[Naples]

In most of its ionic compounds, cobalt is either Co(II) or Co(III). One such compound, containing chloride ion and waters of hydration, was analyzed, and the following results were obtained. A 0.256-g sample of the compound was dissolved in water, and excess silver nitrate was added. The silver chloride was filtered, dried and weighed, and it had a mass of 0.308 g. A second sample of 0.416 of the compound was dissolved in water, and excess sodium hydroxide was added. The hydroxide salt was filtered and heated in a flame, forming cobalt(III) oxide. The mass of cobalt(III) oxide formed was 0.145g

a. what is the percent composition by mass of the compound?
b. Assuming the compound contains one cobalt atom per formula unit, what is the molecular formula?
c. Write a balanced equation for the three reactions described.

I have no idea where to start on this so any help is greatly appreciated

[Borek]

With reaction equations.