CHEMISTRY UNIT - ASSIGNMENTS

1/27-WHY DON'T OIL & WATER MIX - VIDEO

1/13 -ELEMENTS, COMPOUNDS, MIXTURES - pp

1/9- SCIENCE NEWS - STUDENT PROJECT

1/8-MIXTURES  #13

• IMPURE SUBSTANCES - pp

1/7-SALTS  #12

1/7-CRYSTALS  #11

1/6-ACIDS & BASES  #10

• ACIDS & BASES - ACTIVITY

1/6-NAMING COMPOUNDS  #9

• NAMING COMPOUNDS - pp

1/6-COMPOUND & MIXTURE REVIEW - CLOZE  #8

2/5-CHEMICAL REACTIONS - ACIDS/BASES II  #10

• ACID/BASE QUIZ

2/5-CHEMICAL REACTIONS - ACIDS/BASES I   #9

2/4-CHEMICAL REACTIONS - CATALYST  #8

2/4-CHEMICAL REACTIONS - EQUILIBRIUM II  #7

• EQUILIBRIUM - QUIZ

2/4-CHEMICAL REACTIONS - EQUILIBRIUM I  #6

2/4-CHEMICAL REACTIONS - THERMODYNAMICS  #5

• THERMODYNAMICS - QUIZ

2/4- CHEMISTRY QUIZS

• COMPOUNDS & MIXTURES QUIZ

• PHYSICAL & CHEMICAL CHANGES - QUIZ

CHEMICAL REACTIONS - STOICHIOMETRY  #4

2/3-CHEMICAL REACTIONS - MEASURING REACTION RATES  #3

2/3-CHEMICAL REACTIONS - RATE OF REACTION  #2

• CHEMICAL REACTIONS RATE - QUIZ

2/3-ENDOTHERMIC & EXOTHERMIC

• ENDOTHERMIC & EXOTHERMIC - QUIZ

CHEMISTRY QUIZS

COMPOUNDS & MIXTURES QUIZ

PHYSICAL & CHEMICAL CHANGES - QUIZ

ENDOTHERMIC & EXOTHERMIC PROCESS

Endothermic and Exothermic Processes

Exothermic- the word describes a process that releases energy in the form of heat.

Forming a chemical bond  releases energy and therefore is an exothermic process.

Exothermic reactions usually feel hot because it is giving heat to you.

Endothermic - a process or reaction that absorbs energy in the form of heat.

Breaking a chemical bond requires energy and therefore is Endothermic.

Endothermic reactions usually feel cold because it is taking heat away from you.

Exothermic Processes	Endothermic Processes
freezing water solidifying solid salts condensing water vapor making a hydrate from an anhydrous salt forming an anion from an atom in the gas phase Annihilation of matter E=mc2 splitting of an atom	melting ice cubes melting solid salts evaporating liquid water making an anhydrous salt from a hydrate forming a cation from an atom in the gas phase splitting a gas molecule separating ion pairs cooking an egg baking bread

Endothermic and exothermic reactions involve the absorption and release, respectively, of energy to and from the environment.

Exothermic Reaction

An Exothermic Reaction releases energy upon completion.

KEY POINTS

• All chemical reactions involve the transfer of energy.
• Endothermic processes require an input of energy and are signified by a positive change in enthalpy.
• Exothermic processes release energy upon completion, and are signified by a negative change in enthalpy.

TERMS

• endothermic
  of a chemical reaction that absorbs heat energy from its surroundings
• exothermic
  of a chemical reaction that releases energy in the form of heat
• enthalpy
  In thermodynamics, a measure of the heat content of a chemical or physical system.

EXAMPLES

• An example of an exothermic reaction is the mixing of water and strong acids. In the presence of water, the acid will dissociate quickly and release heat.
• An example of an endothermic reaction is the melting of an ice cube. In order to melt the ice cube, heat is required.

1. 

   fig. 2

   Endothermic Reaction

   An endothermic reaction requires energy for completion because the energy of the reactants is less than that of the products.

2. Endothermic and Exothermic Reactions

    An energy diagram can be used to show energy movements in these reactions and temperature can be used to measure them macroscopically.

REVIEW


Many chemical reactions release energy in the form of heat, light, or sound. 
These are exothermic reactions. 

