

6H2O + 6CO2 + sunlight energy ==>C6H12O6 + 6O2

However, on 'burning' the glucose/carbohydrates in our bodies, the 'stored' sunlight energy is released to keep us warm and drive all the chemical processes in our cells, so the opposite reaction is exothermic!

C6H12O6 + 6O2  ==>  6H2O(l) + 6CO2  + heat/chemical energy