The answer is B.
A cannot be the answer is melting is a physical change. No chemical reaction took place.
B is the answer as it is a EXOTHERMIC REACTION so heat will be given off.
C cannot be the answer as dissolving is basically atoms becoming ions, not a chemical reaction whereby a reactant reacts with another reactant to form a product.
D cannot be the answer. Same reason as for why A is not the answer.
Cheers.
Answer:
It looks like its moving north.
Explanation:
1) 29.8 C
At the beginning, the metal is at higher temperature (70.4 C) while the water is at lower temperature (23.6 C). When they are put in contact, the metal transfers heat to the water, until they reach thermal equilibrium: at thermal equilibrium the two objects (the metal and the water have same temperature). Therefore, since the temperature of the water at thermal equilibrium is 29.8 C, the final temperature of the metal must be the same (29.8 C).
2) 6.2 C
The temperature change of the water is given by the difference between its final temperature and its initial temperature:

where

Substituting into the formula,

And the positive sign means that the temperature of the water has increased.
3) -40.6 C
The temperature change of the metal is given by the difference between its final temperature and its initial temperature:

where

Substituting into the formula,

And the negative sign means the temperature of the metal has decreased.
Answer:
F
Explanation:
The average velocity is the ratio of total displacement and time.The average speed is the ratio of total distance and time.Therefore the average speed and average velocity are equal if the total displacement is equal to the total distance that is if the body travels along a straight line without changing the direction.