Non metals and metollids in periodic tables are the same how this helps ;)
Answer is: the compound is B₂O₃.
ω(O) = 68.94% ÷ 100%.
ω(O) = 0.6894; percentage of oxygen in the compound.
ω(X) = 31.06% ÷ 100%.
ω(X) = 0.3106; percentage of unknown element in the compound.
If we take 69.7 grams of the compound:
M(compound) = 69.7 g/mol.
n(compound) = 69.7 g ÷ 69.7 g/mol.
n(compound) = 1 mol.
n(O) = (69.7 g · 0.6894) ÷ 16 g/mol.
n(O) = 3 mol.
M(compound) = n(O) · M(O) + n(X) · M(X).
n(X) = 1 mol ⇒ M(X) = 21.7 g/mol; there is no element with this molecular weight.
n(X) = 2 mol ⇒ M(X) = 10.85 g/mol; this element is boron (B).
Answer: The mole ratio of oxygen to pentane for the combustion of pentane is 8 : 1.
Explanation: The given reaction is a type of combustion reaction.
Combustion reaction is a reaction in which a hydrocarbon reacts with oxygen gas to produce water and carbon dioxide gas.
For the reaction of pentane with oxygen, the balanced equation would be:
In the reaction, 1 mole of 
reacts with 8 moles of 
gas.
Thus giving us the mole ratio as
Oxygen : Pentane = 8 : 1
E since its a physical model i.e. you can touch and feel the model :)
Answer: Absorption. The transfer of energy carried by light waves to particles of matter.
Explanation:
