Physical ScienceChemical Properties

Atoms and MoleculesAn Atom is made up of protons, electrons, and neutrons.

An Element is a unique number of protons.

When 2 or more atoms combine together chemically, it is called a molecule.

Molecular Elements

These are allotropes of carbon

Compounds

2 or more elements combined in a molecule

What is a Chemical Reaction?

It is the rearrangement of atoms to form new molecules.

CH4 + 2O2 CO2 + 2H2O

What is a Chemical Reaction?

It is the rearrangement of atoms to form new molecules.

CH4 + 2O2 CO2 + 2H2O

What is a Chemical Reaction?

It is the rearrangement of atoms to form new molecules.

CH4 + 2O2 CO2 + 2H2O

What is a Chemical Reaction?

Some chemical reactions are exothermic

They release energy as heat, light, or other forms.

What is a Chemical Reaction?

Some chemical reactions are endothermic

They absorb energy from the environment to proceed.

Chemical Properties

Chemical properties can only be observed when the substances in a sample of matter are ________________.

_____ and _____ are examples of chemical properties

Chemical Properties

Chemical properties can only be observed when the substances in a sample of matter are ________________. Changing into different substances

_____ and _____ are examples of chemical properties

Chemical Properties

Chemical properties can only be observed when the substances in a sample of matter are ________________. Changing into different substances

_____ and _____ are examples of chemical properties Flammability Reactivity

Triggers to Chemical Reactions

Most reactions do not occur spontaneously.

Most require some trigger to get started.

This could be a spark or even a touch.

Let’s watch a fun video of a chemical reaction that is sensitive to the touch!

Nitrogen Triiodide2 NI3 (s) → N2 (g) + 3 I2 (g),

Nitrogen Triiodide Decomposition

Some Fun Experiments

Mr. Taylor Does Nitrogen Triiodide

http://www.youtube.com/watch?v=hERVtZEZrFQ

Some Fun Experiments

http://www.youtube.com/watch?v=sjLgzgflCk8

THERMITE!

Some Fun Experiments

Pure Metallic Sodium in Water!

http://www.youtube.com/watch?v=gFnNXkcoDSs

Recognizing Chemical Change

Chemical changes are taking place if you see a _____, ______, or ______. Change in color Production of a gas Formation of a precipitate

**If you are watching by recording, send me the sentence above with the answers**

MixturesIron and Sulfur powder in a the mixture

So, it is hypothesis time:

How can we separate the iron from the sulfur?

Enter some ideas in the chat box.

Mixtures

Iron and sulphur – the mixture

How can we separate the iron from the sulphur?

Use a magnet!

Iron is magnetic, sulfur is not...

Turning an iron-sulphur mixture into a Compound

Fe + S FeS Heat

When iron and sulphur react

+sulphur (S) atoms iron (Fe) atoms

When iron and sulphur react

+sulphur (S) atoms iron (Fe) atoms

iron sulphide (FeS) molecules

Differences between compounds and mixtures

MIXTURES COMPOUNDS

1. Mixtures can be separated easily

1. Compounds can not be separated

Differences between compounds and mixtures

MIXTURES COMPOUNDS

1. Mixtures can be separated easily

2. Mixture have the properties of the substances present in it

1. Compounds can not be separated

2. Compounds do not have the properties of the elements

Differences between compounds and mixtures

MIXTURES COMPOUNDS

1. Mixtures can be separated easily

2. Mixture have the properties of the substances present in it

3. No chemical change takes place when a mixture is made

1. Compounds can not be separated

2. Compounds do not have the properties of the elements

3. A compound is always formed due to a chemical reaction

Differences between compounds and mixtures

MIXTURES COMPOUNDS

1. Mixtures can be separated easily

2. Mixture have the properties of the substances present in it

3. No chemical change takes place when a mixture is made

4. There is no heat taken in or given out when a mixture is made

1. Compounds can not be separated

2. Compounds do not have the properties of the elements

3. A compound is always formed due to a chemical reaction

4. Heat is either taken in or given out when a compound is made

Differences between compounds and mixtures

MIXTURES COMPOUNDS

1. Mixtures can be separated easily

2. Mixture have the properties of the substances present in it

3. No chemical change takes place when a mixture is made

4. There is no heat taken in or given out when a mixture is made

5. A mixture can contain elements in any proportion

1. Compounds can not be separated

2. Compounds do not have the properties of the elements

3. A compound is always formed due to a chemical reaction

4. Heat is either taken in or given out when a compound is made

5. A compound always contains the elements in fixed proportions, e.g. FeS contains 7g of iron to 4g of sulphur