Question

is the thermal energy that flows from one substance to another when the substances differ in temperature.

Answer 1

yes, because the heat flow from higher temperatures or energy to lower temperature or energy.

Answer 2

Yes, the statement mentioned in the question is completely justified.

When two different substances are in different temperatures,the thermal energy flows from the high temperature substance to the low temperature substance untill both of them reaches the same temperature.

(The thermal flow only happens when the two substances are physically connected or in touch with each other.)