Passage I
When a substance dissolves in H2O, heat is either absorbed from or given off to the solution. “Experiments were done in which a known mass of a solute was added to a known mass of H2O at a known initial temperature (Ti) in a closed, insulated container. When the maximum 'temperature change of the solution had occurred, the final temperature (Tf) was recorded. The maximum temperature change (△T) was then calculated as follows:
△T = Tf - Ti
Figures 1 and 2 show the results for lithium chloride (LiCl) and ammonium nitrate (NH4NO3), respectively. In each trial, all of the solute completely dissolved.
1. Based on Figure 1, when 5 g of LiCl was added to 50 g of H2O, the temperature:
Your Answer is
Correct Answer is D
Explanation
Observing figure 1, it can be seen that after adding 5g LiCI to 50g H2O, the temperature of the mixture is higher than that of the original liquid, so the temperature rises and heat is added