Empirical formula of caffeine is C₈H₁₀N₄O₂.
In 1 mol of caffeine we have 10 mol of hydrogen.
In 2,8 mol of caffeine we have x mol of hydrogen.
x = 2,8 mol * 10 mol / 1 mol = 28 mol
ANSWER: There are 28 mol of hydrogen.
:-) ;-)
<em>Calculate the pH of the following substances formed during a volcanic eruption:
</em>
<em>• Acid rain if the [H +] is 1.9 x 10-5
</em>
<em>• Sulfurous acid if [H +] = 0.10
</em>
<em>• Nitric acid if [H +] = 0.11</em>
<em />
<h3>Further explanation </h3>
pH is the degree of acidity of a solution that depends on the concentration of H⁺ ions. The greater the value the more acidic the solution and the smaller the pH.
pH = - log [H⁺]
![\tt pH=-log[1.9\times 10^{-5}]\\\\pH=5-log1.9\\\\pH=4.72](https://tex.z-dn.net/?f=%5Ctt%20pH%3D-log%5B1.9%5Ctimes%2010%5E%7B-5%7D%5D%5C%5C%5C%5CpH%3D5-log1.9%5C%5C%5C%5CpH%3D4.72)
![\tt pH=-log[10^{-1}]\\\\pH=1](https://tex.z-dn.net/?f=%5Ctt%20pH%3D-log%5B10%5E%7B-1%7D%5D%5C%5C%5C%5CpH%3D1)
![\tt pH=-log[11\times 10^{-2}]\\\\pH=2-log~11=0.959](https://tex.z-dn.net/?f=%5Ctt%20pH%3D-log%5B11%5Ctimes%2010%5E%7B-2%7D%5D%5C%5C%5C%5CpH%3D2-log~11%3D0.959)
Answer:
See explanation
Explanation:
The central atom in the perbromate ion is bromine. The chemical symbol of bromine is Br. There are no lone pairs around the central bromine atom. The ion is tetrahedral in shape hence we expect a bond angle of 109°. 27 which is the ideal tetrahedral bond angle. The actual bond angle of the prebromate ion is 109.5°. The perbromate ion is BrO4^-
The observed bond angle is very close to the ideal value because of the absence of lone pairs of electrons from the central atom in the ion.
1. The answer is option E, that is None of the above is correct.
As a polymer becomes more crystalline,
its melting point doesn't decreases, its density doesn't decreases, its stiffness doesn't decreases and its yield stress doesn't decreases.
2. The answer is option B, that is the molecules are arranged in sheets, with their long axes parallel and their ends aligned as well.
In the smectic A liquid-crystalline phase, molecules are arranged in sheets, with their long axes parallel and their ends aligned as well.
3. For a substitutional alloy to form, the two metals combined must have similar atomic radii and chemical bonding properties.
Answer:
Bottom line: A redshift reveals how an object in space (star/planet/galaxy) is moving compared to us. It lets astronomers measure a distance for the most distant (and therefore oldest) objects in our universe.
Explanation:
A redshift reveals how an object is moving in space and enables astronomers to discover otherwise-invisible planets and the movements of galaxies, and to uncover the beginnings of our universe.
They use a property called a "redshift" to describe the motion of an objects moving away from each other in space. Redshift occurs when an object emitting electromagnetic radiation recedes from an observer. The light detected appears "redder" than it should be because it is shifted toward the "red" end of the spectrum.Because the location of spectral features usually shifts to longer wavelengths -- towards the red end of the spectrum -- astronomers refer to this as the redshift of a galaxy. Take a look for yourself at the appearance of some very distant, very fast-moving galaxies in the Hubble Ultra-Deep Field .
hoped this helped a brainlist would be nice :)
