<span> E = h v where v = frequency h = plancks constant 6.626 * 10 - 34
4.8 * 6.626 = 31.8 </span>
Answer:
The two samples have identical properties because they are the samples of the same element. Intensive properties are properties of matter that do not change depending on the amount of matter. Luster, reactivity, and ductility are all intensive properties. That is why the two samples can be different sizes or shapes, but have identical properties.
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.
1 mole ------------ 6.02 x10²³ molecules
? mole ----------- 1.505 x10²³ molecules
1.505x10²³ / 6.02x10²³ => 0.25 moles
hope this helps!
