In chemistry and physics, a valence electron is an outer shell electron that is associated with an atom, and that can participate in the formation of a chemical bond if the outer shell is not closed; in a single covalent bond, both atoms in the bond contribute one valence electron in order to form a shared pair.
4Fe + 3O2 → 2Fe2O3 <or> The chemical formula for rust is Fe2O3. Rust is formed when iron reacts with oxygen in moist air. The following chemical equation represents the reaction: 4Fe + 3O2 → 2Fe2O3. Water is necessary for the oxidation reaction to occur and to facilitate transport of the electrons.
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Let the percentage of K-39 be x
then the percentage of K-40 is 100-(x+0.01)
We know that the net weight should be 39.5. Therefore we can say
(39*x+40*(100-(x+0.01))+38*0.01)/100=39.5
(since we are taking it in percent)
39*x+40*(100-(x+0.01))+38*0.01=3950
39x+4000-40x-0.4+0.38=3950
2x=49.98
x=24.99
=25 (approx)
Therefore K-39 is 25% in nature and K-40 is 75% in nature.
Hope this helps.
<u>Answer:</u> The final temperature of the copper is 95°C.
<u>Explanation:</u>
To calculate the final temperature for the given amount of heat absorbed, we use the equation:

Q = heat absorbed = +133 J (heat is added to the system)
m = mass of copper = 5.00 g
c = specific heat capacity of copper = 0.38 J/g ° C


Putting values in above equation, we get:

Hence, the final temperature of the copper is 95°C.
Answer:
A volcanic eruption occurs when molten rock, ash and steam pour through a vent in the earth's crust. Volcanoes are described as active (in eruption), dormant (not erupting at the present time), or extinct (having ceased eruption; no longer active).
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