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Question:

AP Chemistry Weight Percent Problem?

Sorry the subscripts in the equations wouldnt work!Calcium and magnesium carbonates occur together in the mineral dolomite. Suppose you heat a sample of the mineral to obtain the oxides CaO and MgO and then treat the oxide sample with HCl. If 7.695g of the oxide sample requires 125mL of 2.44M HCl, CaO (s) + 2HCl(aq) -----gt; CaCl2(aq) + H2O (l)MgO(s) + 2HCl(aq) -----gt; MgCl2 (aq) + H2O (l)What is the weight percent of each oxide (CaO and MgO) in the sample?

Answer:

as Corky stated all the answers in fact are good flag or color both ends of the white wire to help stop the confusion in the future after verifying it is a hot connected to the breaker .
Local codes can supersede the NEC so to be certain of what the local or state codes require you need to contact the local AHJ and ask them. In general it should meet code but the local AHJ may be more stringent.
effectively you have an algebraic problem, say you have xg of one oxide and yg of the other. The sum of x and y 7.695 Dividing each by their formula weight to get the number of mole each and adding the total number of mole (xCaO/FW +yMgO/FW) the number of mole HCl ((125*2.44)/100). Two unknowns, two equations, take it from there.

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