Which of the following chemical reactions is an example of an endothermic reaction?
A. Making ice cubes from liquid water
B. Burning a candle
C. The evaporation of water
D. The combustion of gasoline
I think c
right.
liquid water + heat ==> steam adds heat so it is endothermic.
Note that many thing freezing water to ice is endothermic too but it is exothermic and one equation like the one above will show it.
ice cubes + heat ==> liquid water is an endothermic process because heat must be added to melt ice. Now just reverse the arrow.
ice cubes + heat <== liquid water and now turn it around to make
liquid water ==> ice + heat and that clearly shows making ice cubes is an exothermic process.
The correct answer is:
C. The evaporation of water.
In an endothermic reaction, energy is absorbed from the surroundings, resulting in a decrease in temperature. The process of water evaporation requires energy to break the hydrogen bonds between water molecules, which leads to a decrease in temperature.
To determine which of the given chemical reactions is an example of an endothermic reaction, we need to understand what an endothermic reaction is.
An endothermic reaction is a chemical reaction that absorbs heat energy from its surroundings. This means that the reaction requires an input of external energy to occur, resulting in a decrease in the temperature of the surroundings.
Now, let's examine each option:
A. Making ice cubes from liquid water: This process involves the phase change from liquid to solid, which is an exothermic process since it releases heat energy. So, A is not an example of an endothermic reaction.
B. Burning a candle: The combustion of a candle involves the reaction between the wax and oxygen, which is highly exothermic. It releases heat and light energy as a result, making B not an example of an endothermic reaction.
C. The evaporation of water: The process of evaporation involves the conversion of liquid water into water vapor, which requires heat energy input. This heat energy is absorbed from the surroundings, making C an example of an endothermic reaction.
D. The combustion of gasoline: Similar to burning a candle, the combustion of gasoline is a highly exothermic reaction. It releases a large amount of heat energy when gasoline reacts with oxygen, making D not an example of an endothermic reaction.
Therefore, the correct answer is C. The evaporation of water is an example of an endothermic reaction.