Answer is: 230 g.
Chemical reaction: P₄ + 5O₂ → 2P₂O₅.
m(P₄) = 100 g.
M(P₄) = 4 · 31 g/mol = 124 g/mol.
n(P₄) = m(P₄) ÷ M(P₄) = 100g ÷ 124g/mol = 0,806 mol.
From reaction: n(P₄) : n(P₂O5) = 1 : 2.
n(P₂O₅) = 1,612 mol.
m(P₂O₅) = 1,612 mol · 142g/mol = 230g.
M - molar mass.
n - amount of substance.
739 is the number of atoms of O in 92.3 moles of Cr3(PO4)2.
Explanation:
Molecular formula given is = Cr3(PO4)2
number of moles of the compound is 92.3 moles
number of 0 atoms in 92.3 moles =?
From the chemical formula 1 mole of the compound has 8 atoms of oxygen
So, it can be written as
1 mole Cr3(PO4)2 has 8 atoms of oxygen
92.3 moles of Cr3(PO4)2 has x atoms of oxygen
= 
x = 8 x 92.3
x = 738.4 atoms
There will be 739 oxygen atoms in the 92.3 moles of Cr3(PO4)2.
Answer:
They all have: nitrogen :780,900 755,100
oxygen: 209,500 231,500
argon 9,300 12,800
carbon dioxide
386 591
Double replacement is happening
Answer:
- The standard form of a chemical element is the natural mixture of several isotopes of the same element, which is atoms with the same number of protons but different number of neutrons, while an isotope is a particular kind of atom with a definite number of neutrons.
Explanation:
A <em>chemical element</em> is a pure substance formed by atoms with the same atomic number (number of protons). This is because it is the number of protons what identifies an element.
For example: oxygen is a chemical element, so oxygen is formed by only atoms of oxygen, and the atomic number of those atoms is 8, because every oxygen atom has 8 protons.
Nevertheless, some atoms of oxygen, may have different number of neutrons. Isotopes are different kind of atoms of the same element, which only differ in the number of neutrons. So, some atoms of oxygen will have 8 neutrons, other 9 neutrons, and other 10 neutrons (those are the stable isotopes of oxygen).
That difference in neutrons, is generally accepted that, does not modifiy substantially the chemical properties of the element, but the mass number. So, the isotopes with more neutrons wil be heavier, and the isotopes with less neutrons will be lighter.
- Mass number = number of protons + number of neutrons.
In general a chemical element is formed by a mixutre of isotopes of the same element.
