4)
a) Natural selection will work negatively against rabbits that only eat berries as the drought is preventing berries from growing. It wont have any negative impact on rabbits that only eat grass as the grass is still surviving.
b) The statement ‘population has variations’ is backed up by the fact that the rabbits eat different things. They aren’t all the same. The statement ‘some variations are favorable’ is backed up by the fact that the rabbits that only eat grass are able to survive the drought. Their variation in eating grass instead of berries let’s them live. The statement ‘a population will change over time’ is backed up by the fact that the rabbits that only eat berries will die out. This will not only change the size of the population but going forward will create a population that has more rabbits that eat only grass on account of natural selection.
Googles Definition of Convection: <span>the movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, denser material to sink under the influence of gravity, which consequently results in transfer of heat.
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Answer:
- <u>Option b. Atom P has an estimated Zeff of 7 and is therefore to the right of Atom Q, which has a Zeff of 6.</u>
Explanation:
Please, find attached the figures of both atom Q and atom P corresponding to this question.
The <u>features of atom Q are</u>:
- Each <em>black sphere</em> represents an electron
- In total this atom has 8 electrons: 2 in the inner shell and 6 in the outermost shell.
- Since it is assumed that the atom is neutral, it has 8 protons: one positive charge of a proton balances one negative charge of an electron. Thus, the atomic number of this atom is 8.
- Since only two shells are ocuppied, you can assert that the atom belongs to the period 2 (which is confirmed looking into a periodic table with the atomic number 8).
- <em>Zeff </em>is the effective nuclear charge of the atom. It accounts for the net positive charge the valence electrons experience. And may, in a very roughly way, be estimated as the number of protons less the number of electrons in the inner shells. Thus, for this atom, an estimated Z eff = 8 - 2 = 6.
The <u>features of atom P</u> are:
- Again, each black sphere represents an electron
- In total this atom has 9 electrons: 2 in the inner shell and 7 in the outermost shell.
- Since it is assumed that the atom is neutral, it has 9 protons.
- The atomic number of this atom is 9.
- Using the same reasoning used for atom Q, this atom is also in the period 2.
- Estimated Z eff = 9 - 2 = 7.
Then, since atom P has a greater Z eff than atom Q (an estimated Zeff of 7 for atom P against an estimated Z eff of 6 for atom Q), and both atoms are in the same period, you can affirm that <em>atom P</em> has a greater atomic number and<em> is therefore to the right of atom Q</em>.
We will use this formlula: Mass in grams = Number of moles x Molecular mass of 1 mole.
Since, we know the avagadro number is 6.02 x 10²³, we only have two unknown values left which are the molecular mass of CH3OH and its mole.
Molecular Mass: C = 12, H= 1, O = 16, since we have C=12, H4 = 4, O = 16, we will add them up: 12 + 4 + 16 =32
We know that one mole of anything = 6.02 x 10²³.
So we will use this formula to find the mole of methanol: Number of moles = Number of molecules / Avagadro number
Number of moles of CH3OH = (9.79 x 10^24)/6.02 x 10²³) = 16.263 moles.
Now we know that the molecular mass = 32 and the mole is = 16.263.
Now we can find its mass by using this formula: <span>Mass in grams = Number of moles x Molecular mass of 1 mole.
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Mass in grams = 16.263 x 32 = 520g
Get a magnet in a bag (inside out) and move the magnet all over the sand/iron and you can collect all the iron and turn the bag right side out and zip up the bag. Now you have the sand and iron separated and it will be harder to accidentally mix them later.
