ChemMasters,
What with the weather getting colder here in Chicago and Madonna Enterprises reeling from the devastating blow we delivered to their drugstore product line, not to mention their alcohol business, it's time to think about a new product - hand warmers!
Have your fingers ever been so cold they felt numb? Wouldn't it be great if you could generate heat to warm your hands up anytime you want to? That's exactly what a "hand warmer" does. Hand warmers are small packets that people put inside gloves or mittens on cold days to keep their fingers warm. They are very popular with people who work outside in winter or engage in winter sports. One type of hand warmer contains water in one section of the packet and a soluble substance in another section. When the packet is squeezed, the water and the soluble substance are mixed, the solid dissolves, and the packet becomes warm.
Your tasks involve the following:
1. Make a CLAIM as to how much of which salt you would use to make a hand warmer that will heat up 50.0mL of water exactly 20.0⁰C.
2. Provide DATA to support your claim, as well as data comparing your salt to other possible salt options. Your data should include a discussion of R2, accuracy and precision of your data. This means that you will need to conduct multiple trials and create a line of best fit.
3. Our legal department cares very much that the hand warmer is safe, should it break open on a consumer. Finally, our investors care very much about the cost of the hand warmer. Provide them with data as to how much each hand warmer would cost to produce. These 2 factors need to be included in your evidence to support your claim.
4. The investors also happen to care about your understanding of the energetics involved in the process of dissolution. You need to include reasoning relating to the chemistry of dissolving including how bond breaking and bond forming plays a role in your hand warmer.
To accomplish tasks…
Collect data on several different soluble substances relating to their ability to release heat. Your investors will want to know accurate (yes, accurate) and precise ∆H values for the salt that you choose. You will be graded on your ability to present your pertinent data to an educated customer who is interested in the research behind your hand-warmer design.
I look forward to reading your design proposals! (Only information contained in this handout needs to be included in your final report.)
Sincerely,
Mr. BrINClHOF
Mr. BrINClHOF