Identify which of the following changes is exothermic.
a) liquid water boils to steam
b) liquid water freezes to give ice
c) ice melts to give liquid water
d) liquid water increases in temperature from 35 C to 45 C
b.The liquid water freezes because heat is given off from it(exothermic) to form ice unlike other options.
heat comes out when you convert water to ice
For water to to boil,ice to melt and for temperature to increase from 35C to 45C,it means heat is absorbed(endothermic).
Yes, I agree with you Jonathan.
To identify which of the following changes is exothermic, we need to understand the concept of endothermic and exothermic reactions. An endothermic reaction is a process that absorbs heat from its surroundings, while an exothermic reaction is a process that releases heat into its surroundings.
Now, let's analyze each of the options:
a) Liquid water boils to steam: This is an endothermic reaction because heat is absorbed to break the hydrogen bonds between water molecules and convert liquid water into steam.
b) Liquid water freezes to give ice: This is an exothermic reaction because heat is released as the water molecules slow down and form a crystalline structure to become solid ice.
c) Ice melts to give liquid water: This is an endothermic reaction because heat is absorbed to break the hydrogen bonds within the ice lattice and convert the solid ice into liquid water.
d) Liquid water increases in temperature from 35°C to 45°C: This is an endothermic reaction because heat is absorbed as the water molecules gain kinetic energy and their temperature rises.
From the options provided, option b) "liquid water freezes to give ice" is the exothermic change since it involves the release of heat into its surroundings.