Origin Of Chemistry Flashcards
What are the Four Fundamental Forces?
Gravity
Electromagnetism
Strong Nuclear Force
Weak Nuclear Force
What happened one second after the Big Bang?
Forces explode outward, leading to expansion. Therefore a decrease in temperature.
What happened three minutes after the Big Bang?
Decrease in temperature means that molecules have less kinetic energy. It became low enough for protons and neutrons to hold together. Leading to Hydrogen atoms.
Is the fusion of H into He endothermic, or exothermic?
exothermic
What is the energy in exothermic reactions used for in the early universe.
To fuel further reactions.
What does the Strong Nuclear Force help overcome?
Electrostatic repulsion of protons.
Does H have neutrons.
Isotopes do, though generally H does not.
Does He have neutrons.
Yes.
Simplified reaction of H -> He:
4H -> He + ? + ?
4H -> He + 2 Positrons + Energy.
Where does fusion in Stars occur? Why?
Core. It’s the hottest, densest part.
What is the heaviest element that can be produced in the core of a Star.
Iron.
Where are the heaviest elements produced.
Supernovas.
Why is the Star’s core so dense.
Highest temperature and pressure. Fusion occurs there. So that is where heavier elements are found.
What is the first step in the formation of a star.
Gravity pulling matter together.
How hot does it have to be for fusion to take place.
~ ten million C
