Energy Transfers and Chemical Reactions

Flashcards for reviewing key concepts related to energy transfers, physical and chemical properties, and exothermic/endothermic reactions.

What is a physical property?

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

Give three 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, texture

What is a chemical property?

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

Give three examples of chemical properties.

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

What happens during a physical change?

The substance changes its form but not its chemical identity.

Give three examples of physical changes.

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

What can cause a physical change?

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

What happens during a chemical change?

A chemical reaction causes bonds between atoms to break or 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.

what happens when a exotherimc reaction occurs

The temperature rises.

What happens to the temperature of the surroundings during an endothermic reaction?

The temperature lowers.

In chemical reactions, what happens to bonds between atoms?

New bonds form between different types of atoms.

What is produced in chemical reactions?

New substances.

What two processes involving energy happens when bonds are broken and made?

Energy is taken in and released.

What does the reaction pathway diagram show?

It shows that the energy of the reactants is greater than the energy of the products, indicating it is an exothermic reaction.

What is the chemical formula for Magnesium chloride?

MgCl2

What is the relationship between energy of product and reactants in an exothermic reaction?

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

What are the first two learning objectives?

To interpret and sketch reaction profile. To explain why changes are described as being exothermic or endothermic.