Magnesium + Sulfuric acid

What is the formula that this ionic compounds could form sr2+p3-o2-

24. a sports ball is inflated to an internal pressure of 1.85 atm at room temperature (25 °c). if the ball is then played with outside where the temperature is 7.5 °c, what will be the new pressure of the ball? assume the ball does not change in volume nor does any air leak from the ball a) 0.555 atm b) 1.74 atm c) 1.85 atm d) 1.97 atm

Calculate the mass of silver needed to react with chlorine to produce 126g if silver chloride?