K12 4.03 Heat Lab (PLEASE HELP) [30 POINTS] (REAL ANSWERS, please)

I can't find the enthalpy of fusion for one of my trials. Info I have: 3,160 heat absorbed and 55g of ice melted (410g for the calorimeter w/ nothing -- 452g in the calorimeter w/ water -- 500g in the calorimeter w/ ice and water -- then I poured out the water after stirring and got 445g for the remaining ice). Also, I'm not sure what it means when it says I need to find the percent error from the accepted enthalpy of fusion of water of 334 J/g?

1. suppose a reaction mixture, when diluted with water, afforded 300 ml of an aqueous solution of 30 g of the reaction product malononitrile [ch2(cn)2], which is to be isolated by extraction with ether. the solubility of malononitrile in ether at room temperature is 20.0 g/100 ml, and in water is 13.3 g/100 ml. what weight of malononitrile would be recovered by extraction with (a) three 100-ml portions of ether and (b) one 300-ml portion of ether? suggestion: for each extraction, let x equal the weight extracted into the ether layer. in part (a), the concentration in the ether layer is x/100 and in the water layer is (30 x)/300; the ratio of these quantities is equal to k 20/13.3.