9Hb/Energy Transfers Lecture Notes

Flashcards based on lecture notes covering energy transfers, physical and chemical properties and changes, and exothermic and endothermic reactions.

What are the two main objectives covered in this lesson?

To interpret and sketch reaction profiles, and to explain exothermic and endothermic changes.

What is the definition of a physical property?

A characteristic of a substance that can be observed without changing the substance into another substance.

Provide examples of physical properties.

Volume, mass, weight, heat conductivity, electrical conductivity, solubility, shape, viscosity, ductility, malleability, size, density, color, hardness, odor, melting point, boiling point, taste, state of matter, and texture.

What is the definition of a chemical property?

A characteristic of a substance that can only be observed by changing it into a different substance.

Give examples of chemical properties.

The ability to burn, ability to tarnish, ability to rust, ability to decompose, ability to react with other chemicals, instability, and ability to do acid/base reactions.

What are some examples of physical changes?

Change in shape, change in size, change in phase, melting, boiling, evaporation, condensation, freezing, sublimation, and deposition.

What are the processes of phase changes between solid, liquid, and gas?

Sublimation (solid to gas), deposition (gas to solid), vaporization (liquid to gas), condensation (gas to liquid), fusion/melting (solid to liquid), and freezing (liquid to solid).

What might cause physical changes?

Grinding, cutting, crushing, bending, breaking, heating/cooling, and squishing.

When do chemical changes occur?

When a chemical reaction causes bonds between atoms to break or to form.

What forms of energy can be released during a chemical change?

Heat and light.

What is an exothermic reaction?

A chemical reaction that releases energy in the form of heat.

What is an endothermic reaction?

A chemical reaction that absorbs energy in the form of heat.

How do exothermic reactions affect the temperature of their surroundings?

They cause a rise in temperature of things around them.

How do endothermic reactions affect the temperature of their surroundings?

They lower the temperature of their surroundings.

In a reaction profile, what indicates an exothermic reaction?

The energy of the reactants is greater than the energy of the products.