50 questions · timed · auto-graded
Dalton Atomic theory postulates-
All matter is made up of atoms and atoms are indestructible cannot be created or destroyed so the total mass of reactants remains equal to the total mass of products.
Phosphorus has an atomicity of $4.$
Avogadro number is the number of atoms in exactly $12 g$ of carbon $-12$ .
It is equal to $6.022 \times 10^{23}$.
Molar mass of $S _8=256 g mol ^{-1}$
We know,
$1$ mole of $S _8=$ Molar mass of $S _8=6.022 \times 10^{23}$ molecules.
$256 g$ of $S_8=6.022 \times 10^{23}$ molecules.
Hence, $16$ g of $S _8=\frac{6.022 \times 10^{23 \times} 16}{256}$ molecules
$=3.76 \times 1022$ molecules
$=3.76 \times 10^{22}$ molecules
$=3.78 \times 10^{23}$ molecules (approx)
$K, Na, Cu$ is derived from Latin names namely Kalium, Natrium, and Cuprum.
The symbol of Zinc is not taken from Latin names.
The electronic configuration of $2,6$ will accept two electrons to become an anion or negatively charged ion.
For all the other configurations, losing electrons would lead to a more stable state and would form cations instead.
Dalton believed matter to be made up of tiny indivisible particles called atoms.
Both Thomson and Rutherford considered the presence of charged species in an atom and did not believe in the indivisibility of atom.
|
S.No
|
Column I
|
|
Column II
|
|
$a$
|
$9.033 \times 10^{24}$ atoms
|
$i$
|
$46g$ of He
|
|
$b$
|
$2$ moles of Na
|
$ii$
|
$15$ moles
|
|
$c$
|
$11.2 L of O_2$ at $STP$
|
$iii$
|
$3.011 \times 10^{23}$ molecules
|
|
$d$
|
$22g$ of $CO_2$
|
$iv$
|
$16g$
|
|
S.No
|
Column I
|
|
Column II
|
|
$a$
|
$9.033 \times 10^{24}$ atoms
|
$ii$
|
$15$ moles
|
|
$b$
|
$2$ moles of Na
|
$i$
|
$46g$ of he |
|
$c$
|
$11.2 L of O_2$ at $STP$
|
$iv$
|
$16g$
|
|
$d$
|
$22g$ of $CO_2$ |
$iii$
|
$3.011 \times 10^{23}$ molecules |
Sulphur exhibits the valencies of $2, 4$ and $6.$
A substance consisting of atoms or ions of two or more different elements in definite proportions joined by chemical bonds into a molecule is known as compound.
The elements cannot be separated by physical means.
Water, for example, is a compound having two hydrogen atoms and one oxygen atom per molecule.
Molecular mass is expressed in $'u'$, or unified atomic mass unit.
Molar mass of Hydrochloric acid $= 1 \times $ atomic mass of $H + 1 \times $ atomic mass of $Cl$
$= 1 \times (1) + 1 \times (35.5)$
$= 36.5u$
| Elperiment number | Mass of $H_2$ reacted | Mass of $o_2$ reacted | Mass of $H_2O$ produced |
| $1$ | $2g$ | $16g$ | $18g$ |
| $2$ | $4g$ | $32g$ | $36g$ |
| $3$ | - | - | $9g$ |