The kinetic molecular theory<span> of gases is stated in the following four </span>principles<span>: The space between gas </span>molecules<span> is much larger than the </span>molecules<span> themselves. Gas </span>molecules<span> are in constant random motion. The average </span>kinetic<span> energy is determined solely by the temperature.
I got this from my notes from my chemistry class last semester
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Answer: <span>A fewer number of particles of the sample will dissolve in 1 minute.
That is because normally the solubility and rate of solubility of the salts in water increase with the temperature. This is, the higher the temperature the higher and faster the number of particles that the water can dissolve. So, at 70°C more particles will be dissolved in water in 1 minute than at 20°C.
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<span>the atomic mass of nitrogen is 14. There is 1 nitrogen atom in the molecule so the percentage of N is :
14/35 x100% = 40%</span>
Answer : The radii of the two ions Cl⁻ ion and Na⁺ ion is, 181 and 102 pm respectively.
Explanation :
As we are given that the Na⁺ radius is 56.4% of the Cl⁻ radius.
Let us assume that the radius of Cl⁻ be, (x) pm
So, the radius of Na⁺ = 
In the crystal structure of NaCl, 2 Cl⁻ ions present at the corner and 1 Na⁺ ion present at the edge of lattice.
Thus, the edge length is equal to the sum of 2 radius of Cl⁻ ion and 2 radius of Na⁺ ion.
Given:
Distance between Na⁺ nuclei = 566 pm
Thus, the relation will be:





The radius of Cl⁻ ion = (x) pm = 181 pm
The radius of Na⁺ ion = (0.564x) pm = (0.564 × 181) pm =102.084 pm ≈ 102 pm
Thus, the radii of the two ions Cl⁻ ion and Na⁺ ion is, 181 and 102 pm respectively.