What is the total number of atoms contained in 50.0 grams of Helium?

7. what temperature is need to just dissolve 50 g of nh4cl in 75 g of water? '

Explain the relationship between forward and backward reactions in equilibrium, and predict how changing the amount of a reactant (creating a tension) will affect that relationship.

There is one girl i like and i don't know how to tell her that, i have a feeling she knows but if she doesn't i don't want to make a fool out of myself how is one way to boost my confidence on asking her out