Percent composition by mass of oxygen =
((16.0*6)/(40.1+2*(14.0+16.0*3)))*100%
= 58.5%
therefore, the answer is D
Hello,
Your answer to this question would be Convection.
<span>Wind in the atmosphere and currents in the ocean are caused by uneven heating that produces convection.
Hope this helps</span>
We know that it is a certainty based on things such as the size, mass, brightness, etc. They can determine to within a relative level of accuracy the age. Of course they can be off by millions of years, but that’s pretty precise for a 10–20 billion year time period for the life of a star. BUT we absolutely cannot predict exactly when it will explode and we see supernovas in other galaxies, but the last one in the Milky Way that we observed was in the 1600s.
The reaction between zinc and hydrogen gas is:
Zn + H₂ → ZnH₂
So for every 1 mole of H₂ gas, it needs 1 mole of Zinc. The atomic weight of H2₂ is 2 g/mol, and Zinc is 67.425 g/mol. The density of H₂ at atmospheric pressure and at 293 K is 0.00016 g/mL. The solution is as follows:
Mass = Density*Volume = (0.00016 g/mL)(150 mL) = 0.024 g H₂
Moles H₂ = 0.024 g H₂ * 1 mol/2 g = 0.012 mol H₂
Thus, it also needs 0.012 mol Zn.
Mass of Zn needed = 0.012 mol * 67.425 g/mol = <em>0.8091 g Zn</em>
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