To make NaTcO4, Tc metal is dissolved in nitric acid to make HTcO4, NO2 and H2O. Then the product HTcO4 is treated with NaOH to make NaTcO4. If you begin with 4.5 mg of Tc metal, how much of NaOH (in grams) is required to convert all of the HTcO4 into NaTcO4?
I don't even know what equation to use or where to start. There doesnt seem to be enough information given in the problem. Plz help me if you can!
Thanks!
There is more than enough information in the question.
First start with the two equations.
Tc + HNO3 = HTcO4 + NO2 + H2O (needs to be balanced)
HTcO4 + NaOH = NaTcO4 + H2O (this is balanced)
from the second equation we see that 1 mole of NaOH reacts with 1 mole of HTcO4. So if we find the number of moles of HTcO4 produced this is also the number of moles NaOH needed.
Once you have balanced the first equation you can calculate the number of moles of Tc metal used, hence the number of moles of HTcO4 produced.
Hope this helps.
To solve this problem, let's first determine the molar mass of Tc metal using the periodic table. Tc has an atomic mass of approximately 98 g/mol.
Next, we need to convert the mass of Tc metal (4.5 mg) into moles. To do this, divide the mass by the molar mass:
4.5 mg = 4.5 × 10^(-6) g
4.5 × 10^(-6) g Tc ÷ 98 g/mol = ...
Calculating the result, we find that we have approximately 4.6 × 10^(-8) moles of Tc.
Since the stoichiometry of the reaction is 1:1 between HTcO4 and NaTcO4, we'll need an equal number of moles of NaOH to convert all of the HTcO4 into NaTcO4. Therefore, we need to determine the mass of NaOH required.
The molar mass of NaOH is approximately 40 g/mol. Using this information and the number of moles of Tc, we can calculate the mass of NaOH needed:
4.6 × 10^(-8) mol NaOH × 40 g/mol = ...
Evaluating this expression, we find that approximately 1.84 × 10^(-6) grams of NaOH is required to convert all of the HTcO4 into NaTcO4.
Please note that this calculation assumes that all reactions proceed to completion and that there are no other limiting factors in the reaction.