Massing The Moles Of Chocolate

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Massing the Moles of Chocolate Lab

During the holiday time, chocolate is a favorite treat of children (young and old). Chocolate is not a single substance but accurately a mixture where the main ingredient is cocoa. They believe cocoa is made up of thembroma oil, which they believe the chemical formula of this oil is C64H128O2. So I want you to mass out some chocolate.
How much you mass out depends on the number of moles of "chocolate" you are investigating. All groups will be assuming chocolate = all thembroma oil. So you will use the oil's chemical formula to determine the molar mass of the chocolate and thereby the mass you need to "weigh out" to obtain your group's desired moles.

Group 1 - 0.0100 moles    Group 6 - 0.0130 moles    Group 11 - 0.0143 moles

Group 2 - 0.0115 moles    Group 7 - 0.0133 moles    Group 12 - 0.0145 moles

Group 3 - 0.0120 moles    Group 8 - 0.0135 moles    Group 13 - 0.0147 moles

Group 4 - 0.0125 moles    Group 9 - 0.0137 moles    Group 14 - 0.0150 moles

Group 5 - 0.0127 moles    Group 10 - 0.0140 moles    Group 15 - 0.0153 moles


1) Using the space on the next page (or on a separate sheet of paper with info written on it), determine the mass you need for your Group's desire moles.

2) After checking your answer with the teacher, obtain a Zip lock bag.

3)Place Zip lock bag on scale and "zero" it out. Then add in calculated mass of chocolate into your bag (please make sure you are wearing gloves).

4) Bring bag with chocolate in it up to teacher's desk.
5) After teacher checks your mass, you can eat chocolate (or give it away).

Massing the Moles of Chocolate Lab

Name of Student:


Group # : ______     Desire Moles __________moles     Calculated mass _______g

Molar Mass of "Chocolate (remember g/mole): ______________________

Show work (as stated in notes and class below. Must be handwritten)


1. If you forgot to "zero out" the balance after you put the plastic bag on the scale and then weighed out "your calculated mass of chocolate". Would you have MORE, LESS or SAME moles of chocolate than you should have? Give a brief explanation of why?

Chocolate is not all thermobroma oil. So if it was known that the molar mass of chocolate was actually greater than the molar mass of thermobroma oil and you recalculated the mass of chocolate to get the same moles, would you mass be GREATER, SMALLER or the SAME ? Give a brief explanation of why?

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Last edited December 3, 2020 8:05 pm (diff)