The following set of procedures was used by a student to determine the heat of solution of NaOH
A) Read the original temperature of the water
B) Read the final temperature of the water
C) Pour the water into a beaker
D) Stir the mixture
E) Add the sodium hydroxide
What is the correct order of procedures for making this determination?
A. A-> C-> E-> B-> D
B. E-> D-> C-> A-> B
C. C-> A-> E-> D-> B
D. C-> E-> D-> A-> B
E. D-> C-> A-> B -> E
First pour water into a beaker and take the temperature of the water. Heat of solution will be measured by determining the change of temperature after the solute (NaOH) is added to the water (and stirred). Choices 2 and 4 do not make sense as the solute NaOH is added before the temperature of the water is taken: no change of temperature can be measured this way. Choice 1 takes the temperature of the water before it is added to the beaker. Where does the water come from? Then the final temperature is taken before the solution is stirred. This method gives inaccurate readings as the thermometer could be reading a "hot" or "cold" spot in the unstirred liquid.