Water Warriors
This term refers to the presence of dissolved calcium and magnesium salts that prevent soap from lathering.
Response:
What is hardness of water?
Response:
What is hardness of water?
In the EDTA method, this indicator changes from wine red to blue at the endpoint, indicating complete complex formation.
What is Eriochrome Black T?
This is the potential difference between two electrodes of a galvanic cell when no current flows through the circuit.
What is the electromotive force (EMF) of the cell?
This is the gradual destruction of metals by chemical or electrochemical reaction with their environment.
What is corrosion?
This type of battery can be recharged and used multiple times by reversing the chemical reaction.
What is a secondary cell (or rechargeable battery)?
Hardness caused by bicarbonates of calcium and magnesium that can be removed by boiling.
What is temporary hardness?
This method of water softening uses a resin that exchanges sodium ions for calcium and magnesium ions.
What is the ion-exchange (zeolite) process?
This device is commonly used to measure the EMF of a cell accurately without drawing current.
What is a potentiometer?
In an electrochemical corrosion process, oxidation of the metal occurs at this part of the corrosion cell
What is the anode?
This light and high-energy-density rechargeable battery type is commonly used in laptops, mobile phones, and electric vehicles.
What is a lithium-ion battery?
The hardness of water is commonly expressed in this unit, equivalent to 10⁻⁵ kg of CaCO₃ per litre of water.
What is ppm (parts per million) as CaCO₃ equivalent?
In the EDTA titration, this buffer is used to maintain pH ≈ 10.
What is ammonium chloride–ammonium hydroxide buffer?
In a cell notation like Zn | Zn²⁺ || Cu²⁺ | Cu, the double vertical line (||) represents this component.
What is the salt bridge?
This type of corrosion occurs when two dissimilar metals are electrically connected in the presence of an electrolyte.
What is galvanic corrosion?
A hydrogen–oxygen fuel cell produces electricity directly from this type of energy conversion.
What is chemical energy to electrical energy?
This process uses EDTA as a complexing agent to estimate the hardness of water.
What is the complexometric titration method?
Hardness in boiler feed water can lead to these two major problems.
What are scale formation and sludge formation?
According to the Nernst equation, the EMF of a cell decreases when this parameter increases for the product ions.
What is concentration?
In the impressed current method of cathodic protection, corrosion is prevented by applying this to make the structure act as a cathode.
What is an external DC electrical current?
In a Li-ion battery, lithium ions move from this electrode to the other during discharge.
What is from the anode to the cathode?
In chlorination, this term refers to the point where addition of chlorine results in complete oxidation of organic matter and ammonia.
What is the break-point chlorination?
The hardness of a water sample containing 100 mg/L Ca²⁺ and 24 mg/L Mg²⁺ (as ions) is approximately how much as CaCO₃ equivalent?
What is 356 mg/L as CaCO₃?
(Calculation: Hardness = (100×2.5) + (24×4.1) = 356 mg/L)
If the standard reduction potentials of Cu²⁺/Cu and Zn²⁺/Zn are +0.34 V and –0.76 V respectively, the EMF of the Zn–Cu cell is this value.
What is 1.10 V?
This highly localized form of corrosion results in small holes or cavities on the metal surface, often due to the breakdown of a protective film.
What is pitting corrosion?
The relationship between cell EMF and equilibrium constant (K) is given by this equation
What is E° = (0.0591/n) log K at 25°C?