Ineed badly? ? it's scince and i can't figure it out..

Ted and emily played a mixed doubles tennis match against jack and brenda. in the second match. ted and brenda played against jack and emily. which type of chemical reaction does the situation demonstrate?

Determine the empirical formula for succinic acid that is composed of 40.60% carbon, 5.18% hydrogen, and 54.22% oxygen.

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