viernes, 12 de abril de 2013


Examples of Chemical and chemical changes:
http://www.youtube.com/watch?v=X328AWaJXvI

Law of conservation of mass: States that ordinary chemical and physical changes, mass is not created or destroyed but is only transformed into different substances


How can matter be classified?

Atoms are the smallest unit of an element that maintains the properties of that element
The substances can be classified into one of the three major classes of matter: elements, compounds and mixtures.
An element is made up of one or more of the same kind of atom chemically combined.
A compound is made up of different kinds of atoms chemically combined. Compounds have different properties from the elements that make them up.
A mixture contains a variety of elements and compounds that are not chemically combinedwith each other.











 What are pure substances?
A pure substance is a substance that has definite physical and chemical properties such as melting point, appearance and reactivity.Elements and compounds are pure substances.


How can compounds be classified?
By their pH
As Organic and Inorganic
By their role in the body

What are mixtures?
 Are a combination of two or more substances that are combined physically but not chemically. They  are classified in:
Heterogeneous: mixture is one that doesnt have a uniform composition.
Homogeneous: is a mixture that has a uniform composition.

Examples of Chemical and chemical changes:
http://www.youtube.com/watch?v=X328AWaJXvI

Law of conservation of mass: States that ordinary chemical and physical changes, mass is not created or destroyed but is only transformed into different substances

viernes, 15 de marzo de 2013

Volume: The amount of space that an object takes up or occupies.














Also volume is determine by using a formula for  regular shaped object and irregular shaped object using a graduated cylinder with water inside it.             








  
 The formula is: Length* width* heigth..

Density: Is the measure of the amount of mass in a given volume.The formula for density is mass/ volume.




Physical and chemicals changes 

Examples:

Physical changes: A characteristic of a substance that can be observed and measured without changing the the identity of the substance.


 Electrical conductivity: the measure of how well and electrical current can move thruogh a substance.

Solubility: ability of a substance to dissolve in an other substance
malleability.

Malleability: the ability of a substance to be rolled or pounded into various shapes.



Chemical Changes: describe a substances ability to change into a new substance with different properties. 

  Flammability: The ability of a substance to burn.
    Reactivity: Is the ability of a substance to interact with another substance and form a new one