Given the following equation and bond energies, determine which statement is true. n2 + o2 → 2no n-n triple bond: 941 kj/mol o-o double bond: 495 kj/mol n-o bond: 201 kj/mol
a. a nitrogen-oxygen bond is broken.
b. the reaction is exothermic.
c. the products have more energy than the reactants.
d. a triple bond between nitrogen atoms is formed.

The chart shows the bid provided by four contractors to complete a job. which contractor is the most cost-effective?

What is the ph of a solution that has a hydrogen ion concentration of 1.0 * 10 -9 m?

For a research project, a student decided to test the effect of the lead(ii) ion (pb2+) on the ability of salmon eggs to hatch. this ion was obtainable from the water‐soluble salt, lead(ii) nitrate, which the student decided to make by the following reaction. pbo(s) + 2 hno3(aq) → pb(no3)2(aq) + h2o losses of product for various reasons were expected, and a yield of 86.0% was expected. in order to have 5.00 g of product at this yield, how many grams of pbo should be reacted? (assume that sufficient nitric acid, hno3, would be used.)