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Unit 2 matter & chemical change

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Stuti Christian

on 3 January 2014

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Transcript of Unit 2 matter & chemical change

PBL MATTER AND CHEMICAL CHANGE
- A gas or liquid that boils at or below ordinary temperatures, in a pressurized container. This class includes compressed gases, dissolved gases, and gases liquefied by compression or refrigeration.

-U of W Examples: propane, compressed air, carbon dioxide (fire extinguishers), nitrogen, welding gases

-Handling instructions: Handle with care, do not drop cylinder. Keep cylinder away from potential ignition sources. Store containers in designated areas.

COMPRESSED GAS.
FLAMMABLE AND COMBUSTIBLE MATERIAL
-This class includes solids, liquids, and gases capable of catching fire in the presence of a spark or open flame under normal working conditions.

-U of W Examples: spray paint, gasoline, propane, alcohols, acetone, sodium, toluene, ethanol

-Handling instructions: Keep away from heat sources and other combustible materials. Never smoke around materials. Store in a cool, fire-proof area.

PART A
What are the 8 WHMIS safety symbols, their meaning and precautions you must take with each?

OXIDIZING MATERIAL
-These materials increase the risk of fire if they come in contact with flammable or combustible materials.

-U of W Examples: hydrogen peroxide, oxygen gas, bleach, nitric acid, potassium permanganate

-Handling instructions: Keep away from combustible materials & store in designated area. Keep away from sources of ignition. Never smoke around materials. Wear personal protective equipment (PPE).

POISONOUS AND INFECTIOUS MATERIAL
-These materials can cause death or immediate injury when a person is exposed to small amounts.

-U of W Examples: antifreeze, sodium cyanide, hydrogen sulphide, sulfuric acid, carbon monoxide, acrylonitrile

-Handling instructions: Handle with extreme caution. Wear personal protective equipment, avoid contact with skin and eyes. Avoid inhaling, work in well-vented areas or wear respiratory protection equipment.

CORROSIVE MATERIAL

-This class includes caustic and acid materials that can destroy the skin or eat through metals

-U of W Examples: sodium hydroxide, hydrochloric acid, nitric acid, hydrofluoric acid, sulfuric acid, caustic soda, ammonium hydroxide, cleaners & disinfectants (ie. Tilex)

-Handling instructions: Keep containers tightly closed. Avoid skin & eye contact by wearing personal protective equipment (PPE). Avoid inhaling – use in well-vented area and/or wear PPE.

-These products may self-react dangerously (for example, they may explode) upon standing or when exposed to physical shock or to increased pressure or temperature, or they emit toxic gases when exposed to water.

-U of W Examples: fiberglass repair kits & epoxy resins, nitroglycerine, anhydrous aluminum chloride, picric acid, vinyl chloride

-Handling instructions: Keep away from heat. Open containers carefully, do not drop them. Store material in cool, fire-proof, designated area.

DANGEROUSLY REACTIVE MATERIAL

PART B

Solid,
Liquid,
Gas
3 States of Matter
Solid to liquid = Melting

Liquid to solid = Freezing or
Solidification

Solid to gas = Sublimation

Gas to solid = Deposition

Liquid to gas = Evaporation

Gas to liquid = Condensation

Describe the 6 changes of state.
Physical - Describe the physical characteristics of a substance such as color, luster, density, hardness, crystal shape.

Chemical - Describe how the substance reacts with other substances. An example would be vinegar and baking soda reacting.

Name and describe the two properties of matter.

Classifying Matter
MATTER
PURE SUBSTANCES
Elements
A substance that cannot be broken down further. For example: Gold

These are found on the periodic table of elements.
Compounds
A chemical combination of two or more elements in a fixed proportion.
For example: NaCl (Sodium Chloride)

Compounds have very strong chemical bonds. As the elements combine, they lose their individual characteristics.

Compounds cannot be separated by physical means such as evaporation.

MIXTURE
Mechanical mixtures
You can see more than one part in the mixture
For example: Cookie dough and salad.

These are also called heterogeneous mixtures.

