9.1

My solution process was endothermic. I know this because the temperature of the solution was 14.4 degrees higher than the original temperature of the water. When the element was added to the water the heat transferred from the surroundings of the water into the water.

One thing that could cause different values is measurement. If you used too much or too little of a substance then it could have caused our values to vary. Another way would be that they used pure water in their calculations but the tap water has iron in it.

3.)  
a)  If the temperature of the room was 10 degrees colder there would be less moles of solute because the colder it is the slower the reaction happens

b) If you added less chemical but knew how much you added the moles of solute would be greater because there's less chemical but the reaction happens fast because there's less chemical to dissolve

c) If you added 40 mL of water but thought you added 50 mL you would have less moles of solute because there's less water for the chemical to be dissolved in