Matter is anything that occupies space and has mass.
It exists in solid, liquid and gaseous states.
1 of 24
Define energy
Energy is the ability to do work or to move matter.
It has no mass and doesn't occupy space. It can only be measured by it's effects on matter.
2 of 24
What are the two types of energy?
Kinetic energy - when energy is doing work
Potential energy - when energy is inactive/ stored
3 of 24
What are the forms of energy?
Chemical energy
Electrical energy
Mechanical energy
Radiant energy
4 of 24
What is chemical energy?
This is stored in the bonds of chemical substances.
When the bonds are broken the potential energy is unleashed and becomes kinetic energy.
5 of 24
What is electrical energy?
This results from the movement of charged particles (ions).
An electrical current is generated when ions move across cell membranes from one part of the body to another.
6 of 24
What is mechanical energy?
Energy directly involved in moving matter.
E.g. when you pedal a bicycle, your legs provide the mechanical energy that turns the wheels.
7 of 24
What is radiant energy?
This travels in waves; it is the energy of the electromagnetic spectrum.
8 of 24
Why are energy form conversions not very efficient?
Some of the initial energy supply will be lost to the environment as heat (thermal energy).
9 of 24
Define 'elements'
Substances that cannot be broken down into simpler substances by chemical means. Elements are made up of atoms.
10 of 24
List the four elements that form the bulk of body matter.
Carbon, oxygen, hydrogen and nitrogen
These form 96% of the weight of the human body.
11 of 24
What are atoms composed of?
Three subatomic particles -
Protons (positive charge)
Neutrons (no charge)
Electrons (negative charge)
12 of 24
What is the atomic number?
This is equal to the number of protons in the atom.
13 of 24
What is the atomic mass number?
The sum of the protons and neutrons contained in the atoms nucleus.
14 of 24
Define 'molecule'
A molecule is formed when two or more atoms combine chemically.
E.g. when two hydrogen atoms bond, the molecule of hydrogen gas is formed.
15 of 24
What are ionic bonds?
These form when electrons are completely transferred from one atom to another. Creating charged particles (ions).
Gaining electrons results in a negative charge (anions).
Losing electrons results in positively charged ions (cations).
16 of 24
What are covalent bonds?
This is where electrons are shared, so that both atoms fill their valence (outer) shell.
17 of 24
What are the three patterns of chemical reactions?
Synthesis reactions
Decomposition reactions
Exchange reactions
18 of 24
What are synthesis reactions?
Occur when two or more atoms or molecules combine to form a larger, more complex molecule.
(Synthesis reactions always involve bond formation).
19 of 24
What are decomposition reactions?
Occur when a molecule is broken down into smaller molecules, atoms or ions.
(Bonds are always broken, and the products of these reactions are smaller and simpler than the original molecules.)
20 of 24
What are exchange reactions?
Simultaneous synthesis and decomposition reactions
21 of 24
Define 'inorganic compounds'
Inorganic compounds do not contain carbon (with the exception of CO2 and CO).
Examples are water, salts, and some acids and bases.
22 of 24
What are the properties that make water vital in the body?
High heat capacity - prevents sudden changes in body temperature.
Polarity/solvent properties - small reactive chemicals can dissolve easily and become evenly distributed.
Chemical reactivity - an important reactant.
Cushioning - cerebrospinal fluid.
23 of 24
Define 'organic compounds'
Organic compounds contain carbon, and are large, covalent molecules.
Examples are carbohydrates, lipids, proteins, and nucleic acids.
24 of 24
Other cards in this set
Card 2
Front
Define energy
Back
Energy is the ability to do work or to move matter.
It has no mass and doesn't occupy space. It can only be measured by it's effects on matter.
Comments
No comments have yet been made