Which two atoms represent isotopes of the same element

How many grams of oxygen gas are contained in a 15 l sample at 1.02 atm and 28°c? show your work.

Some animals that try to adapt to climate changes eventually die due to starvation, as climate change alters the web.

Molecular iodine, i2(g), dissociates into iodine atoms at 625 k with a first-order rate constant of 0.271 s−1. part a part complete what is the half-life for this reaction?