Answer:
Explanation: that decays by emitting an electron particle the resulting nuclide is zinc-64. and yeah
The atomic number defines the number of protons in an atom.
Answer: 2 molecules of ammonia
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
The balanced chemical equation for the formation of ammonia is:

According to stoichiometry,
3 molecules of hydrogen combines with 1 molecule of nitrogen to give 2 molecules of ammonia.
Answer:
547.5g
Explanation:
To get the mass, you need moles.
moles = (molarity)(Liters)
moles = (1.230M)(4.200L) = 5.166 moles Na2CO3
Now, just use stoichiometry
molar mass of Na2CO3 = 2(mass of Na) + (mass of C) + 3(mass of O)
= 2(22.9) + 12.01 + 3(16) = 105.99g/mol
5.166moles(105.99g/mol)
= 547.544
But, the measurements given had 4 significant figures, so in chemistry we write:
547.5g