Answer:
C) 
Explanation:
pH is defined as the negative logarithm of the concentration of hydrogen ions.
Thus,
pH = - log [H⁺]
The expression of the pH of the calculation of weak acid is:-
Where, C is the concentration = 0.5 M
Given, pH = 2.94
Moles = 0.100 moles
Volume = 1.00 L
So, 
C = 0.100 M



C is the right answer as endothermic reaction takes in the heat. That is why cooling effect is observed whenever such reaction takes place.
Hope this helped :)
Radioisotopes are used to study chemical reactions because of the fact that they attach radioactive isotopes to certain atoms.<span> Tracer radioisotopes used to study chemical reactions in molecular structures by adding radioistopes to reactants and using the uptake compared to the original isotope. </span>
Answer:
–698 kJ/mol
Explanation:
i guessed and got it right
Galileo was the first scientist to measure speed as distance over time.