Heat Transfer: Endothermic and Exothermic Reactions Explained

The video tutorial explains endothermic and exothermic reactions, detailing how they absorb or release heat. It covers bond making and breaking, providing examples of each reaction type. Energy level diagrams are discussed, showing energy changes in reactions. The tutorial includes exam questions and a trick to identify reaction types based on moles of reactants and products.

What does the term 'exothermic' imply about a reaction?

• It involves no heat exchange.

• It requires light to proceed.

• It releases heat to the surroundings.

• It absorbs heat from the surroundings.

Which process is an example of an endothermic reaction?

• Burning a candle

• Condensation of water

• Melting ice

• Rusting of iron

What happens to energy when a bond is formed between two hydrogen atoms?

• Energy is converted to light.

• Energy remains constant.

• Energy is released to the surroundings.

• Energy is absorbed from the surroundings.

Which of the following is always true for a bond-breaking process?

• It is exothermic.

• It is endothermic.

• It releases energy.

• It requires no energy.

Which reaction is an example of an exothermic process?

• Melting ice

• Combustion of fuels

• Mixing water with ammonium nitrate

• Photosynthesis

Which process is an example of an endothermic reaction?

• Respiration

• Neutralization of acid and base

• Mixing water with potassium chloride

• Freezing water

In an exothermic reaction, how do the energy levels of reactants and products compare?

• Energy levels are not relevant.

• Reactants have lower energy than products.

• Reactants have higher energy than products.

• Reactants and products have the same energy.

What is the sign of the enthalpy change (ΔH) for an endothermic reaction?

• Zero

• Undefined

• Positive

• Negative

What is the trick to determine if a reaction is endothermic or exothermic based on moles?

• If n is greater than 0, it is exothermic.

• If n is less than 0, it is endothermic.

• If n is greater than 0, it is endothermic.

• If n is equal to 0, it is endothermic.

In the decomposition of calcium carbonate, what type of reaction occurs?

• Endothermic

• Neither

• Exothermic

• Both