Can someone help me to answer this correctly, please, and explain it. Please answer these 2 short questions, I don't have more money to buy more questions. These 2 questions are different.

1. a.

1. b.

A sample of a substance with the empirical formula XBr2 weighs 0.4302g. When it is dissolved in water and all its bromine is converted to insoluble AgBr by addition of an excess of silver nitrate, the mass of the resulting AgBr is found to be 0.7493g. The chemical reaction is XBr2+2AgNO32AgBr+X(NO3)2 (a) Calculate the formula mass of XBr2. FormulamassXBr2=gmol1 (b) Calculate the atomic mass of X. Atomic mass X= gmol1 Automobiles are often implicated as contributors to global warming because they are a source of the greenhouse gas CO2. How many pounds of CO2 would your car release in a year if it was driven 110. miles per week? Gasoline is a complex mixture of hydrocarbons. In your calculations, assume that gasoline is isooctane (molecular formula C8H18 ) and that it is burned completely to CO2 and H2O in the engine of your car. Also assume that the car averages 21.5. miles per gallon and that the density of isooctane is 0.692g/cm3. Pounds of CO2 released = Ibs