Assume that the rate law for a generic chemical reaction is rate = [a][b]3 . what is the reaction order in a, the reaction order in b, and the overall reaction order?

If the reaction is
     X + Y → Products

Then the rate is
     R = k[X]ᵃ [Y]ᵇ

Where,
R = the rate of the reaction (mol L⁻¹ s⁻¹)
k = rate constant
[X] and [Y] = concentrations of the reactants (mol L⁻¹)
a = order of the reaction with respect to X
b = order of the reaction with respect to Y
overall reaction order, n = a + b

according to the given rate expression,
rate = [a][b]³

order of the reaction with respect to 'a' is 1
order of the reaction with respect to 'b' is 3

Overall reaction order = 1 + 3
                                       = 4

The density of water is 1 g/cm cubed and in order for the pebble to sink its density has to be greater than the density of water and in order for the twig to float its density has to be less than the density of water

In any atom of any element, you will find protons and neutrons in the nucleus of any atom