CHEM Topic 2 Lecture

Classification of Matter

Matter is anything that has mass and volume. It exists in different states: solid, liquid, and gas. A fourth state, plasma, also exists.

States of Matter

1. Solid:

   • Atoms have a repeating geometric structure.

   • Atoms vibrate in place.

   • Most dense state (except for water).

   • Crystalline pattern.

   • Atoms are still moving unless they're at absolute zero (-273 degrees Celsius).

   • Amorphous solids, like plastics, exist.

2. Liquid:

   • Atoms can slip past one another.

   • Takes on the shape of its container but has a fixed volume.

   • Atoms are attracted enough to each other that they don't break free.

   • Water is an exception, as it is most dense as a liquid, and ice floats because it's less dense.

3. Gas:

   • Atoms overcome attractive forces and spread as far apart as possible.

   • Have no attraction for one another, so they fly off in different directions.

   • The mass of a gas is much less than in solid or liquid states.

Changes in State

• Sublimation: Solid changes directly into a gas (e.g., dry ice, iodine )

• Deposition: Gas changes directly into a solid (e.g., frost/snow).

Heating Curve

Imagine taking ice and putting it on a hot plate. As heat is added:

• The ice melts (fusion).

• The water boils.

• Kinetic energy increases with added heat, potentially leading to a gaseous state.

• Temperature remains constant during phase changes (melting or boiling).

• Different substances require different temperatures for these changes. Understanding the specific heat capacities of these substances can aid in predicting the temperatures at which they will change phases.

Sublimation Example

• Pure iodine is a purple crystal.

• Under the right conditions, almost any molecule can be forced to sublimate.

• Skipping the liquid phase is a common feature of sublimation.

• Heat is added to the material during sublimation.

Deposition Example

• Water clouds are liquid water droplets in the atmosphere.

Classification of Matter

• Pure Substances: Cannot be separated by physical means.

  • Elements: Composed of identical atoms (e.g., aluminum, oxygen, carbon). Represented on the periodic table.

  • Compounds: Composed of two or more different atoms chemically bonded in the same proportions (e.g., water (H2O), ammonia (NH3). Can only be separated by chemical reactions.

• Mixtures: Two or more elements/compounds physically combined and can be separated by physical means.

  • Heterogeneous mixtures: Different components can be visually differentiated and separated by filtration (e.g., orange juice with pulp). You can typically see more than one thing present just by looking at it.

  • Homogeneous mixtures: Uniform throughout and separated by methods like boiling (e.g., saltwater, Kool-Aid). Have the same consistency throughout.

Key Concepts

• Element: One kind of atom; the name of a kind of atom.

• Compound: Always has the same proportions.

• Decomposition: To separate hydrogen from oxygen in a water molecule requires a chemical reaction.

Brinklehoffs

Elements that always travel in pairs:

• Bromine (Br_2)

• Iodine (I_2)

• Nitrogen (N_2)

• Chlorine (Cl_2)

• Hydrogen (H_2)

• Oxygen (O_2)

• Fluorine (F_2)

These are not considered compounds.

Abundance of Elements

• A lot of hydrogen and oxygen in the US because of water.

• A large amount of oxygen in the earth's crust because a lot of minerals have oxygen chemically bonded in them.

Separating Matter

Different methods:

• Filtration

• Distillation

• Chemical reaction (Decomposition)

Examples of Classification

1. Helium: Element

2. Whole milk: Heterogeneous mixture (separate with a centrifuge)

3. Air: Homogeneous mixture (solution)

4. Sugar (sucrose): Compound

5. Propane: Compound

6. Iron: Element

7. Steel: Homogeneous mixture (mixture of iron and carbon)

8. Blood: Heterogeneous mixture (has different components that can be centrifuged out)

Physical and Chemical Properties

• Physical properties: Properties unrelated to chemical reactions (e.g., density, color, boiling point, physical states).

• Chemical properties: How a substance chemically reacts with other substances (e.g., flammability, oxidation).

Examples

• Boiling and melting are physical changes (altering the state of the material).

• Burning something is a chemical change (converting organic material into carbon dioxide and water vapor).

Classification of Matter

Matter is anything that has mass and volume. It exists in different states: solid, liquid, and gas. A fourth state, plasma, also exists. Think of it like this: matter is the "stuff" around you, whether it's the chair you're sitting on, the water you drink, or the air you breathe!

