How many grams of lithium are present in 7.22 x 10²⁴ atoms of lithium? A)17.8
B)102
C)38.2
D)83.2

The reaction q+r2=r2q is found to be first order in r2 and

Which of these would be caused by a chemical change? a) the formation of lava. b) sedimantary rock layering over time. c) metamorphic rock forming from igneous. d) metamorphic rock eroding to form sedimentary rock.

Compare and contrast physical changes with chemical changes.