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Topic 1.1. Nature of Matter

Essential Idea: Physical and chemical properties depend on the ways in which different atoms combine.

Nature Of Science: Making quantitative measurements with replicates to ensure reliability – definite and multiple proportions. (3.1)

Understandings :

1) Atoms of different elements combine in fixed ratios to form compounds, which have different properties from their component elements.

2) Mixtures contain more than one element and/or compound tat are not chemically bonded together and so retain individual properties.

3) Mixtures are either homogenous or heterogeneous.

Nature of Matter. 1.1

Applications and Skills:1) Deduction of chemical equations when reactants and products are specified.

2) Application of the state symbols (s), (l), (g), (aq)

3) Explanation of observable changes in physical properties and temperature during changes of state.

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Nature of Matter. 1.1

Guidance:– 1) Names of the changes of state: melting,

freezing, vaporization (evaporation and boiling), condensation, sublimation, and deposition-should be covered.

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MATTER

Matter = anything that has mass and takes up space

Atoms are the smallest unit of matter

Don’t trust anything an atom says… They make up everything.

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Distinguish between physical and chemical properties

Physical property

A characteristic of a substance that can be measured or observed without changing the substance’s composition

Chemical property The ability of a substance to

undergo a chemical reaction to form new substances

Distinguish between physical and chemical properties

Examples of Physical Properties

Color Solubility (Dissolving) Odor Hardness Density Melting Point Boiling Point State of matter Thermal capacity

Examples of Chemical Properties

Reactivity with oxygen Reactivity with acids Reactivity with bases

Sodium and Chlorine Reaction

Distinguish between physical and chemical properties

Sodium is a silver metal at room conditions; combines with chlorine to make table salt; reacts with water to form hydrogen; has a density of 0.93 g/cm3; oxidizes rapidly in air, melts at 97.8oC.

Using the above description, list the physical properties of sodium

Using the above description, list the chemical properties of sodium

Distinguish between physical and chemical properties

Sodium is a silver metal at room conditions; combines with chlorine to make table salt; reacts with water to form hydrogen; has a density of 0.93 g/cm3; oxidizes rapidly in air, melts at 97.8oC.

Using the above description, list the physical properties of sodium

Using the above description, list the chemical properties of sodium

Physical & Chemical Property HO

Distinguish between physical and chemical changes

Physical change

An alteration of matter that does not change the chemical composition of the material.

Chemical change Results in a change in the

chemical composition of the substance(s). This is called a reaction.

Distinguish between physical and chemical changes

How to tell a chemical reaction has occurred:– Heat is absorbed or given off– Change in color – Change in odor– Production of a gas or solid

Do not confuse liquid water turning into steam as a chemical change!!! Water particles are still H2O in both states of matter

– Change in pH– Not easily reversible (it won’t recreate the reactants)

Distinguish between physical and chemical changes

Examples of Physical Changes

Freezing or melting Boiling or condensing Cutting Grinding Bending Blending Dissolving

Examples of Chemical Changes

Combustion (burning) Reacts with an acid Reacts with a base Rusting Oxidizing Decomposing Digesting

Distinguish between physical and chemical changes Copy the statement on your paper and write P for physical or C for chemical

1. Bending of a piece of wire

2. Burning of coal

3. Cooking a steak

4. Cutting grass

5. Sodium reacts with water

6. Iron rusts7. Silicon is insoluble in

water8. Ice melts9. Neon boils at -2460C10. Nitric Acid reacts

with Copper

Pass out Handout

States of Matter

State Shape VolumeExpansion

when heatingCompressibility

Solid (S) Fixed Fixed Very slightlyAlmost

incompressible

Liquid (l)

Aqueous

(aq)Indefinite Fixed Moderate

Almost Incompressible

Gas or Vapor (g)

Indefinite Indefinite GreatReadily

compressible

Distinguish between elements, compounds, and mixtures

Elements are composed of just one type of atom. They cannot be separated into simpler substances using chemical means.

Compounds are substances composed of two or more different kinds of atoms that have combined chemically. They can be separated by chemical means.

Mixtures contain more than one element and/or compound that are not chemically bonded together and so retain individual properties.

Distinguish between elements, compounds, and mixtures

Elements– Represented by a chemical symbol (see Periodic

Table)– Gold (Au), Iron (Fe), Oxygen (O or O2)

Distinguish between elements, compounds, and mixtures

Compounds– Represented by a chemical

formula that shows the elements and relative number of atoms in the compound.

– Examples: Water, H2O, contains 2 atoms of

hydrogen (H) and one atom of oxygen(O).

Salt, NaCl, contains one atom of sodium (Na) for each atom of chlorine (Cl).

Distinguish between elements, compounds, and mixtures

Mixtures: Heterogeneous mixture – One that is not uniform in

composition and appearance.– Ex: chicken noodle soup, concrete, granite

Homogeneous mixture- One that is uniform in composition, also called solutions.– Ex: clean air, distilled water, syrup

Pass out Mixture Handout

Distinguish between elements, compounds, and mixtures

Ways to separate mixtures:– Heterogeneous: sieving, tweezers, skimming

– Homogeneous: distillation, ion exchange, reverse osmosis

Distinguish between elements, compounds, and mixtures

1. Blood2. Hydrogen3. Brass (copper and zinc)

4. Ice5. Motor oil

6. Silver

7. Orange juice

8. Neon

9. Sugar

10. Lake waterPass Out Handout

Copy the item and indicate if it is an element, compound or mixture.

Distinguish between physical and chemical changes

In a chemical reaction, one or more substances change into new substances by rearranging the atoms

Reactants Products

Copper+ nitric acid copper(II) nitrate+ nitrogen dioxide+water

Distinguish between physical and chemical changes

How to tell a chemical reaction has occurred:– Heat is absorbed or given off– Change in color – Change in odor– Production of a gas or solid

Do not confuse liquid water turning into steam as a chemical change!!! Water particles are still H2O in both states of matter

– Change in pH– Not easily reversible (it won’t recreate the reactants)

Distinguish between physical and chemical changes

Law of Conservation of Mass– During any chemical reaction, mass

is neither created nor destroyed, it is conserved.

– The mass of the products will always equal the mass of the reactants.

– The mass of each element is also unchanged.

Distinguish between physical and chemical changes

Law of Conservation of MassIn the reaction where hydrogen reacted

with oxygen to produce water; if 4.5 grams of hydrogen and 34 grams of oxygen were used, how many grams of water was produced?

Hydrogen + oxygen water

4.5g + 34g = 38.5g water