A 1.850 g mixture of SrCO3 and SrO is heated. The SrCO3 decomposes to SrO and CO2. What was the mass percentage of SrCO3 in the mixture if the mass after heating is 1.445 g?

Question

aaronq · Answer

i can't think of a way to explain it without giving you the answer, but i'll try to give you a hint.

so the process is: $SrCO_3\rightarrow SrO+CO_{2~(g)} $

you know that you had a mixture, and you lost some mass. The mass that was lost was form the CO2 gas that escaped and it was only contributed by $SrCO_3$. 

you can use that mass to trace back how much $SrCO_3$ there was initially.

HINT: you will need the molar mass of $CO_2$ and of  $SrCO_3$.

anonymous · Answer

Okay the molar mass of CO2 is 44 and SrCO3 is 147.62 but I don't see where to go from there.

anonymous · Answer

This mass percentage question came out of nowhere. I don't even know the process to follow.

aaronq · Answer

hm okay. find the mass of the sample lost. That is the mass of CO2, convert it to moles. The moles of CO2 are equal to the moles of $SrCO_3$ (because their stoichiometric coefficients are the same in the above equation (which is balanced). So use the moles and molar max to find the mass of $SrCO_3$. Then you can use that and the total mass (1.85 g) to find it's percentage.

aaronq · Answer

molar mass** not max

anonymous · Answer

okay. i have to go but I will be back. Hopefully I will be able to contact you later lol. in case i can't thank you very much for the help.

aaronq · Answer

no problem. If i'm not around someone who can help you will probable be. good luck