Answer
a. The molarity of this solution is equal to 0.500 M glucose.
b. 0.0356 M $KOH$ solution
c. This is a $0.250$ NaCl solution
Work Step by Step
a. $$Molarity(M) = \frac{moles \space of \space solute}{liters \space of solution}$$
$$= \frac{2.00 \space moles \space glucose}{ 4.00 \space L \space solution} = 0.500 \space M \space glucose \space solution$$
b.
- Calculate or find the molar mass for $ KOH $:
$ KOH $ : ( 1.008 $\times$ 1 )+ ( 16.00 $\times$ 1 )+ ( 39.10 $\times$ 1 )= 56.11 g/mol
- Using the molar mass as a conversion factor, find the amount in moles:
$$ 4.00 \space g \times \frac{1 \space mole}{ 56.11 \space g} = 0.0713 \space mole$$
- Write the molarity expression and evaluate it:
$$Molarity(M) = \frac{moles \space of \space solute}{liters \space of \space solution}$$
$$= \frac{0.0713 \space mole \space KOH}{ 2.00 \space L \space solution} = 0.0356 \space M \space KOH \space solution$$
c.
- Calculate or find the molar mass for $ NaCl $:
$ NaCl $ : ( 22.99 $\times$ 1 )+ ( 35.45 $\times$ 1 )= 58.44 g/mol
- Using the molar mass as a conversion factor, find the amount in moles:
$$ 5.85 \space g \times \frac{1 \space mole}{ 58.44 \space g} = 0.100 \space mole$$
$1 \space L = 1000 \space mL$
$$Volume(L) = 400. \space mL \times \frac{1 \space L}{1000 \space mL} = 0.400 \space L$$
- Write the molarity expression and evaluate it:
$$Molarity(M) = \frac{moles \space of \space solute}{liters \space of \space solution}$$
$$= \frac{0.100 \space mole \space NaCl}{ 0.400 \space L \space solution} = 0.250 \space M \space NaCl \space solution$$