• Exothermic reactions may occur spontaneously and result in higher randomness or entropy (ΔS > 0) of the system. They are denoted by a negative heat flow (heat is lost to the surroundings) and decrease in enthalpy -  the amount of heat content used or released in a system at constant pressure. 
• In the lab, exothermic reactions produce heat or may even be explosive. 

• There are other chemical reactions that must absorb energy in order to proceed. These are endothermic reactions. 
• Endothermic reactions cannot occur spontaneously. Work must be done in order to get these reactions to occur. When endothermic reactions absorb energy, a temperature drop is measured during the reaction. 

Endothermic reactions are characterized by positive heat flow (into the reaction) and an increase in enthalpy (+ΔH). 

Examples of Endothermic and Exothermic Processes

• Photosynthesis is an example of an endothermic chemical reaction. In this process, plants use the energy from the sun to convert carbon dioxide and water into glucose and oxygen. 

•  An example of an exothermic reaction is the mixture of sodium and chlorine to yield table salt. 

ENDOTHERMIC & EXOTHERMIC QUIZ - turn into drawer

WHY DON'T OIL & WATER MIX?

ELEMENTS, COMPOUNDS, & MIXTURES - INTRO

Elements, Compounds, and Mixtures Game from delokarl

ELEMENTS, COMPOUNDS, & MIXTURES - QUIZZES

• There are 2 QUIZZES 
• QUIZ #1 - Click on Highlighted Link (write score on the notebook paper)
• QUIZ #2
• Number a piece of notebook paper 1 - 10, 
• Title - ELEMENT, COMPOUND, MIXTURE - QUIZ.
• You can write just the answers.  Turn into drawer.  
• You can use only notes in your notebook.  
• DUE:  12/16

QUIZ #1 (click highlighted link)

QUIZ #2 - (Notebook paper)

1. An unknown, clear liquid is given to you in a beaker. You transfer the liquid from the beaker to a clean, empty test-tube, and begin to heat it. After a while, you see vapours (which on further analysis you discover are vapours of water) rising from the test-tube, and pretty soon, all that's left are a few crystals of salt stuck to the edges! Was that liquid an element, compound or a mixture? Answer: (element, compound or mixture?)

2. You have just won a block of pure 24-carat gold. Have you just procured an element, compound or mixture? Answer: (element, compound or mixture?)

3. A dish is given to you, which contains a blackish-yellow powder. When you move a magnet over it, you are amazed to see black particles, (which you find out are iron) fly upwards and get stuck to the magnet, and all that's left in the dish is a yellow powder, which you discover to be sulphur (sulfur). Was your original powder an element, compound or mixture? Answer: (element, compound or mixture?)

4. A substance is analysed in a laboratory, and when viewed under an electron microscope, it is revealed that it contains only one kind of atom. Is the substance an element, compound or mixture? Answer: (element, compound or mixture?)

5. *Water* is what all life in the world depends on. Is it an element, compound or mixture? Answer: (element, compound or mixture?)

6. Aqua regia was a liquid used by alchemists to separate silver from gold. Was it an element, compound or mixture? Answer: (element, compound or mixture?)

7. This gas is essential for us, and all other aerobic organisms, to survive. We inhale it along with the air we breathe (of which it forms approximately 21%) and it then helps in the oxidation of glucose in our bodies. When not in its molecular form, is it an element, compound or mixture? Answer: (element, compound or mixture?)

8. A magnesium ribbon is burnt in the air, to form the greyish oxide of magnesium - magnesium oxide (MgO). Is this oxide an element, compound or a mixture? Answer: (element, compound or mixture?)

9. The air we breathe - is it an element, compound or mixture? Answer: (element, compound or mixture?)

10. These are given 'symbols' like 'Ar', 'Zn', 'W' and 'Xe', and are arranged in a table called the Periodic Table. Are they elements, compounds or mixtures?  compounds  elements  mixtures  both elements and compounds

CHEMISTRY - ELEMENT OF THE DAY - SILICON

14

Si

Silicon

28.0855

Atomic Number: 14

Atomic Weight: 28.0855

Phase at Room Temperature: Solid

Element Classification: Semi-metal

Period Number: 3    Group Number: 14    

Group Name: none

What's in a name? From the Latin word for flint, silex.

