Classify each of the substances as an atomic element, molecular element, molecular compound, or ionic compound. Provide one sentence explanation for each. a. fluorine b. N2 O c. silver d. K2 O e. Fe2 O3 g

Answer and Explanation:

a. fluorine ⇒ atomic element

Fluorine (F) is a chemical element because it is a pure substance that cannot be decomposed into simpler substances.

b. N₂O ⇒ molecular compound

We can see that N₂O (nitrous oxide) is a molecule composed by two different atomic elements: nitrogen (N) and oxygen (O). Thus, it is a molecular compound.

c. silver ⇒ atomic element

Silver is a chemical element with the symbol Ag. It is a pure substance which cannot be decomposed into simpler substances.

d. K₂O ⇒ ionic compound

Potassium oxide (K₂O) is composed by a metallic element (potassium, K) and a non-metallic element (O). Thus, there is a difference in the electronegativity of the chemical elements, so the substance can dissociate into ions. In consequence, it is an ionic compound.

e. Fe₂O₃ ⇒ molecular compound (with ionic character)

Iron(III) oxide (Fe₂O₃) is composed by iron element (Fe), which is a metal, and oxygen element (O), which is a non-metal. Since it is a Metal- Non-Metal combination, it would be an ionic compound. The difference in electronegativity between Fe and O is not high (<2.0) in comparison with other ionic compounds, so Fe₂O₃ is considered as a polar covalent compound (it is between an ionic compound and a molecular compound).

First off, we need to write out the balanced chemical equation for this reaction (include states too!),

2NaOH(aq) + H2SO4(aq) --> Na2SO4(aq) + 2H2O(l)

We are given that NaOH is 210g

Figure out the moles,

n=m/M
  =210 / 2(22.99) + 2(16) + 2(1.008)
  =2.625...

Now look back at the chemical equation, the mole ratio from NaOH and Na2SO4 is 2:1

So divide the moles of NaOH by 2 to get the moles of Na2SO4

You get, n=1.312...

Use n=m/M again to find the mass of Na2SO4

1.312.. = m / 2(22.99) + 32.06 + 4(16)
m = 1.312.. x (2(22.99) + 32.06 + 4(16)) 
    = 186.4g (1 d.p)

Therefore, mass of Na2SO4 (sodium sulfate) is 186.4g

HOPE THIS HELPED!