Energy and Chemical Reactions Flashcards
What is energy?
The capacity to do work
What are 2 types of energy?
- kinetic (energy of motion)
- potential (energy of position)
What are the 4 forms of energy?
- mechanical
- radiant
- electrical
- chemical
What is mechanical energy?
- energy involved in moving matter
- muscles provide mechanical energy to move objects
What is radiant energy?
- kinetic energy of electromagnetic waves (heat and light) also called electromagnetic radiation
- skin uses ultraviolet light to make vitamin D
- the eye is sensitive to visible light
What is electrical energy?
- kinetic energy of charged particles travelling through a medium
- responsible for transmission of impulses in nerve and muscle cells
What is chemical energy?
- potential energy stored in bonds between atoms and molecules
- energy required to make a bond
- energy released when bonds are broken
What is a reactant?
A substance entering the reaction
What is a product?
A substance produced by a reaction
What is a chemical reaction?
- a chemical reaction rearranges the atoms of reactants to create different products
- is governed by the law of conservation of mass (in a closed system, no atoms are created or destroyed)
- mass of the products = mass of the reactants
What is metabolism?
- the sum of all chemical reactions, within a living organism
What are the 2 types of reactions that make up metabolism?
- Anabolic reactions (bond formation; requires input of energy, endergonic)
- Catabolic reactions (bond breaking; releases energy, exergonic)
What are the 3 types of reactions?
- Synthesis
- Decomposition
- Exchange
What is a synthesis reaction?
- 2 components bond to make larger molecules
- these reactions are anabolic and endergonic (requires input of energy)
- ex. N + 3H ——> NH3
What is a decomposition reaction?
- bonds between components of a larger molecule are broken, resulting in smaller products
- these reactions are catabolic and exergonic (breaks down bonds)
- ex. NH3 ——> N + 3H
What is an exchange reaction?
- bonds are formed and broken down such that reactants are rearranged
- ex. 4NH3 + 3O2 —–> 2H2 + 6H2O
Most reactions in the human body have a predictable direction. True or false?
True
In theory, reactions are reversible. True or false?
True
What are the properties that influence reaction rate?
Properties of Reactant: Surface area, gases/liquids/solids, how reactive the elements are
Temperature: Thermal energy increases the kinetic energy of subatomic particles
Concentration and Pressure: Makes it more likely for particles to collide
Catalyst: A substance that increases the rate of a chemical reaction without changing itself
- this is an enzyme: a protein that speeds up a reaction by lowering the activation energy
What is activation energy?
The minimum energy needed to break down the bonds on reactants
What is the function of an enzyme as a catalyst?
It means that less activation energy is required in the presence of an enzyme