These can be separated by mechanical means such as using hands or filters.


Solution
A mixture where you cannot see the different parts
For example: Vinegar
These are also called homogeneous mixtures.
There is no settling in a solution.
There are no chemical bonds in solutions. When the substances join, they keep their individual characteristics.
Solutions happen because the particles slip between each other so they are evenly distributed.
They can be separated by physical means such as boiling.

Suspension
Suspensions are heterogeneous mixtures that look homogeneous.
Over time, the particles settle out in a suspension.
The particles can be separated by filters or leaving it stand over time.Example: salty water

Collide
These are heterogeneous mixtures in which the particles don’t settle out.
Colloid particles can often be seen in a beam of light.
Example: Milk is a colloid

Observing Changes in Matter
What are the two changes that can occur in matter? Name and describe the two changes.
Physical Change

A physical change is a change in appearance or state of a substance. Composition of the substance always stays the same.
Example: Melting, crystallization
Chemical Change
This occurs when two or more substances react and create new substances.
Example: Vinegar and baking soda reacting to make a carbon dioxide.




What kind of evidence can we look at to help determine if chemical change has happened?

Evidence of chemical change:

Change in color – Dying clothes

Change in odor – Odor given off when striking a match

Forming a solid or gas – Mixing vinegar and baking soda you get carbon dioxide gas


Release or absorption of heat energy – When gasoline burns in an engine it produces heat
What is a problem with trying to determine if physical or chemical change has occurred and what can be done about this?


It is not always easy to tell if physical or chemical change has occurred. Sometimes a chemical analysis needs to be done to determine the type of change.
what is chemical analysis ?
What are some ways that we can control changes in matter to meet human needs?
Use of freeze-drying to make foods easier to prepare and transport

Chemicals from corn can make environmentally friendly pop bottles, remove nail polish and make ethanol fuel for cars
production of plastics
Welding/Melting - manufacture of metal components
PART C
Theories of Matter

8000 BC - Stone Age

Matter consisted of solid materials which could be made into tools

Between 6000 BC and 1000 BC

Early chemists produced valuable metals such as gold and copper
4500 BC - Bronze Age

Heating copper led to the creation of bronze for use in tools

1200 BC – Iron Age

Iron was combined with carbon to make steel for stronger tools


The Hittites in the Middle East first discovered how to extract iron from rocks and melt it into pots and swords



500 - 350 BC

Democratis
Greek philosopher that believed that matter could be broken down into indivisible bits called “atomos”

Aristotle
Another Greek philosopher that believed that everything was made of earth, air, fire and water.

1500 AD

alchemists were the first modern chemists although they weren’t scientists

Alchemists believed it should be possible to change metals into gold

they conducted the first experiments
Modern Chemistry
1600’s - Robert Boyle




Experimented with gases and what happened to them under pressure

Through experiments he became convinced that matter was made of tiny particles

1780’s - Antoine Lavoisier


Known as the “father of modern chemistry,” he developed a system for naming chemicals
1808 - John Dalton
First person to define an element as a pure substance
Came up with the “billiard ball” model of the atom, which was the first theory of atomic structure

1897 – J.J. Thomson


Discovered electrons and came up with the “raisin bun” or “plum pudding” model of the atom: This showed the atom as a positive sphere with electrons (negative charges) embedded in it
1904 – Hantaro Nagaoka
proposed the “solar system” model of the atom: This showed the atom as a positive sphere with electrons orbiting it

1922 – Niels Bohr

Develops the “electron shell” model where electrons move in specific shells or orbits around the nucleus

1930’s – James Chadwick

Discovered the proton (positive charge) and the neutron (no charge) in the nucleus


Today


The quantum mechanics model of the atom is used today: This says that an atom is a cloud of electrons surrounding a nucleus
Part D
8000 BC - Stone Age

Matter consisted of solid materials which could be made into tools

Early Chemists

Between 6000 BC and 1000 BC
Early chemists produced valuable metals such as gold and copper

4500 BC - Bronze Age
Heating copper led to the creation of bronze for use in tools


1200 BC – Iron Age

Iron was combined with carbon to make steel for stronger tools

The Hittites in the Middle East first discovered how to extract iron from rocks and melt it into pots and swords



500 - 350 BC

Democratis
Greek philosopher that believed that matter could be broken down into indivisible bits called “atomos”

Aristotle
Another Greek philosopher that believed that everything was made of earth, air, fire and water.

