The best way to prevent the corrosion of iron is to paint the exposed iron with protective paint, because that prevents water from rusting the iron.
<u>Answer:</u> The fraction of atom's mass contributed by nucleus is 0.99
<u>Explanation:</u>
Nucleons are defined as the sub-atomic particles which are present in the nucleus of an atom. Nucleons are protons and neutrons.
The isotopic symbol of Helium-4 atom is 
Number of electrons = 2
Number of protons = 2
Number of neutrons = 4 - 2 = 2
We are given:
Mass of He-4 atom = 
Mass of 1 electron = 
Calculating the mass contributed by the nucleus = 
Mass of the nucleus of He-4 atom = 
To calculate the fraction of atom's mass contributed by the nucleus, we use the equation:

Putting values in above equation, we get:

Hence, the fraction of atom's mass contributed by nucleus is 0.99
Answer:
carbon dioxide is added to the atmosphere naturally when organisms respire or decompose,
Explanation:
<span>Among the given choices, the third option is the only one which illustrates single replacement.
(3)H2SO4 + Mg --> H2 + MgSO4
A single replacement is also termed as single-displacement reaction, a reaction by which an element in a compound, displaces another element.
It can be illustrated this way:
X + Y-Z → X-Z + Y</span>
Answer:
Take 100 ml of a 18 molar solution. The total number of moles is (1 liter/1000 ml) 100 ml 18 moles is 1.8 moles.
1.5 moles in 1 liter so If 1.1 liters of water is added, the total volume is 1.2 liters and 1.8 moles are dissolves in it. 1.8 moles/ 1.2 liters is 1.5 moles per liter.