a solution containing 4.2g KOHand Ca(OH) 2 is neutralized by an acid. it consumes 0.1 equivalent of acid, calculate the percentage composition of the sample
To calculate the percentage composition of the sample, we need to determine the amount of each component present in the solution. Let's break down the steps to find the answer:
1. Determine the moles of each component:
- For KOH: we have 4.2g. The molar mass of KOH is 56.11 g/mol (39.10 g/mol for K + 16.00 g/mol for O + 1.01 g/mol for H). Therefore, the moles of KOH = mass / molar mass = 4.2 g / 56.11 g/mol = 0.075 moles.
- For Ca(OH)2: we don't have the mass, so we need to find it. The molar mass of Ca(OH)2 is 74.10 g/mol for Ca + 2 * (16.00 g/mol for O + 1.01 g/mol for H) = 74.10 g/mol + 32.02 g/mol = 106.12 g/mol. Since we have the number of moles of KOH consumed by the acid reaction (0.1 equivalent of acid), and they react in a 1:1 ratio, the moles of Ca(OH)2 = 0.1 moles.
2. Calculate the total moles of the solution:
- Total moles = moles of KOH + moles of Ca(OH)2 = 0.075 moles + 0.1 moles = 0.175 moles.
3. Determine the percentage composition of each component:
- % composition of KOH = (moles of KOH / total moles) * 100 = (0.075 moles / 0.175 moles) * 100 = 42.9%.
- % composition of Ca(OH)2 = (moles of Ca(OH)2 / total moles) * 100 = (0.1 moles / 0.175 moles) * 100 = 57.1%.
Therefore, the percentage composition of the sample is approximately 42.9% KOH and 57.1% Ca(OH)2.