Calculate the predicted density for calcium,Ca,given the density of strontium,Sr, (2.63g/cm3)and barium,Ba, (3.65 g/cm3).

Question

Quizplus · Accepted Answer

The atomic masses of the three elements (rounded to the nearest whole number) are:
Calcium, Ca: 40
Strontium, Sr: 87
Barium, Ba: 137

The predicted density of calcium, based on its position between strontium and barium in the periodic table, can be found using the equation:
(predicted density of Ca - density of Sr) / (density of Ba - density of Sr) = (atomic mass of Ca - atomic mass of Sr) / (atomic mass of Ba - atomic mass of Sr)

Plugging in the values:
(predicted density of Ca - 2.63) / (3.65 - 2.63) = (40-87)/(137-87)
(predicted density of Ca - 2.63) / 1.02 = -47/50
predicted density of Ca - 2.63 = -0.9696
predicted density of Ca = 1.6604 g/cm3

The closest answer choice is B) 1.61 g/cm3.

Calculate the Predicted Density for Calcium,Ca,given the Density of Strontium,Sr