Coulomb's law mathematically is:
F = kQ₁Q₂/r²
we integrate this with respect to distance to obtain the expression for energy:
E = kQ₁Q₂/r; where k is the Coulomb's constant = 9 x 10⁹; Q are the charges, r is the seperation
Charge on proton = charge on electron = 1.6 x 10⁻¹⁹ C
E = (9 x 10⁹ x 1.6 x 10⁻¹⁹ x 1.6 x 10⁻¹⁹) / (185 x 10⁻¹²)
E = 1.24 x 10⁻¹⁸ Joules per proton/electron pair
Number of pairs in one mole = 6.02 x 10²³
Energy = 6.02 x 10²³ x 1.24 x 10⁻¹⁸
= 746.5 kJ
Answer: 1.85M
Explanation:
Sodium hydroxide has a chemical formula of NaOH
Given that,
Amount of moles of NaOH (n) = ?
Mass of NaOH in grams = 63g
For molar mass of NaOH, use the molar masses:
Sodium, Na = 23g;
Oxygen, O = 16g;
Hydrogen, H = 1g
NaOH = (23g + 16g + 1g)
= 40g/mol
Since, amount of moles = mass in grams / molar mass
n = 63g / 40.0g/mol
n = 1.575 mole
Volume of NaOH solution (v) = 850mL
[Convert 850mL to liters
If 1000mL = 1L
850mL = 850/1000 = 0.85L]
Concentration of NaOH solution (c) = ?
Since concentration (c) is obtained by dividing the amount of solute dissolved by the volume of solvent, hence
c = n / v
c = 1.575 mole / 0.85L
c = 1.85M [1.85M is the concentration in moles per litres which is also known as molarity]
Thus, the molarity of the solution is 1.85M
I a chemical reaction, we have the reactants in the left part,followed by an arrow and then the products.
So, the reactants are the two that are in the left part of the equation:
Sodium hydroxide and Hydrochloric acid
