Answer: The standard free energy change for a reaction in an electrolytic cell is always positive.
Explanation:
Electrolytic cells use electric currents to drive a non-spontaneous reaction forward.
Relation of standard free energy change and emf of cell
where,
= standard free energy change
n= no of electrons gained or lost
F= faraday's constant
= standard emf
= standard emf = -ve , for non spontaneous reaction
Thus 
Thus standard free energy change for a reaction in an electrolytic cell is always positive.
Insect's or Bugs preserved in Amber
Fireworks owe their colors to reactions of combustion of the metals present. When Mg and Al burn, they emit a white bright light, whereas iron emits a gold light. Besides metals, oxygen is necesary for the combustion. The decomposition reactions of barium nitrate and potassium chlorate provide this element. At the same time, barium can burn emitting a green light.
(a) Barium nitrate is a <em>salt</em> formed by the <em>cation</em> barium Ba²⁺ and the <em>anion</em> nitrate NO₃⁻. Its formula is Ba(NO₃)₂. Potassium chlorate is a <em>salt</em> formed by the <em>cation</em> potassium K⁺ and the <em>anion</em> chlorate ClO₃⁻. Its formula is KClO₃.
(b) The balanced equation for the decomposition of potassium chloride is:
2KClO₃(s) ⇄ 2KCl(s) + 3O₂(g)
(c) The balanced equation for the decomposition of barium nitrate is:
Ba(NO₃)₂(s) ⇄ BaO(s) + N₂(g) + 3O₂(g)
(d) The balanced equations of metals with oxygen to form metal oxides are:
- 2 Mg(s) + O₂(g) ⇄ 2 MgO(s)
- 4 Al(s) + 3 O₂(g) ⇄ 2 Al₂O₃(s)
- 4 Fe(s) + 3 O₂(g) ⇄ 2 Fe₂O₃(s)
The boiling of water and sublimation of iodine crystals are endothermic processes.
Answer: Option B & C
Explanation:
Endothermic process are the classifications of chemical reactions where the heat is absorbed by the system from the surroundings. As the matters can exists in three phases like solid, liquid and gases.
The endothermic process occurs by absorption of heat energy by the system. So according to the given options, the boiling of water and iodine crystal sublimation follows endothermic process. In the boiling of water occurs when the water molecules absorb heat from the surrounding and convert to gas phase.
Similarly, the sublimation of iodine crystals also require heat energy from the surrounding to break the bonds of the iodine crystals to sublimate to gas phase. Thus the boiling of water and sublimation of iodine crystals are the examples of endothermic processes.
Answer:
Without trees formerly forested areas would become drier and more prone to extreme droughts. When and if rain did come flooding would be disastrous and massive erosion would impact oceans smothering coral reefs and other marine habitats
Explanation:
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