A hydrate of Na2CO3 has a mass of 4.31 g before heating. After heating, the mass of the anhydrous compound is found to be 3.22 g. Determine the formula of the hydrate and then write out the name of the hydrate. Please show all your work for the calculations for full credit.

Question

aaronq · Answer

first: calculate the mass composition of Na2CO3

anonymous · Answer

105.9884?

aaronq · Answer

not molar mass, mass percent composition of each element

aaronq · Answer

but you will use the molar mass

aaronq · Answer

http://www.chem.tamu.edu/class/majors/tutorialnotefiles/percentcomp.htm

anonymous · Answer

i dont know how to do that then

aaronq · Answer

look at the link i posted

anonymous · Answer

do i have to divide the molar mass of carbon or the molar mass of sodium, by the molar mass of the compound?

aaronq · Answer

basically, but you have to take into account the amount of atoms of each species

anonymous · Answer

what do you mean?

aaronq · Answer

like if you have a bag of fruit (10g), but you have 2 bananas and each banana weighs 1 g

then, mass percent composition of bananas = mass bananas/total mass of fruit

2g/10g  x100%= 20 % 

same for sodium, you have 2 atoms of sodium in the molecule

mass percent composition of sodium =  (molar mass of sodium x2) / total molar mass

anonymous · Answer

43.38 = percent composition ?

aaronq · Answer

you actually don't need to find the mass percent composition (doesn't hurt to learn something new though, right? haha) im kinda busy at the moment, can you follow this? http://mglascience.cmswiki.wikispaces.net/file/view/Hydrates+HW.pdf

anonymous · Answer

not really but thanks anyway(:

aaronq · Answer

haha sorry!

anonymous · Answer

your fine!

aaronq · Answer

did you figure it out?

lena772 · Answer

@aaronq can you help me?