States of Matter

1. Solid:

   • Imagine atoms packed tightly together in a repeating geometric pattern. They're like little soldiers standing in formation.

   • Atoms vibrate in place; they don't move around.

   • Usually the most dense state (meaning it packs the most "stuff" into a space) – except for water, which is weird!

   • Crystalline pattern (think of salt or sugar crystals).

   • Atoms are still jiggling unless they're at absolute zero (-273 degrees Celsius), which is super cold!

   • Amorphous solids, like plastics, don't have a crystal structure.

2. Liquid:

   • Atoms can slip and slide past one another like marbles in a bag.

   • Liquids take the shape of their container but have a fixed volume. Pour water into a glass, and it fills the glass, but it's still the same amount of water.

   • Atoms are attracted enough to each other that they don't break free.

   • Water is special: it's most dense as a liquid. Ice floats because it's less dense.

3. Gas:

   • Atoms are like tiny explorers who have overcome attractive forces and spread out as far as possible.

   • Gases have no strong attraction for one another.

   • The mass of a gas is much less than the mass of the same substance in solid or liquid form.

Changes in State

• Sublimation: Solid turns directly into a gas. Think of dry ice (CO2) disappearing in front of your eyes or iodine (I2) crystals releasing a purple vapor.

• Deposition: Gas turns directly into a solid, like frost or snow forming on a cold day.

Heating Curve

Imagine putting ice on a stove. What happens?

• The ice melts (fusion).

• The water boils.

• Kinetic energy (the energy of motion) increases with added heat.

• Temperature stays still during phase changes (melting or boiling), like the water's taking a break at 100 degrees celsius while it is boiling.

• Different substances change at different temperatures.

• H2O(s) \rightarrow H2O(g)

Sublimation Example

• Pure iodine is a cool purple crystal.

• Almost any molecule can sublimate if conditions are right.

• Skipping the liquid phase is normal during sublimation.

• Heat is added during sublimation.

Deposition Example

• Water clouds are actually liquid droplets.

Classification of Matter

• Pure Substances: Cannot be separated by physical means.

  • Elements: Contain identical atoms (e.g., aluminum, oxygen, carbon). You can find them on the periodic table.

  • Compounds: Contain two or more different atoms chemically bonded in fixed proportions (e.g., water (H2O), ammonia (NH3)).

• Mixtures: Have two or more elements/compounds physically combined, and can be separated by physical means.

  • Heterogeneous mixtures: Different parts appear clearly (e.g., orange juice with pulp).

  • Homogeneous mixtures: Uniform throughout (e.g., saltwater, Kool-Aid).

Key Concepts

• Element: One kind of atom; the element's name is the name of the kind of atom the element is comprised of.

• Compound: Always has the same element proportions.

• Decomposition: Is needed to separate hydrogen from oxygen.

Brinklehoffs

Elements that always travel in pairs. Remember "Brinklehoffs are diatomic":

• Bromine (Br_2)

• Iodine (I_2)

• Nitrogen (N_2)

• Chlorine (Cl_2)

• Hydrogen (H_2)

• Oxygen (O_2)

• Fluorine (F_2)

These are not compounds; they're just elements sticking together!

Abundance of Elements

• A lot of hydrogen and oxygen in the US because of water.

• Oxygen in Earth's crust is abundant because it is chemically bonded to minerals.

Separating Matter

Different methods:

• Filtration

• Distillation

• Chemical reaction (Decomposition)

Examples of Classification

1. Helium: Element

2. Whole milk: Heterogeneous mixture (separate with a centrifuge)

3. Air: Homogeneous mixture (solution)

4. Sugar (sucrose): Compound (C{12}H{22}O_{11})

5. Propane: Compound

6. Iron: Element

7. Steel: Homogeneous mixture (mixture of iron and carbon)

8. Blood: Heterogeneous mixture (separate using a centrifuge)

Physical and Chemical Properties

• Physical properties: Properties unrelated to chemical reactions (e.g., density, color, boiling point, physical states).

• Chemical properties: How a substance reacts (e.g., flammability, oxidation).

Examples

• Boiling and melting are physical changes (altering the state of the material).

• Burning something is a chemical change (converting organic material into carbon dioxide and water vapor).

