When are elements heavier than iron formed by stars?(1 point) 1. in small, old stars
2. as a dying star explodes
3. as a star is first formed
4. in young stars

What element breaks down into yttrium-90?

Achemistry student needs to standardize a fresh solution of sodium hydroxide. he carefully weighs out of oxalic acid , a diprotic acid that can be purchased inexpensively in high purity, and dissolves it in of distilled water. the student then titrates the oxalic acid solution with his sodium hydroxide solution. when the titration reaches the equivalence point, the student finds he has used of sodium hydroxide solution.calculate the molarity of the student's sodium hydroxide solution. be sure your answer has the correct number of significant digits.

Nitrogen dioxide decomposes according to the reaction 2 no2(g) ⇌ 2 no(g) + o2(g) where kp = 4.48 × 10−13 at a certain temperature. if 0.70 atm of no2 is added to a container and allowed to come to equilibrium, what are the equilibrium partial pressures of no(g) and o2(g)