Say what? Silicon is pronounced as SIL-ee-ken.

History and Uses:

Silicon was discovered by Jöns Jacob Berzelius, a Swedish chemist, in 1824 by heating chips of potassium in a silica container and then carefully washing away the residual by-products. Silicon is the seventh most abundant element in the universe and the second most abundant element in the earth's crust. Today, silicon is produced by heating sand (SiO₂) with carbon to temperatures approaching 2200°C.

Two allotropes of silicon exist at room temperature: amorphous and crystalline. Amorphous appears as a brown powder while crystalline silicon has a metallic luster and a grayish color. Single crystals of crystalline silicon can be grown with a process known as the Czochralski process. These crystals, when doped with elements such as boron, gallium, germanium, phosphorus orarsenic, are used in the manufacture of solid-state electronic devices, such as transistors, solar cells, rectifiers and microchips.

Silicon dioxide (SiO₂), silicon's most common compound, is the most abundant compound in the earth's crust. It commonly takes the form of ordinary sand, but also exists as quartz, rock crystal, amethyst, agate, flint, jasper and opal. Silicon dioxide is extensively used in the manufacture of glass and bricks. Silica gel, a colloidal form of silicon dioxide, easily absorbs moisture and is used as a desiccant.

Silicon forms other useful compounds. Silicon carbide (SiC) is nearly as hard as diamond and is used as an abrasive. Sodium silicate (Na₂SiO₃), also known as water glass, is used in the production of soaps, adhesives and as an egg preservative. Silicon tetrachloride (SiCl₄) is used to create smoke screens. Silicon is also an important ingredient in silicone, a class of material that is used for such things as lubricants, polishing agents, electrical insulators and medical implants.

CHEMISTRY - ELEMENT OF THE DAY - NITROGEN

7

N

Nitrogen

14.0067

Atomic Number: 7

Atomic Weight: 14.0067

Phase at Room Temperature: Gas

Element Classification: Non-metal

Period Number: 2    Group Number: 15    
Group Name: Pnictogen

What's in a name? From the Greek words nitron and genes, which together mean "saltpetre forming."

Say what? Nitrogen is pronounced as NYE-treh-gen.

History and Uses:

Nitrogen was discovered by the Scottish physician Daniel Rutherford in 1772. It is the fifth most abundant element in the universe and makes up about 78% of the earth's atmosphere, which contains an estimated 4,000 trillion tons of the gas. Nitrogen is obtained from liquefied air through a process known as fractional distillation.

The largest use of nitrogen is for the production of ammonia (NH₃). Large amounts of nitrogen are combined with hydrogen to produce ammonia in a method known as the Haber process. Large amounts of ammonia are then used to create fertilizers, explosives and, through a process known as the Ostwald process, nitric acid (HNO₃).

Nitrogen gas is largely inert and is used as a protective shield in the semiconductor industry and during certain types of welding and soldering operations. Oil companies use high pressure nitrogen to help force crude oil to the surface. Liquid nitrogen is an inexpensive cryogenic liquid used for refrigeration, preservation of biological samples and for low temperature scientific experimentation. Jefferson Lab's Frostbite Theater features videos of many basic liquid nitrogen experiments, such as this one:

#video 

CHEMISTRY - ELEMENT OF THE DAY - BORON

5

B

Boron

10.811

Atomic Number: 5

Atomic Weight: 10.811

Phase at Room Temperature: Solid

Element Classification: Semi-metal

Period Number: 2    Group Number: 13    

Group Name: none

What's in a name? From the Arabic word Buraq and the Persian word Burah, which are both words for the material "borax."

Say what? Boron is pronounced as BO-ron.

History and Uses:

Boron was discovered by Joseph-Louis Gay-Lussac and Louis-Jaques Thénard, French chemists, and independently by Sir Humphry Davy, an English chemist, in 1808. They all isolated boron by combining boric acid (H₃BO₃) with potassium. Today, boron is obtained by heating borax (Na₂B₄O₇·10H₂O) with carbon, although other methods are used if high-purity boron is required.

