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    Number of moles

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    Question 1

    a)

    The molecular weight of $\mathrm{CaCl_2.2H_2O}$ is  g/mol (round each atomic weight to the nearest whole number for this exercise).

    The atomic mass of Ca is 40, the atomic mass of Cl is 35, the atomic mass of H is 1 and the atomic mass of O is 16. Therefore, the molecular mass of $\mathrm{CaCl_2.2H_2O}$ is $40+2\times 35 +2\times(2\times 1+16)=146$.

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            b)

            How many moles of $\mathrm{CaCl_2.2H_2O}$ are present in 292 g of $\mathrm{CaCl_2.2H_2O}$?

             moles

            The number of moles is the weight of the compound in grams/mol divided by the molecular mass of the compound in grams.

            In particular, the number of moles in 292 g of $\mathrm{CaCl_2.2H_2O}$ is calculated as follows:

            $\dfrac{\text{mass of compound (g)}}{\text{molecular mass (g/mol)}}$ $=$ $\dfrac{\var{grams} \text{g}}{\var{chem[2]} \text{g/mol}}$
            $=$ $\var{mult}$ mol
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