Functional groups create reactive sites in molecules.
The polar part of a molecule that can hydrogen bond to water is said be hydrophilic.
Pi (π) bonds create active sites and will react with electron-deficient species.
A electronegative heteroatom like nitrogen, oxygen, or a halogen makes a carbon atom electrophilic.
(carbon will have less electronic density, which is attracted by the more electronegative heretoatoms, and it will tend to attract electron rich chemical species, and in this situation we say that the carbon atom is electrophilic).
The nonpolar part of a molecule that is not attracted to water is said to be hydrophobic.
A lone pair on a heteroatom makes it basic and nucleophilic.
(the heteroatom with the lone pair will tend to attract electron poor chemical species, and in this situation we say that the heteroatom is nucleophilic).
Answer:
Velocity = 22.11 m/s
Explanation:
Using the equation;
λ = h / mv;
where
λ = wavelength ( 3.46 x 10^-33 )
m = mass of the marble ( 8.66 g )
v = velocity ( we gotta find out )
h = planck's constant ( 6.626 * 10^-34 )
Making v the subject of the formula;
V = h /mλ
=(6.626 x 10^-34 ) / 0.00866 ( 3.46 x 10^-33 )
= 22.1135
≈ 22.11 m/s
Nitrate ions 
and potassium ions 
.
<h3>Explanation</h3>
Potassium dichromate undergoes a double-decomposition reaction with barium nitrate to produce barium dichromate and potassium nitrate. The reaction is possible due to the low solubility of barium dichromate that precipitate out of the solution readily after its production.
Start with the balanced chemical equation for this process:
Rewrite the chemical equation as an ionic one; express all soluble salts- those with state symbol (aq)- as their constituting ions while leaving the insoluble (s) intact.
and 
are found on both sides of the equation by the same quantity. The two ions thus took no part in the net reaction and act as spectator ions.
