Answer:
isotopes of hydrogen are protium,deuterium and tritium
This is a simple algebraic problem, specifically for the mixture type of problem. Let x be the mass of 40% solution and y be the mass of 70% solution. The first equation would then be:
x + y = 20 --> eqn 1
The second equation would be the mass balance shown below:
(x)(0.40) + y(0.70) = 20(0.52) --> eqn 2
Rearranging eqn 1,
x = 20 - y
Substitute this to eqn 2:
(20 - y)(0.40) + y(0.70) = 20(0.52)
Solve for y,
y = 8 grams
Finally, solve for x.
x = 20 - 8 = 12 grams
<em>Therefore, Serena needs 12 grams of the 40% solution and 8 grams of the 70% solution.</em>
Now that we have a background in the Lewis electron dot structure we can use it to locate the the valence electrons of the center atom. The valence-shell electron-pair repulsion (VSEPR) theory states that electron pairs repel each other whether or not they are in bond pairs or in lone pairs. Thus, electron pairs will spread themselves as far from each other as possible to minimize repulsion. VSEPR focuses not only on electron pairs, but it also focus on electron groups as a whole. An electron group can be an electron pair, a lone pair, a single unpaired electron, a double bond or a triple bond on the center atom. Using the VSEPR theory, the electron bond pairs and lone pairs on the center atom will help us predict the shape of a molecule.
The shape of a molecule is determined by the location of the nuclei and its electrons. The electrons and the nuclei settle into positions that minimize repulsion and maximize attraction. Thus, the molecule's shape reflects its equilibrium state in which it has the lowest possible energy in the system. Although VSEPR theory predicts the distribution of the electrons, we have to take in consideration of the actual determinant of the molecular shape. We separate this into two categories, the electron-group geometry and the molecular geometry.
A mixture has lots of different elements that are not necessarily bonded to each other, like sea water has lots of dirt, animals, and plant parts in it. Compared to a solution (strictly salt and water, which bond and ionize with each other).
