Matter Notes

Matter

and

Change

Chemistry, it’s all about matter!• Matter is anything that has volume and

mass.

• Examples of Matter:– Earth, air, water, books, people, etc.

• NOT MATTER:– Light, heat, radio waves, magnetic fields

Properties of Matter

• Focuses on the behavior and composition of matter

• Mass

• Color

• State (solid, liquid, gas)

• Ability to dissolve in water

• Conducts electricity

The Macroscopic View of Matter• Matter that is large enough to

be seen

• This is the beginning for all of our observations.

• We can get hints of what matter is made up of by these types of observations …..

• but we need to look closer (smaller) to see the real structure and behavior

The Submicroscopic View

• You can’t even see this with the most powerful microscopes.

• ATOMS!

• This is where the majority of our study of chemistry is!

• This is why we use …

Models in Chemistry

• Because we can’t see the submicroscopic matter, we use models as a representation.

• There are models of what we think atoms look like and of how we think they behave.

• Scientific models are like model airplanes or cars, but these models have been tested and experimentally verified.

The Composition of Matter

• Qualitative – uses words of descriptions– Color– Heat– Texture

• Quantitative – uses numbers and data – Temperature– Length– Mass– Volume

Types of MatterPure Substances – are made of only one type of matter– Elements

• Sodium• Potassium• Chlorine

– Compounds • Sugar• Salt• Water

Mixtures

• A physical blend of two or more components that are NOT in a fixed proportion

• Examples:– Iced tea– Salt water– Pizza– Salad

Pure Substances

Compounds• Two or more

elements chemically combined

• Has different properties than the individual elements

• NaCl – table salt

Elements•The building blocks of matter•The simplest form of matter•90 elements are naturally occurring•Fewer than half the elements are abundant enough to play a significant role in chemistry.

• Elements are organized on the periodic table.

• Element symbols are used to represent elements.– Ag: Silver– H: Hydrogen

• Formulas are combinations of chemical symbols and their amounts, used to represent compounds.– H2O: Water

– Fe2O3: Iron (III) Oxide (rust)

Types of Mixtures

• Heterogeneous – composition is NOT uniform (pizza, salad, water and oil)

•Homogeneous – composition is uniform (Kool-Aid, motor oil)

Homogeneous Solutions

• Gas/Gas – air (oxygen and nitrogen)• Liquid/Gas – soda (water and carbon

dioxide)• Liquid/Liquid – vinegar (water and acetic

acid)• Liquid/Solid – salt water (water and salt)• Solid/Liquid – sponge (sponge and water)• Solid/Solid – stainless steel (iron,

chromium, and nickel) – Alloy – metal solution

Parts of a Solution

• Solute – the substance being dissolved, present in a smaller quantity

• Solvent – substance doing the dissolving, present in a larger quantity

Aqueous Solution

• A solution in which the solvent is water

Physical Changes

• Alters the properties of the material without changing the composition

• Phase changes – boil, freeze, melt, condense

• Dissolve, cut, grind, bend, break split, crack, crush

States of Matter

• Solid

• Liquid

• Gas

• Plasma

(ionized gas)

Changes in State• Freezing – from a liquid to a solid

• Melting – from a solid to a liquid

• Evaporation – from a liquid to a gas

• Condensation – from a gas to a liquid

Physical Properties

• Properties of materials that can be observed without altering the material.

• We use these to separate mixtures.

• Solubility, melting point, boiling point, color, density, electrical conductivity, state (solid, liquid, or gas)

Volatility

• A volatile substance changes from a liquid to a gas at room temperature.

• Gasoline

• Alcohol

Chemical Properties

• Properties of materials that can only be observed when the substance changes composition

• Cannot be reversed without a chemical reaction

• Rusting, Flammability

Chemical Changes• Alters the composition of

the substance

• Creates a new substance

• Cannot be reversed without another chemical reaction– Burning paper produces soot,

carbon dioxide, and water vapor

– Combining and acid and a base forms water

Summary

Matter

Mixtures Pure Substances

Hetero. Homo. Elements Compounds

Physical Changes Chemical Changes

Density

• The ratio of the mass of an object to its volume

• Mass/volume (g/mL or g/cm3)• Density of water = 1 g/mL• Less dense objects float, more dense

objects sink• Increasing temperature decreases density

(hot air rises)

Manipulating the Density Equation

• D = m/v

• m = Dv

• v = m/D

A bar of silver has a mass of 68.0 g and a volume of 6.48 mL. What is the density of silver?

D = m/v

68.0 g / 6.48 mL

D = 10.5 g/mL

A copper penny has a mass of 3.1 g and a volume of 0.35 mL. What is the density of copper?

D = m/v

3.1 g / 0.35 mL

D = 8.9 g/mL

Signs of a Reaction:

• Gas formation (bubbles, fizzing)

• Color change

• Energy (heat/light released or absorbed)

• Precipitate formation – solid settling out of a liquid

Law of Conservation of Mass

• During any chemical reaction, mass is neither created nor destroyed, it is conserved

the mass of the products (what is made from the reaction)

the mass of the reactants (what goes into a reaction)

Energy in Reactions

• Exothermic– Reaction gives off heat– Feels hot– Hand warmers

• Endothermic– Reaction absorbs heat– Feels cold– Ice packs

the capacity to do work; often observed as heat or light