Two examples of chemical reactions that involved a thermal energy change: 1. NH4NO3 (s) + heat ---> NH4+ (aq) + NO3 (aq)
2. CaCl2 (s) + 2H20 ---> Ca(OH)2 (aq) + 2HCl (g) + heat
Which is exothermic? Which is endothermic? How do you know?

Option 1 is endothermic

Option 2 is exothermic

Explanation:

In Chemistry, Exothermic reactions are reactions whereby heat energy is transferred to the surroundings and the temperature of the surroundings increases. Endothermic reactions are those whereby heat energy from the surroundings is absorbed and thereby making the temperature of the surroundings to decrease.

This means in simple terms that endothermic reactions will have heat on the reaction side of the equation while exothermic will have heat on the product side of the equation.

Thus;

Option 1 is endothermic since it has heat absorbed on the reactant side.

Option 2 is exothermic since it gives off heat on the product side.

explanation: magnetic pole, region at each end of a magnet where the external magnetic field is strongest. the south-seeking pole, or any pole similar to it, is called a south magnetic pole. unlike poles of different magnets attract each other; like poles repel each other.

a.metals can become magnetic if they have many spinning electrons that create magnetic fields.d.only some metals are attracted by magnets; these metals are called ferromagnetic.

d.wrapping an insulated wire around a metal with ferromagnetic properties and applying an electric current.