Physical & Chemical Changes Flashcards
Define Physical Change
A physical change is one in which there is no new substances are formed and one that can easily be reserved by changing the conditions usually no, or little heat is taken in or given out.
Define Chemical Change.
A chemical change is one in which a chemical reaction occurs and new substances are created.
What is the observation of the reaction of magnesium heated with oxygen?
Brilliant white light and highheat is given out white. White ash-> Magnesium oxide.
What are characteristics of chemical change?
Chemical change:
- New substances are found
- Chemical reaction occurs
- A large amount of heat is taken in/given out-
- Irreversible
- Properties of products are different from the reactants
What are the characteristics of physical change?
Physical change:
- No new substances are formed
- No chemical reaction occurs
- Little amount of heat is taken in/ given out
- Reversible
- There is no change in the properties of substances involved.
What does the chemical equation, arrow represent?
Represent the order and direction of reaction.
Chemical Changes can be caused by?
- Heat
2, Light - Using Electricity
- Mixing of Chemicals
What are some types of chemical changes?
- Direct Combination
- Combustion
- Thermal Decomposition
- Neutralization
Direct Combination-
When 2 or more elements are heated together
heat is required.
Combustion reaction-
Substances, when heated react with oxygen. heat and light are often accompanied a combustion reaction.
Oxygen supports Combustions
Thermal Decomposition-
When substances decompose (break down) into simpler substances by heat.
What are two examples of mixing of chemicals.
Precipitation Reaction
Neutralization Reaction
Light is needed for __________________
Light is needed for photosynthesis in plants to take place.
Electricity is needed for _________________.
Electricity for decomposition of certain substances.
Precipitation reaction.
When to aqueous solutions are mixed.
