The half-life of uranium-235 is 700 million years, if there is 1000g of urnanium-235 in the original sample, what happens after 2100 million years have passed?

Determine the percent sulfuric acid by mass of a 1.61 m aqueous solution of h2so4. %

Can someone me with questions 12 and 13 plz.

Select the correct text in the passage. which sentences describe examples of sustainable living? i live in an old apartment building downtown, but my company is based in an office park on the outskirts of the city. i drive an old car that needs to be replaced. i plan to buy a hybrid for better gas mileage, but for now i am able to carpool with a couple of friends from work. the drive to the office park is about 45 minutes each way, but we do get to work in a modern building. the architects just received a leed certification for the design.