Classification of Matter

Matter is anything that has mass and volume. It exists in different states: solid, liquid, and gas. A fourth state, plasma, also exists. Think of it like this: matter is the "stuff" around you, whether it's the chair you're sitting on, the water you drink, or the air you breathe!

States of Matter

1. Solid:

   • Imagine atoms packed tightly together in a repeating geometric pattern. They're like little soldiers standing in formation.

   • Atoms vibrate in place; they don't move around.

   • Usually the most dense state (meaning it packs the most "stuff" into a space) – except for water, which is weird!

   • Crystalline pattern (think of salt or sugar crystals).

   • Atoms are still jiggling unless they're at absolute zero (-273 degrees Celsius), which is super cold!

   • Amorphous solids, like plastics, don't have a crystal structure.

2. Liquid:

   • Atoms can slip and slide past one another like marbles in a bag.

   • Liquids take the shape of their container but have a fixed volume. Pour water into a glass, and it fills the glass, but it's still the same amount of water.

   • Atoms are attracted enough to each other that they don't break free.

   • Water is special: it's most dense as a liquid. Ice floats because it's less dense.

3. Gas:

   • Atoms are like tiny explorers who have overcome attractive forces and spread out as far as possible.

   • Gases have no strong attraction for one another.

   • The mass of a gas is much less than the mass of the same substance in solid or liquid form.

Changes in State

• Sublimation: Solid turns directly into a gas. Think of dry ice (CO2) disappearing in front of your eyes or iodine (I2) crystals releasing a purple vapor.

• Deposition: Gas turns directly into a solid, like frost or snow forming on a cold day.

Heating Curve

Imagine putting ice on a stove. What happens?

• The ice melts (fusion).

• The water boils.

• Kinetic energy (the energy of motion) increases with added heat.

• Temperature stays still during phase changes (melting or boiling), like the water's taking a break at 100 degrees celsius while it is boiling.

• Different substances change at different temperatures.

• H2O(s) \rightarrow H2O(g)

Sublimation Example

• Pure iodine is a cool purple crystal.

• Almost any molecule can sublimate if conditions are right.

• Skipping the liquid phase is normal during sublimation.

• Heat is added during sublimation.

Deposition Example

• Water clouds are actually liquid droplets.

Classification of Matter

• Pure Substances: Cannot be separated by physical means.

  • Elements: Contain identical atoms (e.g., aluminum, oxygen, carbon). You can find them on the periodic table.

  • Compounds: Contain two or more different atoms chemically bonded in fixed proportions (e.g., water (H2O), ammonia (NH3)).

• Mixtures: Have two or more elements/compounds physically combined, and can be separated by physical means.

  • Heterogeneous mixtures: Different parts appear clearly (e.g., orange juice with pulp).

  • Homogeneous mixtures: Uniform throughout (e.g., saltwater, Kool-Aid).

Key Concepts

• Element: One kind of atom; the element's name is the name of the kind of atom the element is comprised of.

• Compound: Always has the same element proportions.

• Decomposition: Is needed to separate hydrogen from oxygen.

Brinklehoffs

Elements that always travel in pairs. Remember "Brinklehoffs are diatomic":

• Bromine (Br_2)

• Iodine (I_2)

• Nitrogen (N_2)

• Chlorine (Cl_2)

• Hydrogen (H_2)

• Oxygen (O_2)

• Fluorine (F_2)

These are not compounds; they're just elements sticking together!

Abundance of Elements

• A lot of hydrogen and oxygen in the US because of water.

• Oxygen in Earth's crust is abundant because it is chemically bonded to minerals.

Separating Matter

Different methods:

• Filtration

• Distillation

• Chemical reaction (Decomposition)

Examples of Classification

1. Helium: Element

2. Whole milk: Heterogeneous mixture (separate with a centrifuge)

3. Air: Homogeneous mixture (solution)

4. Sugar (sucrose): Compound (C{12}H{22}O_{11})

5. Propane: Compound

6. Iron: Element

7. Steel: Homogeneous mixture (mixture of iron and carbon)

8. Blood: Heterogeneous mixture (separate using a centrifuge)

Physical and Chemical Properties

• Physical properties: Properties unrelated to chemical reactions (e.g., density, color, boiling point, physical states).

• Chemical properties: How a substance reacts (e.g., flammability, oxidation).

Examples

• Boiling and melting are physical changes (altering the state of the material).

