Question #c894f

1 Answer
Stefan V.
Oct 13, 2015

Here's what you need to do.

Explanation:

To get the formula mass of sodium chloride, #"NaCl"#, you need to add the molar masses of its constituent atoms, sodium and chlorine.

The atomic masses of sodium and of chlorine are

#"Na: " "22.990 u"#

#"Cl: " "35.453 u"#

Since a formula unit of sodium chloride cotnains *one* sodium atom and one** chlorine atom, the formula mass of sodium chloride will be

#1 xx "22.990 u" + 1 xx "35.453 u" = "58.443 u"#

To get the percent composition of the compound, use the atomic masses of each constituent atom and the formula mass

#"For Na: " (22.990color(red)(cancel(color(black)("u"))))/(58.443color(red)(cancel(color(black)("u")))) xx 100 = "39.34% Na"#

#"For Cl: "(35.453color(red)(cancel(color(black)("u"))))/(58.443color(red)(cancel(color(black)("u")))) xx 100 = "60.66% Cl"#

So, according to the percent composition of sodium chloride, every #"100 g"# of sodium chloride will contain #"39.34%# sodium and #60.66%# chlorine.

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