Answer:
Regional metamorphic rocks form from other rocks (protoliths) by changes in mineralogy and texture in response to changing physical conditions (temperature, lithostatic pressure, and, in most cases, shear stress). Regional metamorphism occurs over broad areas in the lithosphere, possibly influenced by the heat supply. Regional metamorphic rock results from regional metamorphism and usually develops a flaky texture.  These changes are essentially solid-state reactions, but very often a fluid phase is present, either participating in the reaction or as a reaction medium. Many regional metamorphic rocks have a chemical composition that is very similar to that of their sedimentary or igneous precursors, with the exception of removal or addition of volatiles (mainly H2O and CO2). This type of behavior is termed isochemical metamorphism. Metamorphism may also take place as a result of a change in chemical environment; this may occur by transport of elements between chemically contrasting rock types (e.g., formation of calc-silicate minerals at a quartzite–marble contact) or by circulation of fluids that dissolve some substances and precipitate others. This process of significant chemical change during metamorphism is known as allo-chemical metamorphism or metasomatism, and rocks formed in this manner are metasomatic rocks. Metasomatism is, however, mostly of local significance, and the total volume of metasomatic rocks in regional metamorphic terranes is rather minor. The distinction between metasomatism and is chemical metamorphism is also a matter of scale. On the scale of individual grains, mass transport takes place during all phase transformations; on the scale of a thin section, it is probably the rule for regional metamorphism; on the scale of a hand (sized) specimen, it can be observed frequently; and on a larger scale, it is the exception.
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Answer:
14. B    15. D    16. C     17. B
Explanation:
The spontaneous reaction that occurs when the cell operates is shown below:
 ⇒
 ⇒
We need to select the correct option from the list below for the following questions.
(A) Voltage increases. (B) Voltage decreases but remains > zero. (C) Voltage becomes zero and remains at zero. (D) No change in voltage occurs. (E) Direction of voltage change cannot be predicted without additional information. 
14. A 50-milliliter sample of a 2-molar  solution is added to the left beaker.
 solution is added to the left beaker. 
If a 50-milliliter sample of a 2-molar  solution is added to the left beaker, the voltage decreases but its value remains greater than zero. The correct option is B
  solution is added to the left beaker, the voltage decreases but its value remains greater than zero. The correct option is B
15. The silver electrode is made larger.
If the silver electrode is made larger, no change in the value of the voltage since we don't have the idea of the initial value. The correct option is D.
16. The salt bridge is replaced by a platinum wire. 
If the salt bridge is replaced by a platinum wire, there will be no passage of electrons because electrons can't pass through a platinum wire. Therefore, the voltage will be zero and remains at zero. The correct option is C.
17. Current is allowed to flow for 5 minutes.
If current is allowed to flow for 5 minutes, the voltage decreases but its value remains greater than zero. The correct option is B.
 
        
             
        
        
        
This substance most likely is an inert. It is a substance that is not chemically reactive. It does not change its chemical nature in a reaction. It does not <span>easily react with other chemicals. Most of the group 8 gases in the periodic table are classified as inert, due to their having full outer electron shells. </span>
        
                    
             
        
        
        
Delta T= T final - T initial
Tfinal= -101.1 °C
Tinitial= -0.5 °C
•Delta T = -101.1°C - (-0.5°C)
 =100.6°C
Kelvin= °C + 273
 = -100.6 + 273
 = 172.4 Kelvin
        
             
        
        
        
<u>Answer:</u> The molar mass of unknown triprotic acid is 97.66 g/mol
<u>Explanation:</u>
To calculate the molarity of acid, we use the equation given by neutralization reaction:

where,
 are the n-factor, molarity and volume of triprotic acid
 are the n-factor, molarity and volume of triprotic acid
 are the n-factor, molarity and volume of base which is NaOH.
 are the n-factor, molarity and volume of base which is NaOH.
We are given:

Putting values in above equation, we get:

To calculate the molecular mass of solute, we use the equation used to calculate the molarity of solution:

We are given:
Molarity of solution = 0.0077 M
Given mass of triprotic acid = 0.188 g
Volume of solution = 250 mL
Putting values in above equation, we get:

Hence, the molar mass of unknown triprotic acid is 97.66 g/mol