Modern Chemistry

1600’s - Robert Boyle


Experimented with gases and what happened to them under pressure

Through experiments he became convinced that matter was made of tiny particles

1780’s - Antoine Lavoisier

Known as the “father of modern chemistry,” he developed a system for naming chemicals

1808 - John Dalton

First person to define an element as a pure substance
Came up with the “billiard ball” model of the atom, which was the first theory of atomic structure

1897 – J.J. Thomson

Discovered electrons and came up with the “raisin bun” or “plum pudding” model of the atom: This showed the atom as a positive sphere with electrons (negative charges) embedded in it

Gas particles move around rapidly & take the shape of its container.

Liquid moves fast yet slower than gas and faster than solid & it takes the shape of its container.

Solid particles vibrate and can't take the shape of its container .

1904 – Hantaro Nagaoka
proposed the “solar system” model of the atom: This showed the atom as a positive sphere with electrons orbiting it








1922 – Niels Bohr
Develops the “electron shell” model where electrons move in specific shells or orbits around the nucleus


1930’s – James Chadwick
Discovered the proton (positive charge) and the neutron (no charge) in the nucleus






Today
The quantum mechanics model of the atom is used today: This says that an atom is a cloud of electrons surrounding a nucleus




Plasma
the chemistry of things: what they are made of, how they behave in certain circumstances as well as on their own, and how to identify certain chemicals. The process by which this is done is called chemical analysis.
Electrons, Neutrons, Protons, Atoms and Molecules


Electrons - Negatively charged subatomic particles found in the cloud region of atoms

Protons - Positively charged subatomic particles found in the nucleus

Neutrons - Neutral subatomic particles found in the nucleus

Atoms – The basic building blocks of all matter.

Molecules – A group of at least two atoms held together by chemical bonds. (NaCl = this is a molecule of sodium)



driving question
Explain how the Periodic Table and an understanding of chemistry is important to us in everyday life.

our everyday action use chemical such as
cooking
cleaning
medicine
environmental issues

For cooking we understand the basic concept of how to preserve food or how it rots .
You use chemistry to help decide what cleaner is best for dishes, laundry, yourself, and your home. You use chemistry when you use bleaches and disinfectants and even ordinary soap and water.
You need to understand basic chemistry so you can understand how vitamins, supplements, and drugs can help or harm you.
medicine .
Chemicals come in handy in environmental issues. Some are nutrients & others are pollutants. Cleaning up the environment. Chemicals to handle & grow the environment. Process of handling environment without harming it.
Part E
compounds
what does the chemical formula tell us? show an example of this to help show your answer .



Who came up with the system for organizing elements that we use today? What was this system?

In 1814 Jons Jacob Berzelius created the system still used today. He used letters for the elements instead of symbols






Chemical formulas tell us two things:
- what elements are in the compound
- how many atoms of each element are in the compound, determined by the script number next to each symbol


Periodic Table
Ionic Compounds
Describe what an ion, ionic compound and ionic bond are.

An ion is an atom or group of atoms that has become electrically charged

Ionic compounds are pure substances that form as a result of the attraction of positive and negative ions

Ionic bonds form when positive and negative ions (charges) attract each other
PART F

What two scientists came up with ideas for organizing the elements? Explain what they did.

◦John Newland’s “law of octaves” identified the pattern in which the properties of the elements seemed to repeat at regular intervals, similar to the octave scale in music. Demitri Mendeleev later revised the pattern in 1869. Dmitri Mendeleev then came up with a pattern for the elements based on their properties. He listed the 63 known elements at the time according to their properties and left gaps for elements he was sure would be discovered in the future.







Show what basic information is shown on an element on the Periodic Table.

