Chapter 4- The chemistry of life (1) Flashcards
How is matter moved around?
By energy
Matter can exist in three states:
Solids, liquids, and gases
What are the properties of a solid, liquid and gas?
Solid has a definite shape and volume- examples are bones, teeth
Liquid has a definite volume, but they can flow and fill any space- examples include blood plasma
Gases have no defined shape or volume- example is air
What is energy?
The ability to put matter into motion
Energy comes in two main types:
1- Kinetic energy- is that which moves things
2- Potential energy- is stored energy. It is inactive energy that has potential to do work. When the energy is released, it becomes kinetic energy
What are other main types of energy
1- Chemical energy- stored in chemical bonds. Chemical reactions rearrange atoms.
2- Electrical energy- movement of charged particles (ions). The ions move along cell membranes.
3- Mechanical energy- Energy directly involved in moving matter
4- Radiant energy (electromagnetic radiation) - energy that travels in waves
ENERGY CAN NEITHER
BE CREATED OR DESTROYED
4 elements make up most of our body weight. What are they?
1- Carbon
2- Oxygen
3- Hydrogen
4- Nitrogen
Every element is made from an…
Atom
What does the structure of an atom contain?
Protons
Neutrons
Electrons
The protons and neutrons make up what part of the atom?
The nucleus
What charge does the nucleus have?
A positive charge
Why are atoms electrically neutral?
Because an atom will have the same number of protons and electrons
What is an isotope?
Forms of the same element that have the same number of protons and electrons but a different number of neutrons.
What are radioisotopes?
Isotopes that have more neutrons in the nucleus than protons and electrons. This is seen as unstable.
Why are radioisotopes dangerous?
Because they are radioactive which means they can spontaneously decompose to form unstable atoms.
How do radioisotopes spontaneously decompose?
Through atomic decay
What are the types of energy that are released during atomic decay?
1- Alpha particles
2- Beta particles
3- Gamma rays
Molecules can be of two types. What are they?
1- Molecules of an element- when atoms of the same element combine, e.g, H2
2- Molecules of a compound- when different kinds of atom combine, e.g, H2O
What is a mixture?
A mixture is when two or more components are physically intermixed.
What are the 3 types of mixtures?
1- Solutions- where solute particles are very tiny, e.g., water
2- Colloids- this is where solute particles are larger than in a solution, e.g., jelly
3- Suspensions- this is where solute particles are very large, e.g., blood
Is there chemical bonding between components of a mixture?
No
How can mixtures be separated physically?
1- Straining
2- Evaporating
3- Filtering
Compounds need what type of bonds to be broken in order to separate?
Chemical bonds
Are mixtures heterogenous or homogenous?
Both
