Explanation:
Yes, a chemical reaction can happen with only one substance.
A typical example of such reaction is the radioactive decay.
Radioactive decay is the loss of elementary particles from an unstable nucleus, ultimately changing the unstable element into another more stable element. .
When radioactive elements are let alone, they decompose to form stable harmless elements.
An example of radioactive decay is attached in the image below;
Environmental Chemistry studies the health hazards associated with lead, which is dangerous to humans.
Environmental Chemistry studies chemicals present in air, water and soil and their impact on humans and their environment.
Now, it was discovered that even low doses of lead particles in the paint when inhaled or ingested caused damaging effect to the body such as Impaired balance, seizures, ataxia and even death.
With the role of Environmental chemists in thier research and findings, the world has been informed on the negative effect on the expose of lead and other heavy metals like it to man and his environment.
See more here:brainly.com/question/22517940
The statement that correctly compares protons, electrons, and neutrons is, "Quarks are present in protons and neutrons but not in electrons". Quarks are tiny particles which compose the neutrons and protons. These quarks in protons and neutrons are linked together by gluons.
Answer:
20.19 amu.
Explanation:
From the question given above, the following data were obtained:
Isotope A:
Abundance (A%) = 90.5%
Mass of A = 20 amu
Isotope B:
Abundance (B%) = 9.5%
Mass of B = 22 amu
Average atomic mass =..?
The average atomic mass of the element can be obtained as follow:
Average atomic mass = [(Mass of A × A%)/100] + [(Mass of B × B%)/100]
Average atomic mass = [(20 × 90.5)/100] + [(22 × 9.5)/100]
Average atomic mass = 18.1 + 2.09
Average atomic mass = 20.19 amu
Therefore, the average atomic mass of the element is 20.19 amu
To Find :
How many moles are in 
atoms of iron.
Given :
We know, 1 mole of any element or compound contains exactly 
( Avogadro's Number ) atoms/compound .
Now, 
So, number of moles in given number of atoms are :
Hence, this is the required solution.
