Can some one help me with this science quiz

What is the mass of 0.46 mil of mgcl2

Calculate the number of kilojoules to warm 125 g of iron from 23.5°c to 78.0°c.

For the reaction shown, calculate how many moles of no2 form when each of the following completely reacts. 2n2o5(g)→4no2(g)+o2(g) part a 1.0 mol n2o5 express your answer using two significant figures. nothing mol m o l request answer part b 5.4 mol n2o5 express your answer using two significant figures.