15g of calcium hydroxide is dissolved in 500cm^3 of water 300cm^3 of the solution is used to neutralise hydrocloric acid of/5mol.dm^3 how do i calculate the volume of the acid
15 g Ca(OH)2 = ? mols.
That's 15/molar mass Ca(OH)2 = 15/74 = estimated 0.2
You used how many mols for the neutralization? That's 0.2 x (300/500) = estimated 0.12 mol Ca(OH)2.
The equation is
Ca(OH)2 + 2HCl ==> CaCl2 + 2H2O
If you neutralize 0.12 mols Ca(OH)2 it will required 0.24 mols HCl.
Then M HCl = mols HCl/L HCl. You know mols HCl and M HCl, solve for L HCl and convert to mL or whatever using you want. Check all of this.
To calculate the volume of the hydrochloric acid, you need to use the principle of stoichiometry and the balanced chemical equation for the neutralization reaction between calcium hydroxide (Ca(OH)2) and hydrochloric acid (HCl).
The balanced chemical equation for this reaction is:
Ca(OH)2 + 2HCl -> CaCl2 + 2H2O
From the equation, you can see that 1 mole of calcium hydroxide reacts with 2 moles of hydrochloric acid. Therefore, you can determine the number of moles of hydrochloric acid using the following formula:
moles of hydrochloric acid = moles of calcium hydroxide × (2 moles of hydrochloric acid / 1 mole of calcium hydroxide)
First, calculate the moles of calcium hydroxide:
moles of calcium hydroxide = mass of calcium hydroxide / molar mass of calcium hydroxide
The molar mass of calcium hydroxide (Ca(OH)2) can be calculated by summing the atomic masses of each element:
Molar mass of Ca(OH)2 = (40.08 g/mol) + 2 × (16.00 g/mol) + 2 × (1.01 g/mol) = 74.09 g/mol
Given that the mass of calcium hydroxide is 15 g:
moles of calcium hydroxide = 15 g / 74.09 g/mol
Next, calculate the moles of hydrochloric acid:
moles of hydrochloric acid = moles of calcium hydroxide × (2 moles of hydrochloric acid / 1 mole of calcium hydroxide)
Once you have found the moles of hydrochloric acid, you can determine the volume of hydrochloric acid using the following equation:
volume of hydrochloric acid = moles of hydrochloric acid / concentration of hydrochloric acid
Given that the concentration of hydrochloric acid is 0.5 mol/dm^3 and you want to find the volume in cm^3, you need to convert the concentration to mol/cm^3:
concentration of hydrochloric acid = 0.5 mol/dm^3 × (1 dm^3 / 1000 cm^3) = 0.5 mol/1000 cm^3 = 0.0005 mol/cm^3
Finally, substitute the values into the equation to calculate the volume of hydrochloric acid:
volume of hydrochloric acid = moles of hydrochloric acid / concentration of hydrochloric acid
Remember, only 300 cm^3 of the solution was used to neutralize the acid, so the volume of hydrochloric acid will be less than 300 cm^3.