S(s) + O2 (g) --> SO2 (g) Change in heat is -296 kJ/mol
a) How much heat is evolved when 275g sulfur is burned in excess O2?
b) How much heat is evolved when 25mol sulfur is burned in excess O2?
Can someone help me out on this and show me a step by step process on how to solve this?
2007-11-01 17:02:04 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
a) look at you formula. Delta heat is in kJ/mole, so your first step is to figure out how many mole are in 275g of sulfur. Atomic wt of S is 32.065(5) g·mol−1 so there is 0.12 moles of S present. Times delta heat by .12 moles, remember to cancel units, and you get -35.53 kJ.
b) even easier as we don't have to do dimensional conversion. Time -295 kJ/mole by 25 mole and get -7400 kJ.
Hope that was right.
2007-11-01 17:11:32 · answer #1 · answered by No Drama 3 · 0⤊ 0⤋
Convert 275 g to g-atoms of sulfur. Then multiply by the -296 kj/mole.
Multiply 25 x -296 kj/mole.
IMPORTANT: The units of heat are kilojoules PER MOLE. So if you have 2 moles, you have twice the heat and so on.
2007-11-01 17:05:51 · answer #2 · answered by cattbarf 7 · 0⤊ 0⤋