• Burning something is a chemical change (converting organic material into carbon dioxide and water vapor).

Classification of Matter

Matter is anything that has mass and volume. It exists in different states: solid, liquid, and gas. A fourth state, plasma, also exists. Think of it like this: matter is the "stuff" around you, whether it's the chair you're sitting on, the water you drink, or the air you breathe!

States of Matter

1. Solid:

   • Imagine atoms packed tightly together in a repeating geometric pattern. They're like little soldiers standing in formation.

   • Atoms vibrate in place; they don't move around.

   • Usually the most dense state (meaning it packs the most "stuff" into a space) – except for water, which is weird!

   • Crystalline pattern (think of salt or sugar crystals).

   • Atoms are still jiggling unless they're at absolute zero (-273 degrees Celsius), which is super cold!

   • Amorphous solids, like plastics, don't have a crystal structure.

2. Liquid:

   • Atoms can slip and slide past one another like marbles in a bag.

   • Liquids take the shape of their container but have a fixed volume. Pour water into a glass, and it fills the glass, but it's still the same amount of water.

   • Atoms are attracted enough to each other that they don't break free.

   • Water is special: it's most dense as a liquid. Ice floats because it's less dense.

3. Gas:

   • Atoms are like tiny explorers who have overcome attractive forces and spread out as far as possible.

   • Gases have no strong attraction for one another.

   • The mass of a gas is much less than the mass of the same substance in solid or liquid form.

Changes in State

• Sublimation: Solid turns directly into a gas. Think of dry ice.

• Deposition: Gas turns directly into a solid, like frost or snow forming on a cold day.

Heating Curve

Imagine putting ice on a stove. What happens?

• The ice melts (fusion).

• The water boils.

• Kinetic energy (the energy of motion) increases with added heat.

• Temperature stays still during phase changes (melting or boiling), like the water's taking a break at 100 degrees celsius while it is boiling.

• Different substances change at different temperatures.

Sublimation Example

• Pure iodine is a cool purple crystal.

• Almost any molecule can sublimate if conditions are right.

• Skipping the liquid phase is normal during sublimation.

• Heat is added during sublimation.

Deposition Example

• Water clouds are actually liquid droplets.

Classification of Matter

• Pure Substances: Cannot be separated by physical means.

  • Elements: Contain identical atoms (e.g., aluminum, oxygen, carbon). You can find them on the periodic table.

  • Compounds: Contain two or more different atoms chemically bonded in fixed proportions (e.g., water (H2O), ammonia ( NH3).

• Mixtures: Have two or more elements/compounds physically combined, and can be separated by physical means.

  • Heterogeneous mixtures: Different parts appear clearly (e.g., orange juice with pulp).

  • Homogeneous mixtures: Uniform throughout (e.g., saltwater, Kool-Aid).

Key Concepts

• Element: One kind of atom; the element's name is the name of the kind of atom the element is comprised of.

• Compound: Always has the same element proportions.

• Decomposition: Is needed to separate hydrogen from oxygen.

Brinklehoffs

Elements that always travel in pairs. Remember "Brinklehoffs are diatomic":

• Bromine (Br_2)

• Iodine (I_2)

• Nitrogen (N_2)

• Chlorine (Cl_2)

• Hydrogen (H_2)

• Oxygen (O_2)

• Fluorine (F_2)

These are not compounds; they're just elements sticking together!

Abundance of Elements

• A lot of hydrogen and oxygen in the US because of water.

• Oxygen in Earth's crust is abundant because it is chemically bonded to minerals.

Separating Matter

Different methods:

• Filtration

• Distillation

• Chemical reaction (Decomposition)

Examples of Classification

1. Helium: Element

2. Whole milk: Heterogeneous mixture (separate with a centrifuge)

3. Air: Homogeneous mixture (solution)

4. Sugar (sucrose): Compound

5. Propane: Compound

6. Iron: Element

7. Steel: Homogeneous mixture (mixture of iron and carbon)

8. Blood: Heterogeneous mixture (separate using a centrifuge)

Physical and Chemical Properties

• Physical properties: Properties unrelated to chemical reactions (e.g., density, color, boiling point, physical states).

• Chemical properties: How a substance reacts (e.g., flammability, oxidation).

Examples

• Boiling and melting are physical changes (altering the state of the material).

• Burning something is a chemical change (converting organic material into carbon dioxide and water vapor).