unit 1 - chapter 2 (chemical context of life) Flashcards
what is matter conceptually?
substance, takes up spaces, has mass, can exist as solid/liquid/gas, comprised of elements
what is matter chemically?
consists of chemical elements in pure form and in combinations called compounds
what is an element?
substance which cannot be broken down by chemical means
what is a compound?
substance of 2 or more elements in a fixed ratio
what is an atom?
“uncuttable” thing
what is a nucleus?
central part of atom
what is a proton?
positive charge nuclear particle
what is an electron?
negative charge atomic particle
what is a neutron?
no charge nuclear particle
what is an amu also equivalent to?
a dalton
how much smaller is an electron than a proton or neutron?
electron is 1/2000 the mass of a proton or neutron
what is an isotope?
same element, same # of protons, different # of neutrons, different mass
what happens to unstable isotopes?
they will decay or lose particles and release energy and eventually cause radiation
what is radioactivity measured with?
a Geiger center
what is radioactivity used for?
used as tracers and used to date
is the nuclei directly involved in chemical processes?
no
what is energy?
the capacity to do work or effect change, it comes in many forms
what is potential energy?
energy of position or structure
how are molecules formed?
through chemical bonds
how do strong chemical bonds form?
they form bc atoms are more stable when their valence shells are filled
what are the 2 stronger bonds?
intramolecular bonds; covalent and ionic
what are the 2 weaker bonds?
intermolecular bonds; hydrogen bonds and Van der Waals interactions
what is a covalent bond?
2 atoms share a pair of electrons and this completes both of their valence shells
what is a polar covalent bond?
the uneven sharing of electrons
what is an ionic bond?
1 atom “gives” valence electron to another atom to complete valence shell
what is an ion?
charged atoms or molecules where the number of protons doesn’t equal the number of electrons
what is a positively charged ion called?
cation
what is a cation?
a positively charged ion
what is a negatively charged ion called?
anion
what is an anion?
a negatively charged ion
what affects ion bond strength?
environment
what do bonds contribute to molecules?
the shape, shape is essential to function
what do chemical reactions do to bonds?
they make or break them
in what types of molecules does van der waals attraction happen?
non-polar molecules
what is weaker, van der waals attraction or hydrogen bonds?
van der waals attraction
what is van der waals attraction?
asymmetry in charge distribution
