Answer:
Explanation:
A. molecules of CaCO3 = number of moles x avogadros number
= 2.5 x 6.022 x 10^-23 = 1.5055 x 10^-22
B. the mass of 2 moles of Al2O3 is = molar mass of Al2O3 x number of moles
the molar mass of Al2O3 = 2 x molar mass of Al + 3 x molar mass of O
= 2 x 27 + 3 x 16 = 102 g/mol
the mass of Al2O3 = 102 x 2 = 204 g
C. 1 mol of Be3N2 = number of moles x molar mass of Be3N2
molar mass of Be3N2 = 3 x molar mass of Be + 2 x molar mass of N
= 3 x 9 + 2 x 14 = 55g/ mol
so the mass of 1 mol of Be3N2 is 55 g