Answer:
John Dalton:
John Dalton was the scientist who introduced atomic theory in the field of chemistry. Dalton worked on different gases and formulated this theory. The main points of Dalton's theory are:
- Every element present is made up of atoms.
- Atoms of an elements are have the same same properties whereas these properties are different for each element.
- According to his theory, an atom could not be broken down.
- Different atoms combine or get separated from each other during a chemical reaction.
Ernest Rutherford:
Ernest Rutherford is known as the father of nuclear physics due to his impressing research work on radioactivity of atoms. Rutherford was the first scientist to discover the nucleus of an atom and prove that the nucleus was charged. He also described that the electrons circle around the nucleus of an atom.
Answer:
we will use the Clausius-Clapeyron equation to estimate the vapour pressures of the boiling ethanol at sea level pressure of 760mmHg:
ln (P2/P1) =
-
)
where
P1 and P2 are the vapour pressures at temperatures T1 and T2
Δ
vapH = the enthalpy of vaporization of the ETHANOL
R = the Universal Gas Constant
In this problem,
P
1
=
100 mmHg
; T
1
=
34.7 °C
=
307.07 K
P
2
=
760mmHg
T
2
=T⁻²=?
Δ
vap
H
=
38.6 kJ/mol
R
=
0.008314 kJ⋅K
-1
mol
-1
ln
(
760/10)=(0.00325 - T⁻²) (38.6kJ⋅mol-1
/0.008314
)
0.0004368=(0.00325 - T⁻²)
T⁻²=0.002813
T² = 355.47K
If the units for gases were the same as the units for numbers would be too small to be convenient.
For example, the density of iron is 7.87 g/cm³.
Using the same units, the density of hydrogen is 0.000 0899 g/cm³.
It is much more convenient to express the density in numbers that are easier to visualize: 0.0899 g/L, and that is still a small number.
Answer:
pH = 7.46
Explanation:
2H₂O ⇄ H₃O⁺ . OH⁻ Kw = [H₃O⁺] . [OH⁻]
[H₃O⁺] = [OH⁻]
√0.12×10⁻¹⁴ = [H₃O⁺] → 3.46×10⁻⁸ M
- log [H₃O⁺] = pH
- log 3.46×10⁻⁸ = pH → 7.46