After 48.24 days, 1.56 g of a sample of I-131 remains. What was the original mass of the sample?

For which one of the following reactions is the value of δh° rxn equal to δh° f for the product? a. 2 h2 (g) + o2 (g) → 2 h2o (l) b. n2 (g) + o2 (g) → 2 no (g) c. 2 h2 (g) + o2 (g) → 2 h2o (g) d. h2o (l) + 1/2 o2 (g) → h2o2 (l) e. none of the above

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?

Joan writes four numbers on the board in standard form, and then she writes their scientific notation