Write the formula for each of the following compounds: a. sulfur difluoride b. sulfur hexafluoride c. sodium dihydrogen phosphate d. lithium nitride e. chromium(iii) carbonate f. tin(ii) fluoride g. ammonium acetate h. ammonium hydrogen sulfate i. cobalt(iii) nitrate j. mercury(i) chloride k. potassium chlorate l. sodium hydride

a. sulfur difluoride SF₂

b. sulfur hexafluoride SF₆

c. sodium dihydrogen phosphate NaH₂PO₄

d. lithium nitride Li₃N

e. chromium(III) carbonate Cr₂(CO₃)₃

f. tin(II) fluoride SnF₂

g. ammonium acetate NH₄(CH₃COO)

h. ammonium hydrogen sulfate NH₄(HSO₄)

i. cobalt(III) nitrate Co(NO₃)₃

j. mercury(I) chloride Hg₂Cl₂

k. potassium chlorate KClO₃

l. sodium hydride NaH

Explanation:

The names give us information about the composition. First, we mention the cation  and then the anion. In the formula, we follow the same order. Each part has a charge but the resulting compound is electrically neutral.

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.  

the awnser is group 12