B. Pandemic
C. Epidemiology
D. Toxicology
The answer is A
The bacteria that cause disease are known as pathogens. The term pathogen is used to refer to all types of disease causing microorganisms. These include bacteria, fungi, protozoa and fungi.
Bacteria. Microscopic organisms that come in many shapes and sizes. Some bacteria that cause disease in man are Salmonella typhi which causes typhoid and Streptococcus pyogens which causes sore throat.
Virus. A virus is a microscopic entity much smaller than even bacteria and can only exist inside a host such as a cell. It cannot live on its own. Some viruses that cause disease are HIV which causes AIDS and Rhino virus which causes colds.
Fungi. These are a group of unicellular or multicellular microscopic organisms that live by feeding on organic matter. A type of fungus that causes disease is Trichophyton mentagrophyte which is responsible for athlete's foot.
Protozoa. A group of one celled organisms which live in water. Entamoeba histolytica is a protozoa, an amoeba which causes amoebic dysentery in man.
According to the concept of Avogadro's number, there are 1.499 moles of hydrogen gas contained in 9.03 x 10²³ molecules.
Avogadro's number is defined as a proportionality factor which relates number of constituent particles with the amount of substance which is present in the sample.
It has a SI unit of reciprocal mole whose numeric value is expressed in reciprocal mole which is a dimensionless number and is called as Avogadro's constant.It relates the volume of a substance with it's average volume occupied by one of it's particles .
According to the definitions, Avogadro's number depend on determined value of mass of one atom of those elements.It bridges the gap between macroscopic and microscopic world by relating amount of substance with number of particles.
Number of atoms can be calculated using Avogadro's number as follows: mass/molar mass×Avogadro's number
Number of moles is calculated from Avogadro's number as, 1 mole=6.023×10²³ molecules , thus 9.03×10²³ molecules will have 9.03×10²³ /6.023×10²³=1.499 moles.
Thus, there are 1.499 moles of hydrogen gas contained in 9.03 x 10²³ molecules.
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Buffer capacity is defined as the capacity of a buffer to resist changes in pH upon addition of an acid or a base. The buffer capacity is high when the concentration of the acid and its conjugate base is high, and the pH of the solution is near the pKa value of the weak acid.
The greater the buffer capacity, the better it can resist pH changes upon addition of an acid or base. The buffer capacity of a solution is highest when the pH is near the pKa value of the weak acid.
A buffer is a solution that has the ability to resist changes in pH upon the addition of an acid or base. The buffer capacity is highest when the pH of the buffer is close to the pKa of the weak acid component in the buffer. Therefore, the buffer capacity is the highest when the pH is equal to the pKa value of the weak acid.
Therefore, the solution with the greatest buffer capacity is the one with the highest concentration of both the weak acid and its conjugate base, which can resist the changes in pH with the addition of an acid or base.
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By using flame test we can identify the elements because colors which are given by elements with flame test are unique.
During the flame test, the electrons of the atom which are in ground state absorb energy and go to upper level. This is called electron excitation. Excited electrons are unstable. Hence, they come back to the ground state by emitting the energy as photons.If that released energy has a frequency which belongs to visual light, then that wave gives a color.
The colors observed during a flame test are caused by the presence of certain metal ions. When these metal ions are heated by a flame, the electrons in their outer energy level get excited and move to higher energy levels. As they return to their original energy levels, they release energy in the form of light, which we perceive as different colors.
During a flame test, the colors observed are caused by the presence of certain metal ions. When these metal ions are heated by a flame, the electrons in their outer energy level get excited and move to higher energy levels. As they return to their original energy levels, they release energy in the form of light, which we perceive as different colors.
For example, when a copper compound is heated, it emits a green color. This is because copper ions are responsible for this color. Different metal ions will emit different colors, allowing us to identify them by their characteristic flame color.
Therefore, the colors observed during a flame test are a result of the specific metal ions present in the substance being tested.
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Davisson and Germer is not the correct answer, I just finished the test. The answer has to be Maxwell I hope this helps someone else fo sho
The work of Davisson and Germer helped to explain light's ability to propagate through a vacuum. They designed and built a vacuum apparatus for the purpose of measuring the energies of electrons scattered from a metal surface. Electrons from a heated filament were accelerated by a voltage and allowed to strike the surface of nickel metal. They observed that at certain angles, there was a peak in the intensity of the scatters electron beam. The peak indicated wave behavior for the electrons.