Answer:
-1273.3
Explanation:
Enthalpy of formation of a compound is the amount of heat absorbed or evolved when one mole of the compound is formed from other compounds.
enthalpy of formation Of CO2 = 2 X -393.5 = -787
enthalpy of formation Of C2H5OH = 2 X -277.7 = -555.4
enthalpy of formation Of C6H12O6 = 69.1 (reverse sign) + (-787 + -555.4) = - 1273.3 Joules
Answer:
1. Galvanic oxidation. Example is the corrosion of aluminium wires when in contact with copper wires under wet conditions.
2. Rainwater or Damp/moist air
3. Chromium-plated steel screws or stainless steel screws or galvanized steel screws
Explanation:
1. Galvanic oxidation or corrosion occurs when two different metals with different electrode potentials are brought into contact with each other by means of an electrolyte (usually a aqueous solution), such that a redox reaction occurs leading to one metal with the more negative electrode potential (the anode) becoming oxidized, while the other less negative potential (the cathode) is reduced.
In order for galvanic corrosion to occur, three elements are required.
i. Two metals with different corrosion potentials (anode and cathode)
ii. Direct metal-to-metal electrical contact
iii. A conductive electrolyte solution (e.g. water) must connect the two metals on a regular basis.
For example oxidation (corrosion) of aluminium wires when in contact with copper wire under wet conditions.
2. The most likely electrolyte will be rainwater containing dissoved solutes (if the panel is in an exposed part of the house) or damp/moist air.
3. From the table, the most likely screw will be chromium-plated steel screws or stainless steel (made of iron and nickel) screws or galvanized steel (zinc-plated) screws.
All these possible screw components have a more negative electrode potential than copper. Thus they will serve as the anode in a galvanic oxidation with copper.
Answer: The stick model method
Answer:
The cell reaction reaches equilibrium quickly and the cell emf becomes zero.
Explanation:
The purpose of a salt bridge is not to move electrons from the electrolyte, its main function is to maintain charge balance because the electrons are moving from one-half cell to the other.
A solution of a salt that dissociates easily is normally used. Water is ineffective at functioning as a salt bridge. Hence the effect stated in the answer.
Answer:
After measuring the solute, Carl should first dissolve the solid in a small amount of DI water before diluting to the total volume.
Explanation:
To ensure that all the solute dissolves in the solution, first dissolve the solid in less than the total volume of solution needed.
