MCQ 511 Mark
What is the formula mass unit of ZnO?
- A18u
- B81u
- C88u
- D188u
Answer
View full question & answer→- 81u
Explanation:
Elements X and Y, most likely, are nitrogen and iron.
Explanation:
Atoms and void are the bases of Democritus system for explaining the universe: solid indestructible atoms, infinite in number and shape, differing in size, but otherwise lacking in sensible qualities, were originally scattered throughout infinite void.
In general, the atoms were so small as to be invisible.
Atomos means that the atoms are physically indivisible.
Explanation:
The correct symbols of cobalt, aluminium, and sodium are Co, Al and Na respectively.
Explanation:
Cu is the symbol for copper. It is derived from the Latin name, Cuprum.
Explanation:
The symbol of the metal used in making thermometers is Hg(Mercury).
Explanation:
The symbol for SI unit of mole is mol.
It is not represented by mole.
M is the symbol for the molarity of the solution.
Explanation:
Molecular mass is the sum of masses of the atoms in the molecules.
Explanation:
Berzelius proposed the first letter (or first letter and another letter) of the Latin or English name of any element as its symbol.
Explanation:
The ratio of moles of atoms in 12g of Magnesium and 16g of Sulphur will be 1 : 1
Explanation:
The atomic number of element Y would be 12.
Explanation:
Avagadro's number is the number of units in one mole of any substance, equal to 6.023×1023.
The units may be electrons, ions or molecules depending on nature of the substance & character of the relation.
⇒ If one mole=[6.023×1023], then number of atoms is Avagadro's number.
Explanation:
Molar mass of Al2O3 = 2 × 27 + 3 × 16 = 54 + 48 = 102g
102g of Al2O3 contains = 2 × 6.22 × 1023 Al3+ ions
$\therefore$ 0.051g of Al2O3 contains $=\frac{2\times6.022\times10^{23}}{102}\times0.051$
= 6.022 × 1020 Al3+ ions.
Explanation:
Molecular weight is the mass of whole molecule.
Steps:- (1) Chemical formula of calcium carbonate ⟶CaCO3
(2) Mass of Calcium⟶ 40
Mass of Carbon⟶ 12
Mass of Oxygen⟶ 16
(3) Multiply mass of each element by number of atoms of that element.
(4) Add all the masses obtained after multiplication.
⟶CaCO3
= 1 × 40 + 1 × 12 + 3 × 16
= 40 + 12 + 48
= 100.
Explanation:
The atomic mass of an element is numerically equal to the mass of 1 mole of its atoms.
1 mole of atoms = 6.022 × 1023 atoms
Now, 1 atom of element X has mass = 2.65 × 10 - 23g
So, 6.022 × 1023 atoms of element X have mass = 2.65 × 1023 × 6.022 × 10
= 15.96 = 16g
Atomic mass of the element X is 16u.
Oxygen is the element with atomic mass 16 and having symbol O.
Explanation:
The law of constant proportion was proposed by Joseph Proust.
Explanation:
Out of ozone, phosphorus, sulphur and krypton, krypton has the lowest atomicity and sulphur the highest .
Explanation:
The law of conservation of mass was given by Lavoisier.
Explanation:
The English name of the element natrium is Sodium(Na).
Explanation:
Mass of Ca3(PO4)2
= (3 × atomic mass of Ca) + (2 × atomic mass of phosphorus) + (8 × atomic mass of oxygen)
=3 × 40 + 2 × 31 + 8 × 16 = 310
Explanation:
Formula of nitride of the element X will be XN.
Explanation:
Valencies of element X and Y will be 1 and 3, respectively.
Explanation:
The Latin name of the element potassium is kalium. Hence, the symbol for potassium is K.
Explanation:
Phosphorus has an atomicity of 4.
NA
Explanation:
Name "sodium" has been derived from Latin - natrium.
Explanation:
Name "sodium" has been derived from Latin - natrium.
Explanation:
The cation of an element has less electrons than a neutral atom.
Explanation:
Atoms of helium and neon exist in a free state because they are inert gases and chemically inactive.
Explanation:
The atomic theory of matter was proposed by John Dalton.
| Element | Symbol | Atomic number | Atomic radius in nanometers |
| Hydrogen | H | 1 | 0.037 |
| Helium | He | 2 | 0.05 |
| Lithium | Li | 3 | 0.152 |
| Beryllium | Be | 4 | 0.111 |
| Boron | B | 5 | 0.088 |
| Carbon | C | 6 | 0.077 |
| Nitrogen | N | 7 | 0.070 |
| Oxygen | O | 8 | 0.066 |
| Fluorine | F | 9 | 0.064 |
| Neon | Ne | 10 | 0.070 |
| Sodium | Na | 11 | 0.186 |
Explanation:
If the atomic number of X is 13, the number of electrons in its X3+ ion would be 13 - 3 = 10.
Explanation:
Element with an atomic number 16 will have 18 electrons in its E2- ion because anions are formed by gaining electrons.
Explanation:
The atomicity of ozone(O3) is 3, sulphur(S)- 8, phosphorus(P)- 4, Argon(noble gas, Ar)- 1.
Explanation:
The anion of an element has more electrons than the normal atom because it is formed by gaining electrons.
Explanation:
CaCl2 is made up of two ions, The cation is Ca2+ and the anion is Cl−
Explanation:
Formula unit mass is known as sum of atomic masses of all atoms in a formula unit of an ionic compound.
Explanation:
Because 20 miles of water is 360g and also number of particles in 360g of water is 1.2044 x 1025
Explanation:
20 moles of water and 1.2044 × 1025 molecules of water correctly represent 360gms of water.
Explanation:
Smallest possible unit of a compound which has independent existence is a molecule.
A molecule is the smallest particle in a chemical element or compound that has the chemical properties of that element or compound.
Molecule are made up of atoms that are held together by chemical bonds.
These bonds form as a result of the sharing or exchange of electrons among atoms.
Explanation:
Smallest particle of an element or a compound which is capable of independent existence is called molecule.A molecule is formed when two or more atoms join together chemically.
Molecules of elements like noble gases such as helium,neon etc are made up of one atom only(molecules are capable of independent existence while atoms are not capable of independent existence).
Only in these case atoms are capable of independent existence.
Noble gases are monoatomic.