Chapter 2Matter & Change

Standards: INQB, Matter consists of atoms that have internal structures that dictate their chemical and physical behavior.

Targets:• Distinguish between physical and chemical properties• Distinguish between physical and chemical changes• Distinguish between elements, compounds, and mixtures

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• Mass

Examples of Chemical Properties

• Reactivity with oxygen • Reactivity with acids• Reactivity with bases• Reactivity with other

elements

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

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

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

States of Matter

State Shape VolumeExpansion

when heatingCompressibility

Solid (S)

Definite Definite Very slightlyAlmost

incompressible

Liquid (l)

Indefinite Definite ModerateAlmost

Incompressible

Gas or Vapor

(g)Indefinite Indefinite Great

Readily 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 are a physical blend of two or more substances. They can be separated by physical means.

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: soup, concrete, granite

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

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

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

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

4. Ice5. Motor oil

6. Silver

7. Orange juice

8. Neon

9. Sugar

10. Lake water

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 or odor.– Production of a gas or solid.– Not easily reversible.

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