Answer:
Calcium sulfide (CaS)
Step-by-step explanation:
From the question
Number of mole (n) = reacting mass (R)/molar mass (m)
n = R/m.................... Equation 1
make m the subject of the equation
m = R/n...................... Equation 2
Given: R = 0.206, n = 0.00285 moles.
Substitute these values into equation 2
m = 0.206/(0.00285)
m = 72.3 g/mol
From the above, the compond with molar mass close to 72.3 g/mol is Calcium sulfide (CaS)