Use average atomic masses to calculate the number of moles of the element present in each...

Use average atomic masses to calculate the number of moles of the element present in each of the following samples.

(a) 66.76 g of fluorine atoms

(b) 405.0 mg of mercury

(c) 84.04 g of silicon

(d) 48.65 g of platinum

(e) 2426 g of magnesium

(f) 47.77 g of molybdenum

Expert Solution

(a) 66.76 g of fluorine atoms
mass= 66.76 gm
molar mass of F = 19 gm
number of moles of fluorine atoms = mass /molar mass
                                                                               = 66.76/19
                                                                                 = 3.5 mol
(b) 405.0 mg of mercury
mass= 405 mg = 0.405 gm
molar mass of mercury = 200.5 gm
number of moles of mercury = mass /molar mass
                                                                               = 0.405/200.5
                                                                                 = 2.02*10^-3 mol
                                                                                 = 2.02 mmol
(c) 84.04 g of silicon
mass= 84.04 g
molar mass of silicon= 28 gm
number of moles of silicon= mass /molar mass
                                                                               = 84.04/28
                                                                                 = 3 mol
(d) 48.65 g of platinum
mass= 48.65 g
molar mass of platinum= 195 gm
number of moles of platinum= mass /molar mass
                                                                               = 48.65 /195
                                                                                 = 0.25 mol
(e) 2426 g of magnesium
mass= 2426 g
molar mass of magnesium= 24 gm
number of moles of magnesium= mass /molar mass
                                                                               = 2426 /24
                                                                                 = 101.1 mol
(f) 47.77 g of molybdenum
mass= 47.77 g
molar mass of molybdenum= 96 gm
number of moles of molybdenum= mass /molar mass
                                                                               = 47.77 /96
                                                                                 = 0.5 mol

queen_honey_blossom answered 1 year ago

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