Answer:
1.35 moles of O²⁻
21.6 grams of O²⁻
Explanation:
We know that the charge on Aluminium ion is +3 (i.e. Al³⁺) while, the charge on Oxide ion is -2 (i.e. O²⁻). Therefore, the overall neutral Al₂O₃ compound has 2 Al³⁺ ions and 3 O²⁻ ions. Since, we can say that,
1 mole of Al₂O3 contains = 3 moles of O²⁻ ions
So,
0.450 moles of Al₂O₃ will have = X g of O²⁻
Solving for X,
X = 0.450 mol × 3 mol ÷ 1 mol
X = 1.35 moles of O²⁻
As the mass of an atom is mainly due to the presence of protons and neutrons hence, the addition of two electrons (-ve 2 shows two gained electron) to Oxygen will make a negligible change to the atomic masss of Oxygen because electron is said to be almost 1800 times lighter than proton. Hence, the ionic mass of O²⁻ will be 16 g/mol and the mass of given moles is calculated as,
Mass = Moles × Ionic Mass
Mass = 1.35 mol × 16 g/mol
Mass = 21.6 g
Nice written.
Is it written by you yourself or you have copied it from somewhere?
Answer:
sorry
Explanation:
i'm not a chemistry student
but let me try
it is because the neutron of an atom is -
why the proton and electron is +and- (positive and negative)
so + and - = 0
The molar mass of sodium is 22.99 ㅤ ㅤ ㅤ 22.99 (28) = 643.72 mol now multiply by avogrados number to find the number of atoms. ㅤ ㅤ ㅤ 643.72 (6.022 x 10^23) = 3.88 x 10^26 number of atoms
