Answer:
(a) PbSO4 anode is reduced to Pb.
Explanation:
Cells which can be recharged are known as secondary cells. They can be recharged by passing a direct current through them. An example of a secondary cell is the lead storage battery used in motor cars.
During the process of recharging, the electrodes in the cell are reversed from what we have know to occur during discharging because it is electrolized.
At the anode: The lead (II) tetraoxosulphate (VI) absorbs two electrons to become reduced to Pb. Thus at the anode PbSO₄ is reduced to Pb.
At the cathode:
The electrons from the anode are accepted at the cathode where the lead (iV) oxide is oxidised into lead (II) ions.
0.150 M AgNO3 = x mol / 0.200 Liters
x mol = 0.03 mol AgNO3
0.03 mol AgNO3 (169.9g AgNO3 / 1 mol AgNO3) We are converting moles to grams here with stoichiometry.
Final answer = 5.097 grams, but if you want it in terms of sig figs then it is 5.09 grams.
Answer:
The correct answer is:
<em>(1) It is important that the sample is dissolved in just enough hot solvent. </em>
Explanation:
The process of recrystallization is important to eliminate the impurities and to obtain better crystals of the solid. The solvent used to perform the recrystallization must have a high dissolution power of the substance to be recrystallized and a low dissolution power of the impurities. This is in order to eliminate most impurities. Furthermore, <em>It is important that the sample is dissolved in just enough hot solvent </em>because this should be easy to remove after the recrystallization and the crystal should form easily when the solution cools. Also, it is better to add the hot solvent to solubilize the crystals and keep the impurities insoluble, instead of adding the cold solvent and heating the solution. Additionally, the process of cooling the solution must be done slowly to obtain large and fewer crystals. A fast ice-cooling will form smaller crystals.
Answer:
The balanced chemical equation :
Explanation:
When calcium hydroxide reacts with hydrochloric acid it gives calcium chloride and water as a products. The chemical equation is given as:
According to question, solid calcium hydroxde is added to 38.0 mL of 0.410 M of HCl solution, so the chemical equation can be written as:
According to stoichiometry, when 1 mole of solid calcium hydroxide reacts with 1 mole of hydrochloric acid to gives 1 mole of aqueous calcium chloride and 1 mole of water.