The magic salt
Question:

 An experiment was conducted with two cups containing 100 ml of water each, cup A had only water and we added 10 grams of calcium chloride (CaCl2 ( to the cup B.

Temperature was measured in each of the cups in the beginning of the experiment and after five minutes. The following are the results of the experiment:

Temperatures in the cups during the experiment

Temperature after 5 minutes

 ((C°

Temperature at the beginning  

 ((C°

Mass of calcium chloride (grams)

 

18

18

0

cup A

27

18

10

cup B

What can be concluded from these results?
Use the 
video and the simulation below for more information, Then choose the correct answer.

(In addition, Calcium chloride (CaCl2) is an Ionic substance that can be used in order to melt snow. For more information go to the map.)




      Exothermic        Endothermic    
         reaction              reaction








1 People tried to answer this question

All the substances dissolves in water.

The reaction of dissolving calcium chloride in the water is an exothermicreaction.

The reaction of dissolving calcium chloride in water isan endothermic reaction.

All the water-soluble substances radiate heat.



Comments:
1.  amer athar (2013-12-20 15:00:00)
magic salt - comment

Hi fareda,

First of all , I liked your idea, I think it appropriate to the mission .

References to improve :

 1. I think the video should be on the point in the map and not in the question, in the question you could put only the simulation.

2.The distracting should be more difficult, for example in orde to say " The reaction of dissolving calcium chloride in water is an endothermic reaction"

you should say for example , in this reaction , the energy of the reacts bigger than the energy of the products.

will done , nice work


2.  Guetta Julia (2014-12-20 15:00:00)
משוב
אני חושבת שהשאלה מאד מוצלחת אחרי התיקונים שעשית, לדעתי התגובה שהגבתי מקודם נמחקה!!!!
יוליה
3.  kablan farida (2014-12-20 15:00:00)
תגובה
כן גוליה
זה עזר לי מאוד תודה רבה על ההערות
גם אני לא מצליחה לראותה..חשבתי שאת מחקת אותה..מעניין
נראה לי שעדיף שתרשמי אותה שוב ליתר בטחון
והמרצה בקשה שתהיה כתובה בשפה האנגלית.. זו הזדמנות גם לכתוב אותה עכשיו כפי שהתבקשנו ;)
פרידה
4.  Guetta Julia (2014-12-20 15:00:00)
Responce
Hei!

First, I liked very much the map point, this story added information to better understanding of your quiestion! The exepriment, that You did also was very good demonstration of the exothermic reactions.
To improve: The main question is missing. And I think, that the youtube film is confusing.
Good luck!
Julia


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