Question

calculate the molarity of a solution prepared by dissolving 11.5g of naoh in enough water to give 1.0l of solution. (hint: first calculate the molar mass of naoh: na = 22.99amu; o=16.00amu, h=1.008 amu. then, convert 11.5 g to moles to get molarity in moles per liter).

1. 460 m
2. 0.288m
3. 0.144m
4. 11.5m

Explanation:

Step1: Calculate molar mass of NaOH

Molar mass of NaOH = mass of Na + mass of O + mass of H = \(22.99 + 16.00 + 1.008 = 39.998\space g/mol\) (approx \(40.00\space g/mol\))

Step2: Convert grams to moles

Moles of NaOH = \(\frac{mass}{molar\space mass}=\frac{11.5\space g}{39.998\space g/mol}\approx0.2875\space mol\)

Step3: Calculate molarity

Molarity \(M = \frac{moles\space of\space solute}{volume\space of\space solution\space (L)}=\frac{0.2875\space mol}{1.0\space L}\approx0.288\space M\)

Answer:

1. 0.288M