Answer: 1 mole of 
has the greatest mass.
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP , contains avogadro's number 
of particles and weighs equal to the molecular mass of the substance.
1 mole of has a mass of 40 g.
1 mole of 
has a mass of 28 g
1 mole of 
has a mass of 32 g
1 mole of 
has a mass of 16 g.
1 mole of 
has a mass of 30 g.
Thus the greatest mass is of 1 mole of
<span>Each liquid boils only at a certain temperature, which is called its </span><span>Boiling Point
Water for example has a boiling point of 100 degrees Celsius.</span>
(2) Arsenic. It is an element and elements are chemically the simplest units and cannot be broken down by any chemical change.
Gold has a heavy enough nucleus that its electrons must travel at speeds nearing the speed of light to prevent them from falling into the nucleus. This relativistic effect applies to those orbitals that have appreciable density at the nucleus, such as s and p orbitals. These relativistic electrons gain mass and as a consequence, their orbits contract. As these s and (to some degree) p orbits are contracted, the other electrons in d and f orbitals are better screened from the nucleus and their orbitals actually expand.
Since the 6s orbital with one electron is contracted, this electron is more tightly bound to the nucleus and less available for bonding with other atoms. The 4f and 5d orbitals expand, but can't be involved in bond formation since they are completely filled. This is why gold is relatively unreactive.
Hope it helps
Answer is: the molarity of a solution is 0.276 M.<span>
V(solution) = 855 mL </span>÷ 1000 mL/L.
V(solution) = 0.855 L.
m(NH₄NO₃) = 18.9 g; mass of ammonium nitrate.
M(NH₄NO₃) = 80.04 g/mol; molar mass of ammonium nitrate.
n(NH₄NO₃) = m(NH₄NO₃) ÷ M(NH₄NO₃).
n(NH₄NO₃) = 18.9 g ÷ 80.04 g/mol.
n(NH₄NO₃) = 0.236 mol; amount of substance.
c(NH₄NO₃) = n(NH₄NO₃) ÷ V(solution).
c(NH₄NO₃) = 0.236 mol ÷ 0.855 L.
c(NH₄NO₃) = 0.276 mol/L; molarity of ammonium nitrate.
