Answer:
Mass percentage → 0.074 %
[F⁻] = 741 ppm
Explanation:
Aqueous solution of flouride → [F⁻] = 0.0390 M
It means that in 1L of solution, we have 0.0390 moles of F⁻
We need the mass of solution and the mass of 0.0390 moles of F⁻
Mass of solution can be determined by density:
1g/mL = Mass of solution / 1000 mL
Note: 1L = 1000mL
Mass of solution: 1000 g
Moles of F⁻ → 0.0390 moles . 19g /1 mol = 0.741 g
Mass percentage → (Mass of solute / Mass of solution) . 100
(0.741 g / 1000 g) . 100 = 0.074 %
Ppm = mass of solute . 10⁶ / mass of solution (mg/kg)
0.741 g . 1000 mg/1g = 741 mg
1000 g . 1 kg/1000 g = 1kg
741 mg/1kg = 741 ppm
Answer:
<em>hi..</em>
Explanation:
The lower mantle is hotter and denser than the upper mantle and transition zone. The lower mantle is much less ductile than the upper mantle and transition zone. Although heat usually correspond s to softening rocks, intense pressure keeps the lower mantle solid. Geologists do not agree about the structure of the lower mantle.
<em>hope this helps ._.</em>
Answer:
Voltaic cells convert chemical energy to electrical energy by means of an oxidation-reduction reaction. Electrolytic cells convert electrical energy to chemical energy, so they are the opposite of voltaic cells. They require an input of electrical energy to cause an oxidation-reduction reaction
Explanation:
A Galvanic cell converts chemical energy into electrical energy. An electrolytic cell converts electrical energy into chemical energy. Here, the redox reaction is spontaneous and is responsible for the production of electrical energy. I hope this is helpful.
12)
Answer: an endothermic reaction is where there is absorption of energy during the reaction. The energy of reactants is less than the energy of products.
As the enthalpy of the reaction is the difference in the total enthalpy of formation of products and total energy of formation of reactants and in endothermic reaction enthalpy is positive.
thus the energy of products is more than the energy of reactants.
The true statement is :The overall enthalpy of the system increases during the change.
Question 13
If the volume is lowered to one fourth it will increase the concentration (moles/volume). Thus, It will increase because the concentration of the reactants increases.
Question 14
As the value of equilibrium constant is in multiple of thousand, the reaction will be more favourable in forward direction hence
Ans: The equilibrium reaction mixture will have a very high concentration of products.
Question 15
As the system is in equilibrium and by decreasing the concentration of reactant we are disturbing the equilibrium state. In order to maintain the equlibrium the system will move in backward direction and hence
The rate of reverse reaction increases.