A TUMS tablet was dissolved in 100.00 ml of 0.1805 M HCl and analyzed for CaCO3 according to the procedure described in the lab manual. It took 11 ml of 0.1491 M NaOH to reach the endpoint. Calculate the mass of CaCO3 in TUMS tablet to the correct number of significant .
I have no idea what procedure is described in your lab manual. Also, by mentioning s.f. makes me wonder if that is 11 mL or 11.00.
CaCO3 + 2HCl ==> CaCL2 + H2O + CO2
total mols HCl before rxn = M x L = ?
mols HCl left over after rxn = MNaOH x L NaOH = ?
mols HCl used in the rxn = total mols - mols left over.
Convert mols HCl used in the rxn to mols CaCO3 in the rxn by using the coefficients in the balanced equation.
Convert mols CaCO3 to grams. g = mols x molar mass = ?
Round to the correct number of s.f.
Ok, you put initially excess HCL, then back titrated with NaOH to enpoing
backpoint:
NaOH+HCl>>NaCl + H20
moles HCl titrated= molesNaOH
= .1419*.011=.00156
moles HCl left: moles orig-0.00156
= .100*.1805-.00156== 0.01649
and that HCL was used to titrate the original CaCO3
moles CaCO3=1/2 moles HCL used
=1/2 * 0.01649=.00825
grams CaCO3=.00825*100.1=.825 grams
So check my work. Regular tums have about .5grams, other sizes .75, and 1.0 grams, and 1.1 grams.
To calculate the mass of CaCO3 in the TUMS tablet, we first need to determine the moles of CaCO3 reacted with NaOH. Let's break down the problem step by step:
1. Calculate the moles of NaOH used:
We can use the given volume and concentration of NaOH to determine the moles of NaOH used in the reaction.
Moles of NaOH = volume (in liters) x concentration (in moles per liter)
Moles of NaOH = 0.011 L x 0.1491 mol/L
2. Calculate the moles of HCl that reacted with NaOH:
Since HCl and NaOH react in a 1:1 ratio, the moles of NaOH used is equal to the moles of HCl present in the initial solution.
Moles of HCl = Moles of NaOH = (0.011 L)(0.1491 mol/L)
3. Calculate the moles of CaCO3 reacted with HCl:
The reaction between HCl and CaCO3 can be represented by the balanced equation:
CaCO3 + 2HCl -> CaCl2 + H2O + CO2
From the balanced equation, we can see that for every 1 mole of CaCO3, 2 moles of HCl are required. Therefore, the moles of CaCO3 is half of the moles of HCl.
Moles of CaCO3 = (1/2) Moles of HCl = (1/2)(0.011 L)(0.1491 mol/L)
4. Calculate the mass of CaCO3:
To find the mass of CaCO3, we need to convert the moles of CaCO3 to grams using its molar mass.
The molar mass of CaCO3 can be calculated by summing the atomic masses of its constituent elements: Ca (40.08 g/mol), C (12.01 g/mol), and O (16.00 g/mol).
Molar mass of CaCO3 = (40.08 g/mol) + (12.01 g/mol) + (3 * 16.00 g/mol)
Mass of CaCO3 = Moles of CaCO3 x Molar mass of CaCO3
By plugging in the given values and performing the calculations, you can determine the mass of CaCO3 in the TUMS tablet to the appropriate number of significant figures.