Isotopes of an element have same atomic number (number of protons) but vary in the mass number (number of neutrons). The chemical reactivity of an element is not affected by the change in mass number. So, for stable isotopes of Oxygen, (Oxygen-16, Oxygen-17 and Oxygen-18) the biochemical pathway of oxygen breathed in during respiration remains unaffected even with different isotopes. Only the radioactive isotopes of oxygen when breathed in may cause serious health hazards as they emit radiations that may damage the internal organs in the body.
Answer:
C.
Explanation:
It's the only one that seems most reasonable i hope this helps
Billions of years ago, according to the theory of evolution, chemicals randomly organized themselves into a self-replicating molecule. This spark of life was the seed of every living thing we see today (as well as those we no longer see, like dinosaurs). That simplest life form, through the processes of mutation and natural selection, has been shaped into every living species on the planet.
Answer: the certain of a 10ml pipet is listed as, 10.00 0.02,
Explanation: those numbers are close to 4 significant figures as in (10ml) around the amount you're looking for. , hope that makes sense!
Answer: 
Explanation:

cM 0 0
So dissociation constant will be:

Given: c = 0.15 M
pH = 1.86
= ?
Putting in the values we get:
Also ![pH=-log[H^+]](https://tex.z-dn.net/?f=pH%3D-log%5BH%5E%2B%5D)
![1.86=-log[H^+]](https://tex.z-dn.net/?f=1.86%3D-log%5BH%5E%2B%5D)
![[H^+]=0.01](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D0.01)
![[H^+]=c\times \alpha](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3Dc%5Ctimes%20%5Calpha)


As ![[H^+]=[ClCH_2COO^-]=0.01](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D%5BClCH_2COO%5E-%5D%3D0.01)

![K_a=1.67\times 10^{-3]](https://tex.z-dn.net/?f=K_a%3D1.67%5Ctimes%2010%5E%7B-3%5D)
Thus the vale of
for the acid is 