What is the
empirical formula for a compound that is 36.1% Ca and 63.9% Cl?

CaCl

2

Explanation:

As with all these problems, we assume a  

100

⋅

g

of compound, and divide through by the ATOMIC masses of each component element:

Moles of calcium

=

36.1

⋅

g

40.08

⋅

g

⋅

mol

−

1

=

0.901

⋅

mol

.

Moles of chlorine

=

63.9

⋅

g

35.45

⋅

g

⋅

mol

−

1

=

1.802 mol

.

We divide each molar quantity through by the smallest molar quantity (that of calcium) to give an empirical formula of  

CaCl 2

.

For ionic materials, we do not speak of the molecular formula, and the empirical formula is the formula we quote for reference.

they emit helium gas that attaches to nearby planets.

they remove low-mass elements from the planets’ crust.

they cause nuclear fusion inside the inner core of planets.

they produce heavy elements such as iron and gold.

explanation:

the ratio of the conjugate base to the acid required to attain the desired ph.