Lecture 1 Flashcards
What is potential energy?
Energy possessed because of position, e.g. chemical, gravitational.
What is an element?
A substance that cannot be broken down into other substances via chemical reactions.
How many of the 92 natural elements are essential for life?
25.
Which 4 elements make up 96% of living matter?
H, N, C, O.
What 4 elements make up the majority of 4% of living matter?
P, S, Ca, K.
Name 2 other trace elements.
Fe, I.
Define an atom.
Smallest unit of matter which still retains the properties of that element.
Define an atom.
Smallest unit of matter which still retains the properties of that element.
Atomic mass is the sum of…?
Protons, neutrons and electrons (though only use the electrons in very accurate work, as their overall contribution is usually negligible).
What is an isotope?
Different number of neutrons, same number of protons
(AKA different mass number, same atomic number).
Chemistry IDENTICAL.
Which are more stable, filled or unfilled orbitals?
Filled.
What is a compound?
A substance consisting of two or more elements in a fixed ratio.
What are the two types of covalent bond?
Polar and non polar.
How do ionic bonds form?
When 2 atoms very different in attraction for valence electrons come together.
What do many ionic bonds form?
A crystal.
Order these bonds from strongest to weakest:
Covalent, hydrogen, ionic, van der waals.
Ionic (700kJ/mol).
Covalent (400kJ/mol).
Hydrogen (10kJ/mol).
Van der waals (0.5kJ/mol).
What are van der waals bonds?
Interactions between electron clouds.
