Consider a beaker of water that has an initial temperature of 25 degree centigrade. when an ionic salt is dissolved in the water, the temperature changes to 5 degree centigrade.

1. what would you feel if you touch the beaker.
2. is the energy of the product higher or lower than the energy of the reactant?
3. is this reaction endothermic or exothermic?

1. If you touch the beaker, you would feel that it is cold because the temperature has dropped from 25 degrees Celsius to 5 degrees Celsius.

2. The energy of the product is lower than the energy of the reactant. When the salt dissolves in water, it releases energy, causing the temperature to decrease. This indicates a decrease in the energy level of the system.

3. This reaction is exothermic. An exothermic reaction releases energy in the form of heat. In this case, when the salt is dissolved in water, it releases energy, resulting in a decrease in temperature.

To answer these questions, we need to understand the concepts of temperature change, energy changes in reactions, and the classification of reactions as endothermic or exothermic. Let's break it down step by step:

1. What would you feel if you touch the beaker?
If the temperature of the water decreases from 25°C to 5°C, the beaker would feel cold to the touch. This is because heat transfer occurs from the warmer object (your hand) to the cooler object (the beaker), resulting in a sensation of coldness.

2. Is the energy of the product higher or lower than the energy of the reactant?
Based on the information provided, we know that the temperature of the water decreased after the ionic salt was dissolved. Temperature is an indicator of the average kinetic energy of particles in a substance. So, when the temperature decreases, it means that the average kinetic energy of the water molecules has also decreased.

Considering this, we can infer that the energy of the product (water with dissolved salt) is lower than the energy of the reactant (pure water) because the water's temperature has decreased. Heat energy has been transferred from the water to the surroundings during the dissolution process, leading to a decrease in temperature.

3. Is this reaction endothermic or exothermic?
In a reaction, when the energy of the products is lower than the energy of the reactants, it indicates that energy was released from the system into the surroundings. This type of reaction is called an exothermic reaction.

Therefore, based on the temperature decrease and the concept of energy changes, the dissolution of the ionic salt in water would be classified as an exothermic reaction because heat energy is released from the system (water) into the surroundings.

1. Technically it depends upon the temperature of your hand: if we assume the body temperature is 37 C then your hand is warmer than the beaker and the beaker will feel cold.

2. This must be a separate question and has nothing to do with question #1. If the beaker changes from 25 C to 5 C the energy is lower.

3. This is an endothermic reaction.

Thank you very much DrBobb22.