Answer:
Total mass of the reactant = 2+2.5 =4.5 mg
Total mass of product = 4.15 mg
therefore, mass of unreacted oxygen = 4.50-4.15 = 0.35 g
Noble gases already have eight electrons in their outer shells and they don't want to attract anymore. Since electronegativity measures the amount of attraction between an atom and an electron, noble gases do not have electronegativity.
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Answer:

Explanation:
The correct answer of this questions is 38°c
Answer:
0.34 M
Explanation:
I assume that the compound is PbCl2.
One mole of PbCl2 contains one mol of Pb+2 and 2 moles of Cl-
Molarity (M)= moles (n) /Volume (V)
Moles Pb2+ = M x V = 0.17 V
Moles Cl- = moles Pb2+ x (2 moles Cl-/1 mole Pb2+) = 0.17 V x 2 = 0.34 V
M Cl- = moles Cl-/V = 0.34V/V = 0.34 M