Concepts for Day 1 Flashcards
from ChE Books
An unstable nucleus exhibits ___
radioactivity
nucleus contains essentially all the atom’s mass but
is only about ___
10^-5 its radius
identical to helium-4 nuclei
alpha particles
very high-energy photons
Gamma rays
high-speed electrons
Beta particles
one disintegration per
second (d/s)
becquerel (Bq)
number of disintegrations per
second in 1 g of radium-226
1 Ci = 3.7x10^10 d/s
proposed the technique of radiocarbon dating
Willard F. Libby
equal to 1 joule of energy absorbed per kilogram of
body tissue
gray (Gy)
discovered biochemical pathway using 14C in CO2
Melvin Calvin
substance that cannot be separated into simpler substances by chemical means
element
Molecules in a ___ are close together but are not held so rigidly in position and can move past one another.
liquid
It is the lowest temperature that can be attained theoretically
0 K
___ tells us how close a measurement is to the true value of the quantity that was measured
Accuracy
Precision
refers to how closely two or more measurements of the same quantity agree with one another
_____ the lightest elements that were the first elements formed in the early stages of cosmic evolution.
helium and hydrogen