Answer: Number of molecules of hydrogen gas 
Explanation:

Number of moles of sodium =
According to reaction , 2 moles of sodium produces 1 mole of hydrogen gas , then 2.11 mol of sodium will=
of hydrogen gas that is 1.05 moles of hydrogen gas.
Number of molecules =
moles of substance
Moles of hydrogen gas formed = 1.05 moles
Number of molecules of hydrogen gas =
moles of hydrogen gas
Number of molecules of hydrogen gas 
The ionic compound for AlBr3 is ↓
Aluminum Bromide
Answer:
Write this in a word and skeleton equation:
Solid silver chloride and an aqueous solution of nitric acid are produced when a solution of silver nitrate is reacted with a solution of hydrochloric acid.
Explanation:
Knowing the ratio between atoms we can write an empirical formula:
<span>C4H6O </span>
<span>we compute the molar mass of this single formula: </span>
<span>4x12 + 6 x 1 + 16 x1 = 70 g / mol </span>
<span>Now, as we know the actual molar mas being 280 g/mol, we divide this number by 70 and we get the ratio between empirical formula and molecular actual formula: </span>
<span>280 / 70 = 4 </span>
<span>This means that actual molecular formula is: </span>
<span>(C4H6O)4 or </span>
<span>C16H24O4 </span>