<h3>
Answer:</h3>
0.699 mole CaCl₂
<h3>
Explanation:</h3>
To get the number of moles we use the Avogadro's number.
Avogadro's number is 6.022 x 10^23.
But, 1 mole of a compound contains 6.022 x 10^23 molecules
In this case;
we are given 4.21 × 10^23 molecules of CaCl₂
Therefore, to get the number of moles
Moles = Number of molecules ÷ Avogadro's constant
= 4.21 × 10^23 molecules ÷ 6.022 x 10^23 molecules/mole
= 0.699 mole CaCl₂
Hence, the number of moles is 0.699 mole of CaCl₂
To determine the number of gas particles in the vessel we add all of the components of the gas. For this, we need to convert the mass to moles by the molar mass. Then, from moles to molecules by the avogadro's number.
1.50x10^-6 ( 1 / 28.01) (6.022x10^23) = 3.22x10^16 molecules CO
6.80x10^-6 ( 1 / 2.02) (6.022x10^23) = 2.03x10 18 molecules H2
Totol gas particles = 2.05x10^18 molecules
The atom has only one isotope which means 100 % of same atom is present in nature. The atomic mass of an element is the number of times an atom of that element is heavier than an atom of carbon taken as 12. Mass of one atom of that isotope is 9.123 ✕ 10⁻²³ g, so mass of one mole of atom that is Avogadro's number of atom is 6.023 X 10²³ X 9.123 X 10⁻²³ g=54.94 g = 55 g (approximate).
So, the atom having atomic mass 55 will be Cesium (Cs). Only one isotope of Cesium is stable in nature.
Answer:
It can be removed by acidic chemicals
Explanation:
Answer:
pH → 7.46
Explanation:
We begin with the autoionization of water. This equilibrium reaction is:
2H₂O ⇄ H₃O⁺ + OH⁻ Kw = 1×10⁻¹⁴ at 25°C
Kw = [H₃O⁺] . [OH⁻]
We do not consider [H₂O] in the expression for the constant.
[H₃O⁺] = [OH⁻] = √1×10⁻¹⁴ → 1×10⁻⁷ M
Kw depends on the temperature
0.12×10⁻¹⁴ = [H₃O⁺] . [OH⁻] → [H₃O⁺] = [OH⁻] at 0°C
√0.12×10⁻¹⁴ = [H₃O⁺] → 3.46×10⁻⁸ M
- log [H₃O⁺] = pH
pH = - log 3.46×10⁻⁸ → 7.46
