Answer
(a) 25.0 g
(b) 67.6 g
Work Step by Step
(a)
1. Find the number of moles:
$Concentration(M) = \frac{n(mol)}{V(L)}$
$1.25 = \frac{n(mol)}{0.5}$
$1.25 * 0.500 = n(mol)$
$0.625 moles = n(mol)$
2. Determine the molar mass of this compound (NaOH):
22.99* 1 + 16* 1 + 1.008* 1 = 39.998g/mol
3. Calculate the mass
$mm(g/mol) = \frac{mass(g)}{n(mol)}$
$mm(g/mol) * n(mol) = mass(g)$
$ 39.998 * 0.625 = mass(g)$
$25.0 = mass(g)$
(b)
1. Find the number of moles:
$Concentration(M) = \frac{n(mol)}{V(L)}$
$0.250 = \frac{n(mol)}{1.5}$
$0.250 * 1.50 = n(mol)$
$0.375 moles = n(mol)$
2. Determine the molar mass of this compound ($C_6H_{12}O_6$):
12.01* 6 + 1.008* 12 + 16* 6 = 180.156g/mol
3. Calculate the mass
$mm(g/mol) = \frac{mass(g)}{n(mol)}$
$mm(g/mol) * n(mol) = mass(g)$
$ 180.156 * 0.375 = mass(g)$
$67.6 = mass(g)$
