Neil Bohr is the scientist who invented a model of the atom that most closely resembles the modern electron cloud model.
An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.
The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.
Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.
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Answer:
Pangaea
Explanation:
a. True
b. False?
CO which is carbon monoxide is a primary pollutant for air pollution. As it contributes to the major proportion in the air pollutants amongst others. It has 48% percent of pollutants in comparison to other pollutants of air. The source of carbon monoxide is mainly from incomplete combustion of fuel mostly from the older cars.
The rise in atmospheric CO results in fatigue, drowsiness and my also sometimes lead to death of the person exposed to it.
The statement is true. Carbon monoxide (CO) is a primary pollutant, which is directly emitted into the environment from vehicles and machines burning fossil fuels and can negatively impact our health by limiting the oxygen transportation in the body.
Yes, the statement 'CO is a primary pollutant' is True. Primary pollutants are those that are directly emitted into the environment and have a damaging effect. Carbon monoxide (CO) is a significant primary pollutant that is largely produced by vehicles and other machines that burn fossil fuels. It is harmful because, when inhaled, CO can limit your body's ability to transport oxygen in your bloodstream, leading potentially to serious health problems.
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Answer: Option (c) is the correct answer.
Explanation:
Moh's scale is used to detect the harness of a mineral. This scale displays harness of 10 minerals.
According to Moh's scale, the hardness of minerals given in the option are as follows:
Graphite is not included in Moh's scale.
Thus, we can conclude that the hardest known mineral is diamond.
The correct answer for above statement:
chromium is in group 6 d-block
Explanation:
The d-block elements are designated transition metals and have valence electrons in d orbital's. The f-block elements, observed in the two rows at the ground of the periodic table, are called inner transition metals and have valence electrons in the f-orbital's.
Chromium is a synthetic element with symbol Cr and atomic number 24. It is the first component in group 6. It is a steely-gray, glistening, dense and brittle metal which takes a high polish, resists smudging, and has a great melting point.
2 moles
3 moles
6 moles
Answer:
Moles of gas added = 3 moles
Explanation:
Given:
Initial volume of gas, V1 = 2.0 L
Initial moles of gas, n1 = 3 moles
Final volume, V2 = 4.0 L
To determine:
The moles of gas added to bring the final volume to 4.0 L
Explanation:
Based on the ideal gas equation
where P = pressure, V = volume ; n = moles of gas
R = gas constant, T = temperature
At constant P and T, the above equation becomes:
V/n = constant
This is the Avogadro's law
Therefore:
The final number of moles of gas = 6
Thus, moles added = Final - Initial = n2 - n1 = 6-3 = 3 moles