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To find the captionand solute (a simple caption) use the formula:T = m/V,where T is the titer; m – mass of the substance dissolved in the liquid, V is the volume of solution in milliliters or cubic centimeters.
In addition, the titer you will be able to calculate at the designated substance. This value is also called the conditional titerohms. This will require a formula: T (a/b) = mb/ Va,where T (a/b) is the titer of the solution of the substance a in substance b; mb is the mass of substance b(in grams) that interacts with the solution; Va is the volume of solution of the substance a (in milliliters).
For example, you need to find the titer of the solution of phosphoric acid weight 18 g, obtained by dissolving Н3РО4 in 282 ml of water. The density of the solution is equal to 1,031 g/ml. first, find the mass of the prepared solution, with 282 ml of water will equal 282 g: 28+282 = 300 (d). Then, calculate its volume: 300/ 1,031 = 291 (ml). Now substitute into the formula and find the caption: 18/291 = 0,0619(g/ml).
In addition to the above described methods, you can also calculate the titer, knowing the equivalent mass and normality (equivalent concentration).T = SN*MEq/1000,where T is the titer, SN – normality, MEq – equivalent mass.
Often you will encounter tasks that need to Express the titer of one substance through another. For example, this condition: the caption isa set of 20 ml hydrochloric acid solution with a titerof om 0,0035 g/ml had spent 25 ml of sodium hydroxide solution. It is necessary to calculate the titer of NaOH by HCl.
First, write the reaction equation: NaOH + HCl = NaCl + H2O. Then calculate the titer of alkali solution by the formula: T (NaOH) =T(HCl)*V(HCl)*M(NaOH) / M(HCl)*V(NaOH). Substituting numerical values, obtain the titer of sodium hydroxide equal 0,0031 g/ml. it Remains to calculate the necessary to solve the problem significance:T (NaOH/HCl) = T(NaOH)* MEq(HCl) / MEq(NaOH) =0,0028 g/ml
In spite of the same unit, never confuse the titer of the solution density. Because the value of the density indicates the mass of one cubic centimeter of the solution, not the mass of solute in it.