1. 0.224 M is the molarity of the solution made with 25.2 grams CaO in 2 litres of solution.
2. 0.48 M is the molarity of the solution formed when 0.72 moles of CaBr2 is dissolved in 1.50 L water.
3. 262.84 gm/mole is the molar mass of Mg3(PO4)2.
Step-by-step explanation:
1. Data given:
weight of the mass of CaO = 25.2 grams
Atomic weight of one mole of CaO = 56.07 gram/mole
number of moles = mass÷atomic mass of one mole of the substance
= 25.2 ÷ 56.07
= 0.449 moles of CaO is used to make a solution of 2 Litres
formula for molarity:
molarity = number of moles ÷ volume in litres
= 0.449 ÷ 2
= 0.224 M
2. Data given:
number of moles of CaBr2 = 0.72 moles
volume of the water used = 1.50 L
Formula of molarity:
molarity = number of moles ÷ volume in litres
molarity = 0.72 ÷ 1.5
= 0.48 M
3. Molar mass of a compound is calculated by adding the number of moles of elements taking part in the formation of the compound.
Mg = 24.30 gm/mole
P = 30.97 gm/mole
O = 16 gm/mole
3 moles of Mg ( 24.3 x 3) + 2 moles of P (2 x 30.97) + 8 moles of O (8 x 16)
= 262.84 gm/mole is the atomic weight of Mg3(PO4)2