الكيمياء: قصة مادتين

Chapter 1: Introduction to Chemistry

• Lesson 1: The Story of Two Substances
• Lesson 2: Chemistry and Matter
• Lesson 3: Scientific Methods
• Lesson 4: Scientific Research

Topic: The Story of Two Substances

• The topic discusses the story of two substances.
• Objectives of the lesson include explaining the concept of chemistry and chemical substances, clarifying how ozone is formed, and stating the importance of the ozone layer.
• Includes describing the development of chlorofluorocarbons.

Importance of Studying Chemistry

• Discovering useful materials in our lives, such as medicine.
• Understanding our lives more fully.
• Increasing faith in God.

Chemistry Defined

• Chemistry is the study of matter and the changes that occur in it.

Chemical Substance Defined

• A chemical substance is anything that occupies space, has mass, and has a specific and constant composition.
• An example of a chemical substance is the ozone layer.

Ozone Layer

• The ozone layer is an example of a chemical substance.
• It is located in the atmospheric layer surrounding the Earth, specifically in the upper stratosphere.
• Ozone is formed when oxygen gas is exposed to ultraviolet radiation and the gas molecules decompose into single atoms.
• These single atoms then react with oxygen gas to form ozone (O3).
• The ozone layer protects living organisms from harmful ultraviolet radiation by absorbing most of it before it reaches Earth.
• The thickness of the ozone layer is measured in Dobson units using instruments on the ground, balloons, satellites, or rockets.
• Note: The ozone hole is not actually a hole, but rather an area where the ozone layer is thinner than the normal level.

Ultraviolet Radiation

• UVB refers to high levels of ultraviolet radiation that can harm living organisms, but organisms can withstand it due to the protection provided by the ozone layer.

Chlorofluorocarbons (CFCs)

• Developed by Thomas Midgley, CFCs are compounds made up of chlorine, fluorine, and carbon.
• CFCs contribute to the reduction of the thickness of the ozone layer.

Uses of CFCs

• CFCs are used in the manufacture of home air conditioners and refrigerators.
• They are used in the production of polymers and as propellants in aerosol cans.
• Chemical substances are defined as anything that occupies space and has a constant and specific composition, such as water and gold.

Formation of Ozone Gas

• Ozone gas forms when oxygen (O2) is exposed to ultraviolet radiation (UV), splitting it into two oxygen atoms (O).
• These oxygen atoms then react with oxygen molecules to form ozone (O3). O2 + UV → O + O and O2 + O → O3.
• It is important because it protects living organisms from harmful UV radiation.

Why Chemists Study Coolants

• Chemists sought coolants that did not depend on ammonia gas because ammonia gas is harmful to living organisms.
• CFCs were considered ideal refrigerants that were safe for the environment because they were non-toxic, non-flammable, and stable.

Models

• An example of a model is a computer model that allows scientists to test designs before manufacturing an aircraft.
• Models can be interpretations of scientific data.

Topic: Chemistry and Matter

• Behavioral objectives dictate that the student should be able to compare mass and weight, explain why chemists are interested in the microscopic description of matter, clarify the concept of models and identify the areas studied by each branch of chemistry.

Properties of Matter

• Matter is the basic component of the universe, like soil and water.
• Some materials occur naturally, such as ozone gas, and some are manufactured, like CFCs.
• Mass is a measure of the amount of matter.
• Weight is a measure of the force of Earth's gravity on matter.

Mass vs Weight

• An object with a mass of 50 grams at sea level will also weigh 50 newtons.
• However, on top of the Himalayas, its weight will be less, although its mass remains constant because weight is affected by Earth's gravity.
• Thus, scientists use the term mass instead of weight because it is a constant value.
• Weight is equal to mass multiplied by the acceleration due to gravity.

Why Chemists Study the Microscopic

• Observations made with the eye regarding the structure reflect the behavior of the material that cannot be seen with the naked eye.
• The chemistry is aimed at explaining events that are not visible to the eye and that result significant changes.
• Models are tools used by scientists and chemists to clarify complex things that are difficult to see or test a conception.

Areas of Study

• Chemistry is a broad field, so chemists specialize in certain areas.
• Mass is constant and is not affected by gravity, while weight varies with gravity.
• For mass, it is consistent and does not change in both cases.
• The weight on the surface of the moon is equal to the weight on the earth's surface.
• Weight decreases during ascent because the acceleration of gravity counteracts the acceleration.
• Weight changes according to the change in gravity, as chemistry is a broad field.

Models Defined

• Models are any tools scientists use to examine, represent, and share data and ideas.

Examples of Models

• A computer model allows scientists to test their designs before manufacturing an aircraft.
• Different models simulate chemical operation which allow chemists to test operations before building factories.
• Model aircraft allow to testing of certain features like resistance to wind.

Relationship of Chemistry and Matter

• Chemistry is the study of the matter and changes that occur in it.
• Understanding chemistry is essential to all types of science, including biology, physics, earth, and environment.
• In science, scientists use mass instead of weight in their measurements because the mass consistent does not affect gravity but different weights with different gravity.
• I would weigh more in Jazan because the force of gravity there is greater.
• Chemists need to describe things microscopically because the structure determines material property.
• Different models can be used for testing designs, chemical operations, and resistance to the wind.
• Scientists use the scientific theories of chemistry to explain things in the world around them.

Chemistry Defined

• Chemistry is the study of matter, and matter is anything that has volume and a definite value of specific gravity.

Chemical Change

• A chemical change occurs when gasses exposed ultraviolet ray 02 splits 0 in turn form 03 because the 03 shields the earth making the uv safe.
• The study of chemistry provides to the creation of things that comfort and provide relief and for creating new medicine that can be used
• Systematic methods in science involve observation which require the compilation is categorized into quantitative: example color, taste, shapes and flavors.

Scientific Methods

• Qualitative information is like color, taste, shape, and smell;
• Quantitative information includes length, height, speed, and temperature.

Hypothesis Requirements

• A hypothesis as a statement that can assessed.
• Hypotheses can be tested and determined to be accurate by scientists world wide.
• Examples of hypothesis of CFCs the Roland- with a the UV interacts resulting that affects the material property.
• An experiment is groups of observation which have is used to evaluate a hypothesis.
• The experiment has comparative values that experiment with other variables to be determined.

Variables

• variables change with is values and quantities.
• A process to resolve situations.
• Science involves use by researcher involving physics chemicals animals biology.

Different Types of Material

• CFCs which is an active ingredient.

The scientific methods in science

• The variables is divided into; A independent variable which change based values in the process.
• A independent variable based is values during the process to change the initial experiment.
• A is Constant variable which is restricted change.

Examples of the variables in experiments

Running experiment:

• Independent value time.
• Dependent value speed.
• Constant areas where experiment performed the variable of participants’
• Reference data of the target at the start line.
• Melted salt

Independent variable:

• Degrees in in temperature, Dependent. – Speed to melt .
• Constant Value the mount water and value of salt.
• Reference data heat and temperature.
• Findings involves the data to make assumptions.
• The data of the hypotheses provides and are truthful. New data is is made a new statement. The assumptions provide factual conclusions.

Types of scientific theory:

• A factual assumption needs to factual information.
• The world requires steps for assessment of new conclusion.

Model Examples

• Molina and Roland.
• CCIF + U → CCIF + CI
• Cl+O →CIO + O
• CIO +O →CIV +O

Laws and Theories

• The explanation based factual the assumption and information.
• An assumption is a summary of information.
• Factual information also creates new assumption to be use to make proper decisions.