Silver chloride is virtually insoluble in water so that the reaction appears to go to completion. How many grams of solid NaCl must be added to 25.0 mL of 0.366 M AgNO3 solution to completely precipitate the silver

0.535 g

Explanation:

The reaction that takes place is:

First we calculate how many AgNO₃ moles are there in 25.0 mL of a 0.366 M solution, using the definition of molarity:

Converting 25.0 mL to L ⇒ 25.0 / 1000 = 0.025 L

Then we convert AgNO₃ moles into NaCl moles:

Finally we convert NaCl moles into grams, using its molar mass:

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.