Boron is used in pyrotechnics and flares to produce a green color. Boron has also been used in some rockets as an ignition source. Boron-10, one of the naturally occurring isotopes of boron, is a good absorber of neutrons and is used in the control rods of nuclear reactors, as a radiation shield and as a neutron detector. Boron filaments are used in the aerospace industry because of their high-strength and lightweight.

Boron forms several commercially important compounds. The most important boron compound is sodium borate pentahydrate (Na₂B₄O₇·5H₂O). Large amounts of this compound are used in the manufacture of fiberglass insulation and sodium perborate bleach. The second most important compound is boric acid (H₃BO₃), which is used to manufacture textile fiberglass and is used in cellulose insulation as a flame retardant. Sodium borate decahydrate (Na₂B₄O₇·10H₂O), better known as borax, is the third most important boron compound. Borax is used in laundry products and as a mild antiseptic. Borax is also a key ingredient in a substance known as Oobleck, a strange material 6th grade students experiment with while participating in Jefferson Lab's BEAMS program. Other boron compounds are used to make borosilicate glasses, enamels for covering steel and as a potential medicine for treating arthritis.

CHEMISTRY - ELEMENT OF THE DAY - BERYLLIUM

4

Be

Beryllium

9.012182

Atomic Number: 4

Atomic Weight: 9.012182

Phase at Room Temperature: Solid

Element Classification: Metal

Period Number: 2    Group Number: 2    

Group Name: Alkaline Earth Metal

What's in a name? From the Greek word beryl, a type of mineral.

Say what? Beryllium is pronounced as beh-RIL-ee-em.

History and Uses:

Although emeralds and beryl were known to ancient civilizations, they were first recognized as the same mineral (Be₃Al₂(SiO₃)₆) by Abbé Haüy in 1798. Later that year, Louis-Nicholas Vauquelin, a French chemist, discovered that an unknown element was present in emeralds and beryl. Attempts to isolate the new element finally succeeded in 1828 when two chemists, Friedrich Wölhler of Germany and A. Bussy of France, independently produced beryllium by reducing beryllium chloride (BeCl₂) with potassium in a platinum crucible. Today, beryllium is primarily obtained from the minerals beryl (Be₃Al₂(SiO₃)₆) and bertrandite (4BeO·2SiO₂·H₂O) through a chemical process or through the electrolysis of a mixture of molten beryllium chloride (BeCl₂) and sodium chloride (NaCl).

Beryllium is relatively transparent to X-rays and is used to make windows for X-ray tubes. When exposed to alpha particles, such as those emitted by radium or polonium, beryllium emits neutrons and is used as a neutron source. Beryllium is also used as a moderator in nuclear reactors.

Beryllium is alloyed with copper (2% beryllium, 98% copper) to form a wear resistant material, known as beryllium bronze, used in gyroscopes and other devices where wear resistance is important. Beryllium is alloyed with nickel (2% beryllium, 98% nickel) to make springs, spot-welding electrodes and non-sparking tools. Other beryllium alloys are used in the windshield, brake disks and other structural components of the space shuttle.

Beryllium oxide (BeO), a compound of beryllium, is used in the nuclear industry and in ceramics.

Beryllium was once known as glucinum, which means sweet, since beryllium and many of its compounds have a sugary taste. Unfortunately for the chemists that discovered this particular property, beryllium and many of its compounds are poisonous and should never be tasted or ingested.

CHEMISTRY - ELEMENT OF THE DAY - LITHIUM

3

Li

Lithium

6.941

Atomic Number: 3

Atomic Weight: 6.941

Phase at Room Temperature: Solid

Element Classification: Metal

Period Number: 2    Group Number: 1    

Group Name: Alkali Metal

What's in a name? From the Greek word for stone, lithos.

Say what? Lithium is pronounced as LITH-ee-em.

History and Uses:

Lithium was discovered in the mineral petalite (LiAl(Si₂O₅)₂) by Johann August Arfvedson in 1817. It was first isolated by William Thomas Brande and Sir Humphrey Davy through the electrolysis of lithium oxide (Li₂O). Today, larger amounts of the metal are obtained through the electrolysis of lithium chloride (LiCl). Lithium is not found free in nature and makes up only 0.0007% of the earth's crust.