◦Horizontal rows are called periods (numbered 1-7)
◦Vertical columns form a group, or family of elements (numbered 1-18)
◦Information about the element: Atomic Number, Element Symbol, Element Name, Atomic Mass, and the ion charge
◦They are identified as metals, non-metals, and metalloids




Explain how the Periodic Table is organized in horizontal and vertical rows. What are these rows called and give some information about each row.






Periods or Orbits

•The periodic table is organized into 7 horizontal rows called periods or orbits


• Atomic mass increases when moving left to right across a period


•The properties of elements change as you move across a period but the same pattern of change is repeated in each period.




Groups or Families

•The table is also organized into 18 vertical columns called groups or families alkali metals are the most reactive and alkaline-earth metals is the second most reactive. Noble gases are the most unreactive.

• Example: Alkali metals, alkaline-earth metals, halogens etc

•The elements in a group tend to have similar properties

• Example: Noble gases (group 18) are typically un-reactive


Talk about the different categories of elements: Metals (where they are located on Periodic Table, reactivity and describe), Non-metals (where they are found on the Periodic Table, reactivity, and describe), Noble Gases (reactivity), Metalloids (brief description and where they are found)





◦Metals are on the left side of the staircase…they are shiny, malleable, ductile and conduct electricity.
◦Alkali metals are the most reactive metals.







◦Non-metals are on the right side of the staircase…they are dull, brittle and nonconductive. They can be a solid or gas.



◦Halogens (group 17) are the most reactive non-metals.

◦Noble gases are in group 18 and are the most stable and un-reactive elements.

◦Metalloids are directly above and below the staircase…they show properties of both metals and non-metals.
What is the difference between Atomic number and Atomic mass? Explain.

Atomic number is the number of protons (p+) in an element. Atoms are neutral (not charged) which means the number of protons is equal to the number of electrons (e−)
Atomic mass = mass of protons (p+) + mass of neutrons (n0)

What is the Mass number and explain how you figure it out?

Mass number = # of p+ + # of n0
To figure out the mass number of an element, round the atomic mass (on periodic table) to the nearest whole number
Example - Sodium (Na) has an atomic mass of 22.99 g/mol, so its mass number is 23

Explain how to calculate the number of neutrons in an element.
To calculate the number of neutrons (n0) in an element: # n0 = mass number – atomic number (#p+)
Example: Ne (Neon)
Atomic Number = 10
Atomic Mass = 20.18
Mass Number = 20
Neutrons = 20-10 = 10


How do you find out how many electrons are in an element?

For a neutral element the number of electrons is equal to the atomic number.


What is the definition of a chemical reaction?




A chemical reaction occurs when a substance or substances react to produce a new substance


What does a chemical equation do? Show this with an example.

A chemical equation is used to show the chemical reaction.
Example- reactants products

A + B C + D

reaction direction

the two parts of a chemical equation and explain?

The two parts of a chemical reaction are reactants and products:
- Reactants are the substance (s) that you start with are used up
- Products are the substance (s) that you make or produce

What are two ways we can write a chemical equation? Show with an example.

You can write a chemical formula in two ways:
1. as a word equation - Hydrogen + Oxygen Water Vapour
2. using chemical formulas and states of matter - H2 (g) + O2 (g) H2O (g)

What are the two types of chemical reactions and explain please?

The two types of chemical reactions are exothermic and endothermic:
Exothermic Chemical Reaction - a chemical reaction that releases energy is called exothermic. Energy released can be heat, light, sound and electricity. Examples: burning wood
Endothermic Reaction - a chemical reaction that absorbs or requires energy called endothermic. Many require heat but could also require electricity or UV radiation. Examples:
Cooking food or recharging a battery




Name and describe the three types of reactions with oxygen.

The three types of reactions with oxygen are combustion, corrosion, and cellular respiration:
◦ 1. Combustion - occurs when oxygen reacts with a substance to produce a new substance and energy. Example: lighting fire
◦ 2. Corrosion - occurs when oxygen in the atmosphere gradually reacts with a metal producing rust
◦ 3. Cellular Respiration - occurs only in cells and is the reaction of organic material (food) with oxygen




What is the Law of Conservation of Mass?

