SCIENCE
Summary & Practice Sheets
Grade 9 - Integrated
Introduction to Chemistry Analyzing Data
The Structure of the Atom Electrons in Atoms
A Story of Two Substances: Introducing Chemistry
What is Chemistry?
Chemistry is the scientific study of the composition and properties of matter.
Types of Substances
A substance is a kind of matter with uniform composition and properties. It can be classified into natural and synthetic substances.
Natural Substance
Example of Substance : ozone (O3)
Origin : produced in Earth's stratosphere
Uses : shields Earth from the Sun's harmful radiation
Synthetic Substance
Example of Substance : chlorofluorocarbon (CFC)
Origin : produced in laboratory
Uses : used in aerosol sprays, foam food packaging, coolant for air-conditioners and refrigerators
Formation of Ozone
Impact of chlorofluorocarbons (CFCS)
Chemistry helped us to understand the thinning of the ozone layer and linked it to increased levels of stratospheric CFCS.
Chemistry and Matter
Measuring Matter
Scientists study matter and need to compare measurements around the world. Matter refers to any physical substance with mass and that takes up space.
Physical Quantity
Mass
What Is Measured? : amount of matter in an object
SI Unit of Measurement : kilograms (kg)
Dependent on Gravity : no
Weight
What Is Measured? : gravitational force pulling on an object with mass
SI Unit of Measurement : newtons (N)
Dependent on Gravity : yes
Scientists use mass to measure matter as it is not dependent on gravity.
Observing Matter
Scientists use observations to describe matter at three levels.
Level of Observation
Macroscopic Level
Description : objects visible to the naked eye
Example : elbow
Microscopic Level
Description : objects too small to see with the naked eye
Example : muscle tissue
Submicroscopic Level
Description : objects too small to see even with an optical microscope
Example : water molecule
Explaining Observations of Matter Using Scientific Models
A model is a visual representation of something that is too difficult to see or understand.
Type of Model
Physical Model
Description : model that you can see and touch
Visual Model
Description : diagram or illustration that explains an idea
Mathematical Model
Description : model made up of data or equations
Studying Different Types of Matter
Chemistry is considered a central science. Scientists study the composition and properties of many different types of matter. Chemistry is divided into different branches based on the area of study.
Branch of Chemistry / Area of Study
analytical chemistry / composition and structure of matter
biochemistry / structure and chemical reactions of substances in living organisms
environmental chemistry / presence, movement, and impact of chemicals in the environment
industrial chemistry / chemical reactions used in industrial manufacturing processes
inorganic chemistry / properties and behavior of inorganic compounds
organic chemistry / structure, properties, and composition of carbon-containing compounds
physical chemistry / chemical reactions and the physical properties of atoms and molecules
polymer chemistry / composition of large, complex molecules (called polymers)
thermochemistry / heat released or absorbed during chemical reactions
Scientific Methods
Scientific Method
The scientific method is an organized, systematic approach to solving a scientific question.
Observations / Questions
Background research
Hypothesis
Experiment
Analyze result
Conclusion
Does it support the hypothesis?
Communicate findings
Independent Variable
factor that is changed or controlled during the experiment; does not depend on another variable
Dependent Variable
factor that is measured during the experiment depends on the independent variable
Control
sample that stays the same throughout the whole experiment; standard used for comparison
Types of Observations
Different observations are made to gather data during an experiment.
Types of Data
Qualitative Data
Description : data based on observations using your senses
Examples : color, smell, sound
Quantitative Data
Description : data that can be measured and presented numerically
Examples : mass, volume, length
Scientific Theory and Scientific Law
• A scientific theory is a hypothesis based on multiple investigations over time.
• A scientific law is a description of a phenomenon based on multiple investigations over time.
Scientific Research
Types of Scientific Investigations
• Pure research is done to make discoveries and gain new knowledge.
• Applied research is done to solve a specific problem.
Laboratory Safety Symbols and Their Meanings
biological organisms and tissue can be harmful to humans
corrosive chemicals can burn and destroy human tissue
electrical equipment can cause electrical shock or burns
flammable substances can catch fire easily
chemical fumes can harm the eyes and respiratory tract
harmful chemicals can irritate the skin and/or respiratory tract
radioactive materials are very dangerous
sharp objects can cut and slice the skin
toxic chemicals can be poisonous to plants and animals
Laboratory Safety Equipment
Apron or Lab Coat
protects skin and clothing from chemicals and biological materials
Goggles
protects eyes from chemicals, fumes, and sharp objects
Gloves
protects hands from chemicals and biological materials
Protective Gloves
protects hands from extreme heat and cold
Mask
prevents the inhalation of fumes and fungal spores
PRACTICE : Introduction to Chemistry
1. Fill in the missing parts about the scientific method.
2. ______ objects are too small to see with the naked eye.
a. Big
b. Small
c. Microscopic
d. Physical
3. Group the following into natural or synthetic substances.
ozone / water / chlorofluorocarbon / plastic
Synthetic Substances / Natural Substances
4. Explain why scientists use models to describe submicroscopic events.
____________________________________________
5. Identify the meaning of the following safety symbol.
a. Wear protective clothing.
b. Use caution when handling hot objects.
c. Do not wear a necklace.
d. Do not eat in the lab.
6. Match each of the following physical quantities with what is measured.
mass / gravitational force pulling on an object with mass
weight / amount of space occupied by an object
amount of matter in an object
amount of mass per unit volume
7. Select two examples of qualitative observation.
a. color
b. volume
c. mass
d. sound
8. Choose the branch of chemistry that focuses on the composition and structure of matter?
a. industrial chemistry
b. organic chemistry
c. polymer chemistry
d. analytical chemistry
9. Differentiate between a scientific theory and a scientific law.
A scientific theory
_______________________________
A scientific law
_____________________________
10. _______ is the scientific study of the composition and properties of matter.
11. Select the group of elements found in chlorofluorocarbon?
a. chlorine, carbon, nitrogen
b. carbon, chlorine, fluorine
c. hydrogen, oxygen, fluorine
d. chlorine, fluorine, sodium
12. Select where the ozone layer is located in the Earth’s atmosphere.
a. troposphere
b. mesosphere
c. stratosphere
d. thermosphere