Arsenic reacts with chlorine to form a chloride if 1.587 g of arsenic reacts with 3.755 g of chlorine what is the simplest formula of the chloride

Determining the number chloride molecules that will result from this reaction requires we first determine the number of moles of arsenic and the number of moles of chlorine on hand.

1.587 grams of arsenic divided by its atomic weight of 74.92 grams per mole results in 0.0212 moles.

We do the same for chlorine. 2.755 grams of chlorine divided by 35.45 grams per mole gives us 0.106 moles.
0.106 moles divided by .0212 moles equals 5; therefore, the simplest formula of the chloride produced will be AsCl₅.

the catch is that the top numbers are atomic masses the bottom numbers are the numbers of protons and electrons in an uncharged atom. they are the number of that atoms as you would find them on the periodic table. further, the numbers on the left are used to determine the missing numbers on the right

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer