An extinction event is a widespread and rapid decrease in the biodiversity on Earth. Such an event is identified by a sharp change in the diversity and abundance of multicellular organisms. It occurs when the rate of extinction increases with respect to the rate of speciation. -Wikipedia
Answer:
14
Explanation:
Given parameters:
Number of protons = 6
Number of electrons = 6
Number of neutrons = 8
Unknown:
Mass number = ?
Solution:
The mass number of an atom is the sum of protons and neutrons in an atom;
Mass number = number of protons + number of neutrons
Mass number = 6 + 8 = 14
The heat of a chemical reaction (change of enthalý) may be calcualted as the heat of formation of the products less the heat of formation of the reactants.
Then, for the given equation, the total heat of the combustion of pentnae is:
<span>ΔH°f = 5* ΔH°f CO2(g) + 6ΔH°f H2O(g) - ΔH°f C5H12(g) - 8ΔH°f O2(g)
</span>The standard heat of formation of O2(g) is zero because that is its natural state.
Now you can replace in the equation the values given:
<span>ΔH° = 5*(-393.5 kJ/mol) + 6*(-241.8kj/mol) - (-35.1kJ/mol) - 0
ΔH° = -3,383.2 kJ/mol
</span>
Then, the heat of the combustion of pentane is -3,383.2 kj/mol
It is important to conserve non renewable sources of energy such as coal and oil because they are running out. If we burn all the oil to generate electricity then there will be none left for other useful things we use oil for.
Titration experiments require the use of a burette. It is a long graduated glass tube held in place by a clamp stand. It has a tap fixture on the end that regulates the delivery of small volumes of liquid into a beaker in the titration process. Bunsen burners are used to heat substances and crucibles are used to hold items to be heated to high temperatures.