[Steved]

Hello, I am working on two problems, one  having to do with heat in reactions and the other with heating/cooling curve.  The first one asks "The formation of rust (Fe₂O₃) from solid Iron and Oxygen gas releases 1.7 * 10³ kJ.

4Fe(s) + 3O₂(g) ------> 2Fe₂O₃. With -1.7 * 10³kJ

How many grams of rust form when 150 kcal are released.

The other question is:  How many kilojoules of heat are released when 85.0 grams of steam at 100 degrees celsius is converted to liquid water at 15 degrees celsius.

Thanks a lot for your help.

[Yggdrasil]

Please read the Forum Rules[/url].  You must show your attempt at answering the question before we will help you.  However, here are some guiding questions:

Do you know how to convert kcal to kJ?  How much heat is released when 1 mol of rust is formed?

For the second question, first calculate the heat needed to condense 8.5g of steam at 100^oC into 8.5 g of steam at 100^oC.  Then calculate the amount of heat released when the water cools from 100 to 15 degrees.