Question

“A solution is made by dissolving 26.42 g of (NH4)2SO4 in enough H2O to make 50.00 mL of solution. What is the molar mass of (NH4)2SO4? What is the molarity of this solution? ” I have trouble understanding them. Please help

Answer 1

to calculate the molar mass you have to add all the "atomic mass" of the atoms in the molecule in their respectively proportions. The atomic mass for each element can be found in a periodic table

Answer 2

in your case
you have to look in the periodic table the atomic mass for each of the follow elements (it looks like a 4-5 digit number 23.453)

N= ?
H=?
S=?
O=?
then multiply that values by the number os atoms of each element you have in the molecule
atomic mass of O x 4 = ?