There are 18 Elements in the fifth period.
Here you go! There are 0.9307 moles in 123.0 g of the compound. I solved this by using a fence post method. I calculated the number of grams in one mol of (NH4)2 SO4 and got 132.16.
I did this by finding the atomic mass of each element on the periodic table (my work is in the color blue for this step)
After that, i divided the given mass by the mass of one mol of the compound.
The answer is 0.9307 moles!! I hope this helped you! :))
Physical property of gas:
There are a lot, here are some examples:
=> Air
=> Oxygen
=> Carbon dioxide
=> Flourine
=> Phosphine
=> Argon
=> Carbon monoxide
This examples are all gases and each of these gases has its own physical property. The only thing that they makes them the same are that, they are gas with lesser molecules. Usually gas density is lesser compare to the solid or liquid and most gases has undefined melting point.