Question

what is the formula of the compound between calcium and sulfur that has the percent composition 55.6% calcium and 44.4% sulfur

Answer 1

Answer: The empirical formula is
`CaS`.

Step-by-step explanation:

If percentage are given then we are taking total mass is 100 grams.

So, the mass of each element is equal to the percentage given.

Mass of Ca = 55.6 g

Mass of S= 44.4 g

Step 1 : convert given masses into moles.

Moles of Ca=
`\frac{\text{ given mass of Ca}}{\text{ molar mass of Ca}}= (55.6g)/(40g/mole)=1.39moles`

Moles of S = \frac{\text{ given mass of S}}{\text{ molar mass of S}}= \frac{44.4g}{32g/mole}=1.39moles[/tex]

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For Ca =
`(1.39)/(1.39)=1`

For S =
`(1.39)/(1.39)=1`

The ratio of Ca:S = 1:1

Hence the empirical formula is
`CaS`.

Answer 2

We are given with two elements and their respective percent composition. Having a 100 grams basis, we convert each mass to moles. Calcium is equivalent to 1.39 moles and sulfur equal to 1.3849 moles. We divide each from the smaller number between the two. Hence, Ca is 1 and S is also 1. The compound formula is CaS or calcium sulfide.