Many uses have been found for lithium and its compounds. Lithium has the highest specific heat of any solid element and is used in heat transfer applications. It is used to make special glasses and ceramics, including the Mount Palomar telescope's 200 inch mirror. Lithium is the lightest known metal and can be alloyed with aluminium, copper, manganese, and cadmium to make strong, lightweight metals for aircraft. Lithium hydroxide (LiOH) is used to remove carbon dioxide from the atmosphere of spacecraft. Lithium stearate (LiC₁₈H₃₅O₂) is used as a general purpose and high temperature lubricant. Lithium carbonate (Li₂CO₃) is used as a drug to treat manic depression disorder.

CHEMISTRY - ELEMENT OF THE DAY - ARGON

18

Ar

Argon

39.948

Atomic Number: 18

Atomic Weight: 39.948

Phase at Room Temperature: Gas

Element Classification: Non-metal

Period Number: 3    Group Number: 18    

Group Name: Noble Gas

What's in a name? From the Greek word for inactive, argos.

Say what? Argon is pronounced as AR-gon.

History and Uses:

Argon was discovered by Sir William Ramsay, a Scottish chemist, and Lord Rayleigh, an English chemist, in 1894. Argon makes up 0.93% of the earth's atmosphere, making it the third most abundant gas. Argon is obtained from the air as a byproduct of the production of oxygen and nitrogen.

Argon is frequently used when an inert atmosphere is needed. It is used to fill incandescent and fluorescent light bulbs to prevent oxygen from corroding the hot filament. Argon is also used to form inert atmospheres for arc welding, growing semiconductor crystals and processes that require shielding from other atmospheric gases.

Once thought to be completely inert, argon is known to form at least one compound. The synthesis of argon fluorohydride (HArF) was reported by Leonid Khriachtchev, Mika Pettersson, Nino Runeberg, Jan Lundell and Markku Räsänen in August of 2000. Stable only at very low temperatures, argon fluorohydride begins to decompose once it warms above -246°C (-411°F). Because of this limitation, argon fluorohydride has no uses outside of basic scientific research.

CHEMISTRY - END OF MODULE QUZZES

AFTER COMPLETEING THE CHEMISTRY MODULES
Take the QUIZZES until you score 100%.  Turn in results to me.

CHEMISTRY QUIZ

ATOMS QUIZ

CHEMISTRY - ELEMENT OF THE DAY - CHLORINE

17

Cl

Chlorine

35.453

Atomic Number: 17

Atomic Weight: 35.453

Phase at Room Temperature: Gas

Element Classification: Non-metal

Period Number: 3    Group Number: 17    

Group Name: Halogen

What's in a name? From the Greek word for greenish yellow, chloros.

Say what? Chlorine is pronounced as KLOR-een or as KLOR-in.

History and Uses:

Since it combines directly with nearly every element, chlorine is never found free in nature. Chlorine was first produced by Carl Wilhelm Scheele, a Swedish chemist, when he combined the mineral pyrolusite (MnO₂) with hydrochloric acid (HCl) in 1774. Although Scheele thought the gas produced in his experiment contained oxygen, Sir Humphry Davy proved in 1810 that it was actually a distinct element. Today, most chlorine is produced through the electrolysis of aqueous sodium chloride (NaCl).

Chlorine is commonly used as an antiseptic and is used to make drinking water safe and to treat swimming pools. Large amounts of chlorine are used in many industrial processes, such as in the production of paper products, plastics, dyes, textiles, medicines, antiseptics, insecticides, solvents and paints.

Two of the most familiar chlorine compounds are sodium chloride (NaCl) and hydrogen chloride (HCl). Sodium chloride, commonly known as table salt, is used to season food and in some industrial processes. Hydrogen chloride, when mixed with water (H₂O), forms hydrochloric acid, a strong and commercially important acid. Other chlorine compounds include: chloroform (CHCl₃), carbon tetrachloride (CCl₄), potassium chloride (KCl), lithium chloride (LiCl), magnesium chloride (MgCl₂) and chlorine dioxide (ClO₂).

Chlorine is a very dangerous material. Liquid chlorine burns the skin and gaseous chlorine irritates the mucus membranes. Concentrations of the gas as low as 3.5 parts per million can be detected by smell while concentrations of 1000 parts per million can be fatal after a few deep breaths.