16. Circle the letter of each chemical equation that is balanced.
a. H2 + O2 + H2O
b. Mg + O2 + Mgo
c. Na + O2 → Na20
d. 2 H2O2 → 2 H2O + O2
(How are you posted to know help please I don't get it...)

d

Explanation:

a) This is not an equation.

b) This is not an equation.

c) The reactant side has 1 Na and 2 O while the product side has 2 Na and 2 O, therefore it is not balanced

d) The reactant side has 4 H and 4 O and the product side has 4 H and 4 O, therefore it is balanced.

the grams   of   barium that   are in   2.3 x 10^23   atoms of barium   is   52.4 g (answer c)

    calculation

mass = moles   of ba   x molar   mass of ba

  molar mass of ba from periodic table=   137.3 g/mol

  use the   avogadro's law   constant   to   calculate the moles of barium

  that   is     1 mole =   6.02   x 10^23 atoms

                    ? moles = 2.3 x 10^23   atoms

by cross   multiplication

=(1 mole   x 2.3x 10^23 atoms)   / 6.02   x10^23 atoms)=   0.382   moles

mass   is therefore = 137.3   g/mol x 0.382 mol = 52.4 ( answer c)

explanation: