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).
In redox reactions, there is no net loss or gain of electrons, so the answer is (1) equal to the total number of electrons gained
Answer:
nooo all cells are not same
Explanation:
like heart cell, muscles cell
<span>A. smog
B. Use a large amount of water
C. increased temperatures
D. poisoning wildlife
The correct answer is D) poising wildlife. Burning fossil fuels and pesticide from farming have the effect of releasing toxic elements in nature, thus the consequences of poisoning wildlife. The fossil fuels released CO2 and other particulates that threats the respiration system of most animals, while the pesticide that animals ingest or breath can have different effects on the wildlife, depending on the type of pesticide.
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Explanation:
Noble gas configuration is defined as the configuration which contains completely filled orbitals.
For example, oxygen atom when gain two electrons then it forms oxygen ion (
).
Atomic number of oxygen atom is 8 and so, its number of electrons will also be 8. But when it gain two electrons then it has total 10 electrons. Hence, electronic configuration of
is as follows.

Since, there are completely filled orbitals in an
ions. Therefore, it means this ion has a noble-gas configuration.
Thus, we can conclude that any specie which shows completely filled orbitals will have noble-gas configuration.