How many moles and numbers of ions of each type are present in the following aqueous solutions?

(a) 2.1 mL of 1.75 M magnesium chloride





(b) 434 mL of a solution containing 3.94 g/L aluminum sulfate





(c) 3.41 L of a solution containing 6.74 1021 formula units of lithium nitrate per literHow many moles and numbers of ions of each type are present in the following aqueous solutions?
concentration * volume = mass, right?


1 mole = Avogadro's number of molecules = 6.023e23 molecules


for inorganic salts, all of them ionize in solution:





a) MgCl2 --%26gt; Mg[2+] + 2 Cl[1-] one 2+ ion, two 1- ions


(2.1 ml)*(1.75 mol/L)*(1 L / 1000 ml) = 0.003675 mol


2+ ion: 3.7e-3 mol; 3.7e-3 * 6.023e23 = 2.2e21 ions


1- ion: 2*3.7e-3 mol = 7.4e-3 mol; 4.4e21 ions





(b) Al2(SO4)3 --%26gt; 2 Al[3+] + 3 SO4[2-]


FW of Al2(SO4)3 = 342.15 g/mol


moles Al2(SO4)3 = 434 ml * 3.94 g/L * (1 mol / 342.15 g) * (1 L / 1000 ml) = 0.0050 mol


3+ ions: 2 * 0.0050 mol = 0.01 mol; 0.01 mol * 6.023e23 = 6.023e21 ions


2- ions: 3 * 0.0050 mol = 0.015 mol; 0.015 mol * 6.023e23 = 9.0e21 ions





(c) LiNO3 --%26gt; Li[1+] + NO3[1-]


??