Which statements are true?
check all that apply.
a. if heat is added to a substance, the temperature increases unless there is a phase change.
b. as heat is added to a substance, the temperature stays constant or goes down.
c. if heat is added to a substance, the temperature always increases.
d. during a phase change, the temperature of a substance does not change.

Heat is involved in chemical change in two ways; chemical changes either result in heat being added to or removed from an object, and chemical changes require a certain amount of heat before they can take place.

Answerchemical energy;

Answer:             1.0  × 10⁻⁵ msolution:                     as we know ph is given as,                                    ph  = -log [h⁺]and,                                    [h⁺]  =  10^-ph    (1)putting value of ph in eq. 1,                                    [h⁺]  =  10⁻⁵                                    [h⁺]  =  1.0  × 10⁻⁵ m