Calculate the number of moles of MgO if the mass of MgO (magnesium oxide) is 50 g? Please help... I will mark the answer with brainlist...
 

An atom of lithium-7 has an equal number of(1) electrons and neutrons(2) electrons and protons(3) positrons and neutrons(4) positrons and protons

Select all that apply. using a value of ksp = 1.8 x 10-2 for the reaction pbcl2 (s) pb+2(aq) + 2cl -(aq). the concentration of the products yield a ksp of 2.1 x 10-2:

Iwould appreciate if someone could me.