Calculate the number of aluminium ions present in 0.051 g of aluminium oxide. (Hint: The mass of an ion is the same as that of an atom of the same element. Atomic mass of Al = 27 u)
Molar mass of aluminium oxide Al203
= (2 x 27) + (3 x 16)
= 54 + 48 = 102 g.
Therefore, 102g of Al203 contains = 2 x 6.022 x 1023 aluminium ion
Therefore,0.051 of Al203 contains = (2 x 6.022x 1023)/102 x 0.051
= (12.044 x 1023 x 0.051)/102
= (0.614 x 1023)/102
= 0.006022 x 1023
= 6.022 x 1020 Al+3 ions.
[Extra information: Molar mass is defined as the mass of a substance for a given amount where the amount of the substance refers to the number of molecules or atoms or compounds present in one mole of a substance. The SI unit of the Molar mass of a substance is always calculated in g/mol.
The chemical formula of the compound is a symbolic representation of its composition, e.g., the chemical formula of sodium chloride is NaCl.
It indicates the elements that are present in the compound and the ratio of these elements in the compound.]
Related Articles
- Calculate the number of aluminium ions present in 0.051 g of aluminium oxide (Al2O3). (Atomic masses: Al = 27 u; O = 16 u)
- Calculate the formula masses of the following compounds :(i) Sodium oxide, Na2O(ii) Aluminium oxide, Al2O3(Given : Atomic masses : Na = 23 u ; O = 16 u ; Al = 27 u)
- The mass of one atom of an element X is 2.0 × 10–23 g.(i) Calculate the atomic mass of element X.(ii) What could element X be?
- The ion of an element has 3 positive charges. Mass number of the atom is 27 and the number of neutrons is 14. What is the number of electrons in the ion?13101416
- What is meant by atomic mass, gram atomic mass of an element? Why is the mass have different expressions i.e., ‘u’ and ‘g’?
- What is the mass of(a) 1 mole of nitrogen atoms?(b) 4 moles of aluminium atoms (Atomic mass of aluminium = 27)?(c) 10 moles of sodium sulphite (Na2S03)?
- What mass of nitrogen, N2, will contain the same number of molecules as 1.8 g of water, H2O? (Atomic masses : N = 14 u ; H = 1 u ; O = 16 u)
- Calculate the number of molecules present in a drop of chloroform (CHCl3) weighing 0.0239 g.(Atomic mass : C = 12 u ; H = 1 u ; Cl = 35.5 u)
- The ion of an element has 3 positive charges. The mass number of atom of this element is 27 and the number of neutrons is 14. What is the number of electrons in the ion?(a) 13 (b) 10 (c) 14 (d) 16
- Draw the atomic structure of(i) an atom with same number of sub-atomic particles, (ii) an atom with same number of electrons in L and M shell.
- (a) What is meant by (i) atomic number, and (ii) mass number, of an element? Explain with the help of an example.(b) What is the relation between the atomic number and mass number of an element?(c) If an element M has mass number 24 and atomic number 12, how many neutrons does its atom contain?
- Calculate(a) the mass of one atom of oxygen(b) the mass of one molecule of oxygen(c) the mass of one mole of oxygen gas(d) the mass of one ion of oxygen(e) the number of atoms in 1 mole of oxygen molecule
- Establish the relationship between atomic number, mass number, isotopes, isobars, and valency of an atom.
- What is the number of zinc atoms in a piece of zinc weighing 10 g? (Atomic mass of Zn = 65 u)
- An element has atomic number 13 and an atomic mass of 27.(a) How many electrons are there in each atom of the element?(b) How are these electrons distributed in the various energy levels?
Kickstart Your Career
Get certified by completing the course
Get Started