Unit B Matter and Chemical Change: Section 4.0 Flashcards
When does a chemical reaction take place?
When two or more substance combine to form a new substance
What are the materials at the start of a reaction called?
Reactants
What are the new materials called?
Products
In a chemical equation, what is the purpose of the addition signs?
Separate the reactants from each other and the products from each other
What is the significance of the arrow in a word or symbol chemical reaction?
Separate the reactants and the products and show the direction of the chemical reaction.
What is evidence of a chemical change?
Change in Color
Change in odour
Formation of solid or gas
Release of absorption or heat
What is an endothermic reaction?
A chemical reaction that absorbs heat energy
What does an endothermic reaction feel like?
Cold to the touch
What is an exothermic reaction?
A chemical reaction that releases heat energy
What does an exothermic reaction feel like?
Warm to the touch
What is combustion?
A chemical reaction that occurs when oxygen reacts with a substance and gives off energy
What is corrosion?
The slow chemical change that occurs when oxygen in the air reacts with metal
What is Cellular Respiration?
A chemical reaction that takes place in the cells in your body. Food reacts with oxygen to produce energy, water, and carbon dioxide
What is the law of conservation of mass?
That matter is not created or destroyed in a chemical change
What is an open system?
A reaction is open to the environment
What is a closed system?
No additional matter is allowed to enter or leave
What four factors affect the rate of a chemical reaction?
The presence of a catalyst
The concentration of reactants
The temperature of the reactants
The surface area of the reactants
What are catalysts?
Substances that help a reaction proceed faster. They are present with the reaction but are not consumed during the reaction
How does the concentration help the rate of a chemical reaction?
The greater the concentration of the reactant the faster the reaction
How does temperature affect the rate of a chemical reaction?
The more heat added to the reactants the faster the reaction. The heat causes the atoms to move faster increasing the chances of their colliding with each other.
how does surface area affect the rate of a chemical reaction?
The greater surface area means more area is available for reaction
