A classic example of natural selection is the origin of giraffes long necks. The ancestors of modern giraffes were similar to deer with necks of ordinary length. Here natural selection accomplish Darwin's idea of "survival of the fittest". The correct option is A.
The mechanism through which living creature populations adapt and change is defined as the natural selection. The genes which are responsible for the survival of an organism are passed on to the successive generations.
Natural selection states that the organisms which are able to survive and reproduce with the changing environmental conditions are selected by the nature whereas the ones which cannot survive are eliminated.
So the survival of fittest means that the organisms which are suited to the environment will survive. Survival of the fittest is an expression developed from Darwin's theory of evolution.
Thus the correct option is A.
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The mole concept can be used to determine the number of ozone molecules are lost in the atmosphere.
The mole concept was introduced by Avogadro. The mole is the SI unit of amount of substance. According to Avogadro, one mole of a substance contains 6.02 × 10^23 atoms, ions, molecules etc. The mole concept is important in many chemical calculations. The quantity amount of substance is a measure of how many elementary entities of a given substance are in an object or sample.
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Answer:
determining how many ozone molecules are lost in the atmosphere
obelium (No, 102) – Alfred Nobelroentgenium (Rg, 111) – Wilhelm Roentgen (formerly Ununumium)rutherfordium (Rf, 104) – Ernest Rutherford seaborgium (Sg, 106) – Glenn T. Seaborg
B. It helps create new colors of light in the visible spectrum.
C. It helps compare the applications of electromagnetic waves.
D. The wavelength of light waves can be changed using the model.
b. A 100.0 g sample of liquid ethanol vaporizes at its boiling point. Hvap = 38.6 kJ/mol
The heat required for the following two processes are:
a. 10.74 KJ
b. 83.92 KJ
Part a)
Given:
Mass (m) of ethanol = 100g
Heat of fusion, Hfus = 4.94 kJ/mol
To find:
Heat (Q) =?
Mass of C₂H₅OH = 100g
Molar mass of C₂H₅OH = (2x12)+ (5x1) + 16 + 1 = 46g/mol
Number of Mole = Mass /Molar Mass
Number of mole (n) of C₂H₅OH = 100/46 = 2.174 moles.
Calculation for Heat of fusion:
Q = n x Hfus
Q = 2.174 mol x 4.94 kJ/mol
Q = 10.74KJ
Therefore, 10.74 KJ of heat is required to melt the ethanol.
Part b)
Given:
Mass of C₂H₅OH = 100g
Heat of vaporization, Hvap = 38.6 kJ/mol
To find:
Heat (Q) =?
Calculation for Heat of vaporization:
As calculated above, the number of mole in 100g of ethanol, C₂H₅OH is 2.174 moles.
The heat required to vaporize the ethanol can be obtained as follow:
Q = n x Hvap
Q = 2.174 mol x 38.6 kJ/mol
Q = 83.92 KJ
Therefore, 83.92 KJ of heat is required to vaporize the ethanol.
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Answer:
A. 10.74 KJ
B. 83.92 KJ
Explanation:
A. Data obtained from the question include the following:
Mass (m) of ethanol = 100g
Heat of fusion, Hfus = 4.94 kJ/mol
Heat (Q) =..?
Next, we shall determine the number of mole in 100g of ethanol, C2H5OH. This is illustrated below:
Mass of C2H5OH = 100g
Molar mass of C2H5OH = (2x12)+ (5x1) + 16 + 1 = 46g/mol
Number of mole (n) of C2H5OH =..?
Mole = Mass /Molar Mass
Number of mole (n) of C2H5OH = 100/46 = 2.174 moles.
Now, we can obtain the heat required to melt the ethanol as follow:
Q = n x Hfus
Q = 2.174 mol x 4.94 kJ/mol
Q = 10.74KJ
Therefore, 10.74 KJ of heat is required to melt the ethanol.
B. Data obtained from the question include the following:
Mass of C2H5OH = 100g
Heat of vaporisation, Hvap = 38.6 kJ/mol
Heat (Q) =..?
As calculated above, the number of mole in 100g of ethanol, C2H5OH is 2.174 moles.
The heat required to vaporise the ethanol can be obtained as follow:
Q = n x Hvap
Q = 2.174 mol x 38.6 kJ/mol
Q = 83.92 KJ
Therefore, 83.92 KJ of heat is required to vaporise the ethanol.
C. From the above calculations, a higher amount of heat energy i.e 83.92 KJ is required to vaporise the ethanol and a lesser amount of heat energy i.e 10.74 KJ is needed to melt the ethanol.
The energy levels of an atom are occupied by electrons. These energy levels are often represented as shells, and each level can hold a specific number of electrons. Electrons are crucial in determining an atom's properties.
The energy levels of an atom are occupied by electrons. An atom's structure consists of a nucleus, which is surrounded by the energy levels. These energy levels, often represented as shells, house the electrons. For example, the first energy level can accommodate up to 2 electrons, while the second energy level can hold up to 8. These electrons play a critical role in determining the physical and chemical properties of atoms and subsequently, the substances they form.
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