<span>John Dalton introduced a theory proposing that elements vary because of the mass of their atoms.
He said in his theory that all matter is made up of indivisible blocks called atoms. He also stipulated in his theory that elements are identical thus, have different sizes and masses.
Dalton's theory was different from Niels Bohr who proposed a new atomic model which was also commonly known as the modern atomic theory. Bohr's theory says that atoms are arranged in circular orbits around the nucleus. He patterned his model as the solar system.
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Amu valie on the top and abundsnce percent in decimals on the bottom for each isotope
Answer:
(a) adding 0.050 mol of HCl
Explanation:
A buffer is defined as the mixture of a weak acid and its conjugate base -or vice versa-.
In the buffer:
1.0L × (0.10 mol / L) = 0.10 moles of HF -<em>Weak acid-</em>
1.0L × (0.050 mol / L) = 0.050 moles of NaF -<em>Conjugate base-</em>
-The weak acid reacts with bases as NaOH and the conjugate base reacts with acids as HCl-
Thus:
<em>(a) adding 0.050 mol of HCl:</em> The addition of 0.050moles of HCl produce the reaction of 0.050 moles of NaF producing HF. That means after the reaction, all NaF is consumed and you will have in solution just the weak acid <em>destroying the buffer</em>.
(b) adding 0.050 mol of NaOH: The NaOH reacts with HF producing more NaF. Would be consumed just 0.050 moles of HF -remaining 0.050 moles of HF-. Thus, the buffer <em>wouldn't be destroyed</em>.
(c) adding 0.050 mol of NaF: The addition of conjugate base <em>doesn't destroy the buffer</em>
Answer: a) 
b) 
c) 
d) 
Explanation:
General representation of an element is given as:_Z^A\textrm{X}
where,
Z represents Atomic number
A represents Mass number
X represents the symbol of an element
Mass number is defined as the sum of number of protons and neutrons that are present in an atom.
Mass number = Number of protons + Number of neutrons
In an atom, when neutrons or protons are lost or gains, it directly affects the mass number of an atom.
Atomic number is defined as the number of protons or number of electrons that are present in an atom.
It is characteristic of a particular element.
Atomic number = Number of electrons = Number of proton
a) Z 74, A 186: 
b) Z 80, A 201: 
c) Z 34, A 76: 
d) Z 94, A 239.: 
Answer:
True
Explanation:
The greenhouse effect is the process whereby there is radiation from a atmosphere planet and the planet increase the temperature of the planet's surface to a temperature above normal.In this process the Earth's atmosphere becomes thicker with the influence substances such as gases
and the radiation coming from the sun is trapped, then the Earth becomes warmer. Green house effect is seen in global warming.
Carbon neutral can be described as a process of removing huge amount of carbon dioxide from the atmosphere in order to achieve zero carbon neutrality.It is also reffered to as carbon neutrality, and this can be achieved by actions of organizations, businesses and individuals .
Carbon neutral can be achieved in two ways;
: 1.) Maintaining a balance between carbon dioxide emissions and carbon removal by means of the process called carbon offsetting
2 ) the process of removal of carbon dioxide from the atmosphere in order to balance up emissions in another place.
Carbon positive is crucial to increase the positive influence of our daily activities on climate change and our resources.
while reduce the negative effect of our activities and business on evironment.
Therefore, the practice of making operations "carbon neutral" is a way to offset whatever damage is being done to the environment due to greenhouse gas emissions by purchasing credits from "carbon-positive" projects to balance out emissions is true because the harmful gasses that is been released to the atmosphere is balance up by the carbon neutral process hence the reduction in green house effect.