Answer:
The answer is: (a) positive; (b) negative.
Explanation:
The change in enthalpy (ΔH) of a reaction is the amount of energy absorbed or released during a chemical reaction carried out at constant pressure.
a) In an endothermic chemical reaction, heat energy is absorbed by the system from the surrounding. Therefore, the sign of enthalpy change for an endothermic process is positive, ΔH= positive.
b) In an exothermic chemical reaction, heat energy is released by the system into the surrounding. Therefore, the sign of enthalpy change for an exothermic process is negative, ΔH= negative.
What do you want for the answer the balance equation?
Most reasonable answer:
Observations and experimentation
Answer:
The rain falling in New England is 2.29 times more acidic than the one in the American Midwest.
Explanation:
The acidity of a solution depends on the concentration of H⁺ ions ([H⁺]). We can calculate this concentration from the pH using the following expression.
pH = -log ([H⁺])
American Midwest
pH = -log ([H⁺])
5.02 = -log ([H⁺])
[H⁺] = antilog (-5.02) = 9.55 × 10⁻⁶ M
New England
pH = -log ([H⁺])
4.66 = -log ([H⁺])
[H⁺] = antilog (-4.66) = 2.19 × 10⁻⁵ M
The ratio of concentrations is:
The rain falling in New England is 2.29 times more acidic than the one in the American Midwest.
Answer:
2.57 e-9
Explanation:
The formula is H3O=10^-Ph
10^-8.59=2.57 e-9