The element in the top left corner of the periodic table is _____________

To calculate the mass percentage of $Tl_2SO_4$ in the sample it is necessary to know the mass of the solute ( $Tl_2SO_4$ in this case), and the mass of the solution (pesticide sample, whose mass is explicit in the letter of the problem).

To calculate the mass of the solute, we must take the mass of the $TlI$ precipitate. We can establish a relation between the mass of $TlI$ and $Tl_2SO_4$ using the stoichiometry of the compounds:

$moles\ of\ TlI = \frac{0.1824 g}{331.27\frac{g}{mol} } = 5.51*10^{-4}\ mol.$

Since for every mole of Tl in $TlI$ there are two moles of Tl in $Tl_2SO_4$ , we have:

$moles\ of\ Tl_2SO_4 = 2 * moles\ of\ TlI = 1,102*10^{-3}\ mol$

Using the molar mass of $Tl_2SO_4$ we have:

$mass\ of\ Tl_2SO_4 = 1,102*10^{-3}\ mol * 504.83\ \frac{g}{mol}= 0.56\ g$

Finally, we can use the mass percentage formula:

$mass\ percentage = (\frac{solute\ mass}{solution\ mass} )*100 = (\frac{mass\ of\ Tl_2SO_4}{pesticide\ sample\ mass})*100 = (\frac{0.56g}{9.486g})*100 = 5.86\%$

6 0

2 years ago

A lab is done using different metals and the density of the metals are recorded in a data table. What is the independent variabl

vovikov84 [41]

Answer: The independent variable is the type of metal being used.

{Note: The "dependent variable" is the "measured density" that corresponds to each of the metals."}.

___________________________________________

Explanation:

___________________________________________

The "independent variable", which is plotted on the "x-axis" (horizontal axis), is the variable that can be "controlled/manipulated". In this case, this would be the type of metal chosen.

The "dependent variable" , which is plotted on the "y-axis" (vertical axis) is the "obtained value/measurement/result" (that "cannot be controlled/manipulated").

In this case, the "density", which is the "measured value" that corresponds to the selected "meal", is the "dependent variable".

___________________________________________

Hope this helpful to you!

Wishing you well!

___________________________________________

6 0

3 years ago

The element in the top left corner of the periodic table is ______________.answer: