General Chemistry 1 (CHM 2045)- Spring 2025 Semester Chapter 1 and 2!

What is chemistry the study of?

Chemistry is the study of matter!

What is matter?

Anything that occupies space and has mass.

What is mass?

Measure of the amount of matter that an object contains.

How can be matter be classified?

According to it’s physical state!

(Ex: Gas, liquid or solid)

What does a solid have?

Fixed Volume and fixed shape

What does a liquid have?

Fixed volume and no definite shape.

What does a gas have?

A gas has neither a fixed volume or fixed shape.

How else can we classify matter?

According to it’s composition. (Ex: Element, Compound or Mixture)

Mixture: Homogeneous and Heterogeneous

What type of composition does a heterogeneous mixture have?

Nonuniform Composition

What type of composition does a homogeneous mixture have?

Uniform Composition Throughout!

How do you know it’s a mixture? (Classifying Matter)

More than one pure substance present. (Composition can be varied.)

Matter can classified as?

A mixture or pure substance.

Mixtures can physically separate into what?

Pure Substances!

How do you know it’s a pure substance?

A fixed composition and it can’t be further purified.

What are pure substances classified as?

Compounds or elements!

Compounds are?

Elements united in fixed ratios!

Compounds are chemically separated into what?

Compounds are chemically separable into their individual elements.

Elements

Can not be subdivided by chemical or physical processes.

Elements combine chemically to form?

Compounds

What can pure substances be?

Elements or compounds

What can compounds be further reduced into?

Compounds can be further reduced into two or more elements!

What do elements consist of?

Elements rather consist of only one type of atom.

(They can’t be decomposed or further simplified by ordinary means.)

Ex: Sodium and Helium

Compounds are a combination of what?

Combination of two or more elements in a definite, reproducible way.

Ex: water (H20) or ammonia (NH3)

Mercury is what?

A liquid at room temperature.

Powdered Sulfur is what?

A solid at room temperature.

Copper Wire is what?

A solid at room temperature.

Iron chips are what?

A solid.

Aluminum is what?

A solid.

Where are the elements recorded?

The Periodic Table!

How many recorded elements are there?

118!

Mixtures

A combination of two or more pure substances.

Mixtures can be further classified as what?

Homogenous - Uniform composition (single phase)

or Heterogeneous - Nonuniform composition

What’s an interesting fact?

When separated, the components of both types of mixtures (homogeneous and heterogeneous) yields pure substances.

What is a synonym for a homogeneous mixture?

Solution

Mixtures can be separated by what?

Physical Properties

How does a compound have to be broken down?

A compound has to be chemically broken down into its elements to go from one pure substance to another.

What are some great examples of physical properties?

Density, Boiling Point, State of Matter, Intermolecular Forces, Vapor Pressure, Magnetism and Solubility.

How does a compound go from one substance to another?

It has to be chemically broken down into it’s elements.

What are some examples of means of separation for physical properties?

Decantation, centrifugation, distillation, filtration, chromatography, evaporation and magnets.

What are some means of separation for density?

Decantation and Centrifugation

What is a means of separation for boiling point?

Distillation

What is a means of separation for state of matter?

Filtration

What is a means of separation for intermolecular forces?

Chromatography

What is a means of separation for vapor pressure?

Evaporation

What is a means of separation for magnetism?

Magnets

What is a means of separation for solubility?

Filtration

Which mixtures can be separated by filtration?

Heterogeneous Mixtures

Which mixture is easier to separate?

Heterogeneous Mixtures

What is an example of separating by filtration?

A heterogeneous mixture of soil and water.

What is an example of separating by filtration?

A heterogeneous mixture of soil and water.

When the mixture is poured through the filter paper, the larger soil particles are trapped and the water passes through.

The water passing through the filter is more pure than the mixture.

Homogeneous Mixtures

Solutions:

Sugar in water

Gasoline

Brass (copper/zinc)

Air

Which mixtures are harder to separate?

Homogeneous Mixtures

Even though homogeneous mixtures are harder to separate what can we use to separate them?

Physical Property

What are examples of homogeneous mixtures solutions?

Sugar in water, gasoline, brass (Mixture of copper/zinc) and air.

What is air?

A mixture of gases.

What is brass a mixture of?

Copper and Zinc

What is a solute?

Minor component of a solution.

What is a solvent?

The substance that contains the solutes.

In a solution what do we classify the two components of a solution?

Solute and Solvent

What does the solvent do?

The dissolving.

What does the solute do?

The solute is being dissolved.

If you want to think about solids going into liquids, what can vary?

Composition of solutions

How do you think about solids going into liquids and their composition of solutions varying?

The way you do that is to change how much solute goes into the solvent.

What happens if you make coffee very very strong versus coffee very, very weak?

It’s a composition or a concentration change.

What are chemical compounds composed of?

Two or more elements

What is a fact about compounds and elements?

Compounds have different properties than the elements.

What is an example of a chemical compound?

A combination of elemental sodium and chlorine gas.

(You create salt crystals or sodium chloride.)

(Sodium chloride is table salt)

What are all compounds made up of?

Molecules or ions.

What is an example of an ionic compound?

Sodium Chloride

What are some examples of molecules?

Water, carbon dioxide, octane and sugar.

What is sugar?

Sugar is a molecule made of carbon, hydrogen, and oxygen atoms.

What are compounds always represented by?

A chemical formula

What do the chemical formula’s of compounds indicate?

It’s a fixed ratio of elements.

EX: H20 (water)

You know it’s a fixed ratio because for every one oxygen atom there are always two hydrogen atoms present.

What do you need to remember about compounds?

Compounds have different properties from their elements!

What else do we know about compounds?

Compounds have a fixed composition ratio (definite proportion)

Compounds also what?

They have a definite % composition by mass.

Text ex: Iron pyrite FeS2 ⮕ 46.55 % iron and 53.45 % sulfur

What is fixed composition ratio?

The specific, unchanging proportion in which elements combine to form a compound. This means that no matter the source of the compound, the ratio of its constituent elements will always be the same

Fixed composition ratio (definite proportion):

DEFINITE % composition by mass

Physical Properties

Characteristics that can be evaluated without changing the composition of the material.

What are examples of physical properties?

Color

Odor

Density

Melting Point

Thermal conductivity

Volume

Hardness

Some physical physical properties:

Color

State (s, g, or liq)

Melting and Boiling point

Density (mass/unit volume)

What are the types of physical properties?

Extensive and Intensive

Intensive Properties:

(density) do not.

Intensive ⮕ independent of sample size

Extensive properties:

(mass) depend upon the amount of substance

Physical Properties:

Density - ratio of mass to volume

d= m/V

Object: m= 20.4558 g

V=2.13 cm³

d=9.6036619

d=9.60 g/cm³

What is an example of a Density problem?

Rectangular bar measures 0.500 cm in height, 3cm in width and 40 cm in length. It has a mass of 100 grams.

d= m/V

Volume of bar = 60 cm³

Mass of bar= 100g

d= 1.67 g/cm³

What is another Density example?

Mercury density at 20 degrees Celsius is 13.570 g/mL.

What is the mass of 107.3 mL of mercury?

d=m/V

m=d*V

m= (13.570 g/mL) * (107.3 mL)

m= 1456 g

m= 1.456 ×10³ g

What is chemistry?

An experimental science.

What are examples of quantitative measurements?

Length, mass, volume, time, speed and temperature.

What does each measurement have?

2 or 3 parts:

What are the two or three parts each measurement has?

(1) a number

(2) a label or unit

(3) a name

What is an example of a measurement?

6 L of water

6 - Number

L- Label or unit

Water- Name

Why is reporting data in the way of measurements important?

Because if you have a number without a unit, it doesn’t make sense.

Ex: If I said I drove six. Six what? You would not know what I am talking about.

For qualitative observations what does that mean?

. No numbers involved

. Color, appearance, statements like “large” or “small”

. Stating that something is hot or cold without specifying a temperature.

. Identifying something by smell

. No measurements

What do qualitative observations not have?

No measurement or no measured values.

What is SI?

Système International d’ Unites (International System of Units)

What are SI units?

A modified metric system.

What do we have Si base units for?

Length, mass, time and temperature and mole.

What is the SI base unit for mass?

Kilogram (kg)

What is the SI base unit for length?

Meter (m)