Answer: She is incorrect to conclude that the reaction is endothermic.
As in the second trial, the temperature has increased by 20 °C , that means the heat has been released and energy is released in exothermic reactions.
Exothermic reactions: The reactions in which the energy of the products is less than the energy of the reactants, and the excess energy is released as heat.
Endothermic reactions: The reactions in which the energy of the products is more than the energy of the reactants, and the excess energy is absorbed as heat.
Answer:
714.285s
Explanation:
use relative velocity
8-4.5 = 3.5m/s
x = 2500m
2500/3.5 = 714.285s = 700s (with sig figs)
The correct is 72 watt
We know that formula of power is 
so putting the value of Voltage and Resistance in Formula of power so we get

What is Power?
Electric power is the rate at which an electric circuit transfers electrical energy per unit time.
Typically, electricity is generated by generators, but it can also be supplied by sources such as electric batteries. The electric power industry typically distributes it via an electric power grid to businesses and homes (as domestic mains electricity).
Transmission lines allow electric power to be delivered over long distances and used for high-efficiency applications such as motion, light, or heat. Electric charges are converted to other forms of energy when they pass through an electric potential difference (voltage).
To learn more about Power from the given link:
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