Respuesta :
1) Answer: A hot pack feels warm when chemicals in it combine.
Explanation: Reactions or process in which heat is released(produced) are known as exothermic reactions or process and those in which the heat is absorbed are known as endothermic reactions or process.
If a beaker feels cools when chemical in it react then it means the chemicals have absorbed the heat energy from its surroundings and so it is an example of an endothermic process.
A hot pack feels warm when chemicals in it combine means the energy is released in the chemical reaction and so it is an example of an exothermic process.
Plants use the sun's energy for photosynthesis which is a process of forming food for the plants. Energy acts as a reactant in this process and so it is an example of endothermic process.
Frying an egg by heating it on a stove is an example of an endothermic process as the heat is required to fry the egg.
So, the only exothermic process is the second one, "A hot pack feels warm when chemicals in it combine."
2) In the given equation, heat is written as a product means the heat is released in the equation and so it is an example of an exothermic reaction.
So, the correct choice is the last one " It is exothermic because energy is released."
Question 1
An example of an exothermic process is, A hot pack feels warm when chemicals in it combine.
Further Explanation;
Energy changes in chemical reactions
- Chemical reactions are accompanied by energy changes, as energy is either absorbed to break chemical bonds or released when bonds are formed.
- Chemical reactions are therefore classified as endothermic reactions or exothermic reactions.
Exothermic reactions
- Exothermic reactions are types of reaction that release energy to the surrounding.
- In these reactions energy is released when new bonds are formed during the reactions. More energy is released when bonds are formed in the products than is used to break bonds in the reactants.
- Therefore exothermic reactions have a negative (-) enthalpy change (ΔH).
Endothermic reactions
- Endothermic reactions are type of reactions that absorb energy from the surroundings.
- In these type of reactions more energy is absorbed when bonds of the reactants are broken than the energy released when bonds of the products are formed.
- Endothermic reactions have a positive (+) enthalpy change (ΔH).
Keywords: Chemical reactions, energy changes in chemical reactions, exothermic reactions, endothermic reactions.
Question 2
The statement that describes the reaction;
N2(g) + 3H2(g)---> 2NH3(g) + 93 kJ is
The reaction is an endothermic reaction because energy is absorbed
Further Explanation;
Enthalpy of a reaction (ΔH)
- Enthalpy chnage of a reaction or heat change is the difference between the enthalpy of products and the enthalpy of reactants.
- Enthalpy change can be used to determine whether a reaction is exothermic or endothermic.
- ΔH = energy used in bond breaking of reactant + energy released in bond formation of product.
Endothermic reactions
- Endothermic reactions have a positive (+) enthalpy change (ΔH) because less energy is released when the products are formed compared to the energy used to break up the bonds in reactants.
Exothermic reactions
- Exothermic reactions have a negative(-) enthalpy change (ΔH) since more energy released when the products are formed compared to energy used to break bonds in reactants.
Keywords: Enthalpy change, heat change, exothermic reactions, endothermic reactions.
Learn more about
- Energy changes in chemical reactions: https://brainly.com/question/2217125
- Ethalpy change; https://brainly.com/question/1127247
- Endothermic reactions: https://brainly.com/question/1127247
- Exothermic reactions: https://brainly.com/question/1831889
Level: High school
Subject: Chemistry
Topic: Chemical reactions
Sub-topic: Energy changes in chemical reactions
