[ARGOS++]

[mr cool]

Here is a new problem that i just tried..

Melting ice in your mouth requires a lot of heat energy, this is why it cools you down. How many calories will your body burn if you melt 6.0 grams of -25.0^oC ice in your mouth to body temperature of 37.0^oC?

Here is my stab at it....

(1.0 cal/g)(6.0g)(37^oC - 0^oC) = 2220 cal.
(80 cal/g)(6.0g) = 480
(.5 cal/g)(6.0g)(0^oC - ^-25^oC) = 75 cal
Total = 2775 calories needed

The wording of this problem threw me off a bit so i didn't know if it was an exothermic or endothermic process.  i think "this is why it cools you down" gives it away though, yes?  I think i did it as exothermic.

[ARGOS++]

Dear reezyfbaby;

How much is 1 * 6 * 37?

And think also about that you have to spend the heat, so the process is consuming heat.

Good Luck!
                    ARGOS⁺⁺

[mr cool]

oh my bad,  you are right it should be 222 not 2220, i must have hit some bad keys on my calculator.

was the problem correct though?

and isn't it exothermic because the ice is taking energy (heat) from the mouth?

[ARGOS++]

[mr cool]

Alright i think this is the last problem i have....


A serving of Doritos contains 160.0 Kilo calories (big C's). Your mouth is at body temperature 38.0^oC.  What mass of -25.00^oC ice do you have to eat to burn all the calories in one serving of Doritos.


Do i have to convert the 160.0 Kilo calories into regular calories.  160.0 Kilo calories is 160000 calories.

so far i have..

160000 calories = (.5 cal/g)(25.0^oC)(M)+(80 cal/g)(M)

for this problem i used M as a place holder for mass.

[ARGOS++]

[mr cool]

here is my second try...

160000 calories = (.5 cal/g)(25.0oC)(M)+(80 cal/g)(M) + (1.0 cal/g)(M)(38.0^oC - 0^oC) = 103.5 g of ice required?

[ARGOS++]

Dear reezyfbaby;

The values in the equation are correct, but I get more than 1.035 kg Ice.
Please calculate once more.

Good Luck!
                    ARGOS⁺⁺

[mr cool]

Dear reezyfbaby;

The values in the equation are correct, but I get more than 1.035 kg Ice.
Please calculate once more.

Good Luck!
                    ARGOS⁺⁺

i got 103.5 not 1.035

[ARGOS++]

[mr cool]

Yea i got 130.5 too. I wrote the wrong number off the calculator lol.  I wound up with 1.22 g of ice needed.

[ARGOS++]

[mr cool]

Do the sig figs come out to 3 or 4?

[ARGOS++]

Dear reezyfbaby;

Of course NOT!, because the limited precision.
But you wrote:  gram ice instead of kg ice.

Good Luck!
                    ARGOS⁺⁺