What do we call the mass of an element in a compond compared to the entire mass of the compound?

Seawater contains approximately 3.5%nacl by mass and has a density of 1.02 g/ml. what volume of seawater contains 7.5 g of sodium?

Select all of the methods through which a drug can enter your body. injection swallowing inhalation absorption

Which of the following nuclei would be the least stable a 2 protons, 2 neutrons b 1 proton 1 neutron c 1 proton 3 neutrons d 1 proton 2 neutrons