Answer:
Here's what I get.
Explanation:
Quinine contains phosphors, substances that glow when they are hit with certain wavelengths of light.
The phosphors in quinine absorb UV light, which is invisible to our eyes.
Electrons in the phosphors absorb the UV energy and are excited to higher energy levels.
When the electrons drop back to lower energy levels, they emit some of this energy as a glowing blue visible light.
In a double-replacement reaction, the _____.?
There are many more interesting things to ask about double replacement reactions than are contained in the list given here. But the only correct choice is:
C.reactants are two ionic compounds
Answer:
Explanation:
Given parameters:
Mass of aluminium oxide = 3.87g
Mass of water = 5.67g
Unknown:
Limiting reactant = ?
Solution:
The limiting reactant is the reactant in short supply in a chemical reaction. We need to first write the chemical equation and convert the masses given to the number of moles.
Using the number of moles, we can ascertain the limiting reactants;
Al₂O₃ + 3H₂O → 2Al(OH)₃
Number of moles;
Number of moles = 
molar mass of Al₂O₃ = (2x27) + 3(16) = 102g/mole
number of moles =
= 0.04mole
molar mass of H₂O = 2(1) + 16 = 18g/mole
number of moles =
= 0.32mole
From the reaction equation;
1 mole of Al₂O₃ reacted with 3 moles of H₂O
0.04 mole of Al₂O₃ will react with 3 x 0.04 mole = 0.12 mole of H₂O
But we were given 0.32 mole of H₂O and this is in excess of amount required.
This shows that Al₂O₃ is the limiting reactant