◦The law of conservation of mass:
- states that the total mass of the reactants is equal to the total mass of the products in every chemical reaction
- when a chemical reaction takes place, matter is not created or destroyed, it is only rearranged



What are four factors that affect the rate of reaction in a chemical reaction? Name and explain each. (This is grade 8 stuff)


◦Reaction Rate is the speed at which a chemical reaction takes place


◦The four factors that affect the rate of a reaction are:
1. Presence of a Catalyst
substances that help a reaction proceed faster without being used up themselves.
can be found in non-living and livings systems
example of catalyst I'd enzymes which is found in our body

2. Concentration of the Reactants:
a higher concentration of reactants means there are more particles around
to bump into each other and react

3. Temperature of the System:
higher temperature speeds up the motion of the particles which makes them
bump into each other and react

4. Surface area of the Reactants:
a higher surface area of the reactants means more particles are exposed and able to react with other reactant particles




What are some characteristics of ionic compounds?


They:
are solids at room temperature
have defined crystal structure
conduct electricity when liquid or dissolved in water have high melting points


What are the two types of systems where chemical reactions can occur and explain?


◦The two types of systems are closed and open systems:
Closed - is a system where matter cannot escape. Example: heated nitrogen and hydrogen in a closed container N2 + 3H2 <---> 2NH3
Open - is a system where matter can escape. Example: adding 10g of alka-seltzer to 100g of water in a beaker causes carbon dioxide to be given off. When the reaction is complete, mass of the products left in the beaker is only 106g, not 110g. This doesn't mean that mass was not conserved. The carbon dioxide gas was also one of the products of the reaction, but it escaped from the open beaker into the air.



Explain why atoms would lose or gain electrons and describe what metals do and non-metals do. Also show where the charge is on the Periodic Table.


•Ions are formed when atoms either lose or gain electrons. Atoms lose or gain electrons to become more stable. Noble gases are the most stable elements.

Metals:
lose electrons and form positive ions called cations
are named by their metal name, followed by the word “ion”
examples are sodium ion and lithium ion

Non-metals:
gain electrons and form negative ions called anions
are named by changing the ending of the non-metal to “ide”, then followed by the word “ion”
examples are oxide ion and chloride ion



How does a molecular compound form and what is this called?

•A molecular compound forms when two or more non-metals join together. They are joined by the sharing of electrons which is called a covalent bond.




What are some characteristics of molecular compounds?


•Can be solids, liquids, or gases at room temperature
•Do NOT conduct electricity when liquid or dissolved in water
•Have low melting points






Risks: MATERIALS WHICH HAVE HARMFUL EFFECTS AFTER REPEATED EXPOSURES OR OVER LONG PERIODS OF TIME
• May cause death or permanent injury
• May cause birth defects or sterility
• May cause cancer
• May be sensitizer causing allergies

Precautions: WEAR APPROPRIATE PERSONAL PROTECTION WORK IN A WELL VENTILATED AREA
• Store in appropriate designated areas
• Avoid direct contact
• Use hand, body, face and eye protection
• Ensure respiratory and body protection is appropriate for the specific hazard




Risks: INFECTIOUS AGENTS OR A BIOLOGICAL TOXIN CAUSING A SERIOUS DISEASE OR DEATH
• May cause anaphylactic shock
• Includes Viruses, Yeasts, Moulds, Bacteria and Parasites which affect humans
• Includes fluids containing toxic products
• Includes cellular components

Precautions: SPECIAL TRAINING REQUIRED WORK IN DESIGNATED BIOLOGICAL AREAS WITH APPROPRIATE ENGINEERING CONTROLS
• Avoid forming aerosols
• Avoid breathing vapours
• Avoid contamination of people / area
• Store only in special designated areas




TOXIC
Biohazardous Infectious
an ionized gas consisting of positive ions and free electrons in proportions resulting in more or less no overall electric charge, typically at low pressures (as in the upper atmosphere and in fluorescent lamps) or at very high temperatures (as in stars and nuclear fusion reactors).


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