When you crush a first-aid pack for an injured athlete and the pack gets cold, which of the following is true?
2 answers:
Answer: Option (d) is the correct answer.
Explanation:
A chemical reaction in which heat is released by the reactants is known as an exothermic reaction.
For example,
As energy is released, hence total energy of products is less than the total energy of reactants in an exothermic reaction.
On the other hand, a chemical reaction in which heat is absorbed by reactant molecules is known as an endothermic reaction.
For example,
As energy is absorbed, hence total energy of reactants is less than the total energy of products in an endothermic reaction.
Thus, we can conclude that when you crush a first-aid pack for an injured athlete and the pack gets cold, a chemical change has occurred, with energy being absorbed.
You might be interested in
Answer: 1123000 Joules of energy are required to vaporize 13.1 kg of lead at its normal boiling point
Explanation:
Latent heat of vaporization is the amount of heat required to convert 1 mole of liquid to gas at atmospheric pressure.
Amount of heat required to vaporize 1 mole of lead = 177.7 kJ
Molar mass of lead = 207.2 g
Mass of lead given = 1.31 kg = 1310 g (1kg=1000g)
Heat required to vaporize 207.2 of lead = 177.7 kJ
Thus Heat required to vaporize 1310 g of lead =
Thus 1123000 Joules of energy are required to vaporize 13.1 kg of lead at its normal boiling point