chemistry problems!help!?

[Angie L]

1.) A solution is prepared by dissolving 2.50 g of K2CrO4 in 23.2g of water. Calculate the molality of K2CrO4.

2.) How many kilograms of water must be added to a 9.0g of H2C2O4, to prepare a .025 molality solution?

3.) A saturated solution of NaCl at 30degrees C has a molality of 6.25m. What is the mole fraction and mass fraction of NaCl in the solutuon?

4.)a .50 molal solution of an unknown compound in water freezes at -1.86degreesC. Is the compound most likely to be molecular or ionic? Why?

5.) A solution containing 16.9g of a nonvolatile molecular compound in 250g of water has a freezing point of -.744degreesC. What is the molecular mass of the substance?

Please show steps and procedure! THANKSSSS!!