WHY DON'T OIL & WATER MIX?

ELEMENTS, COMPOUNDS, & MIXTURES - INTRO

Elements, Compounds, and Mixtures Game from delokarl

SCIENCE NEWS - STUDENT PROJECT

SCIENCE NEWS

Since the start of the school year we have done a wide-range of SCIENCE NEWS to help us learn about the happenings in our world from the incredible people who research, develop, and change our lives with science.

You will research, design, & present a SCIENCE NEWS.

·       Topic:   must have current & detailed research on your science topic of your choice.

·       Format:  must enhance the presentation of facts (video, brochure, graphics, power point, Glogster, hands-on demonstration, audio, ETC…

·       Presentation:  must engage & inform your audience.  Facts delivered must be clear & informative

·       Time:  You will be allowed a maximum of 3 minutes to present your science news. 

·       You must have your topic approved by me before you begin

·       You must sign up for a date for your presentation

MIXTURES - #13

**** ADD THIS FLOW DIAGRAMS IN YOUR NOTES

Separating Mixtures

Many of the substances we use everyday were actually once part of a mixture. Someone somewhere separated that substance from the mixture so we could use it. It turns out that many compounds and elements aren't found in nature in their pure form, but are found as parts of mixtures. Separating substances from mixtures is an important part of chemistry and modern industry. 

Some important chemistry terms are used in this section including mixtures, suspensions, and solutions.  Read carefully.

Chemical Mixtures

One of the main aspects of chemistry is combining different substances. Sometimes combining substances can cause a chemical reaction and bonding which creates an entirely new substance called a compound. However, sometimes there is no chemical reaction or bonding. In this case, a mixture is formed from the combined substances. 

Mixture

A mixture is made when two or more substances are combined, but they are not combined chemically.

General properties of a mixture:

• The components of a mixture can be easily separated
• The components each keep their original properties
• The proportion of the components is variable 

 Types of Mixtures

There are two main categories of mixtures: homogeneous mixtures and heterogeneous mixtures. 

• In a homogenous mixture all the substances are evenly distributed throughout the mixture (salt water, air, blood). 
• In a heterogeneous mixture the substances are not evenly distributed (chocolate chip cookies, pizza, rocks)
  

 

Within the categories of homogeneous and heterogeneous mixtures there are more specific types of mixtures including solutions, alloys, suspensions, and colloids.
Solutions (homogeneous)

A solution is a mixture where one of the substances dissolves in the other. The substance that dissolves is called the solute. The substance that does not dissolve is called the solvent.

• An example of a solution is salt water. These components can be easily separated through evaporation and they each retain their original properties. However, the salt is dissolved into the water to where you can't see it and it is evenly distributed in the water. In this example the water is the solvent and the salt is the solute.

A saturated solution is one containing as much solute as possible without forming a precipitate. This is the maximum concentration of solute.

An unsaturated solution is a chemical solution in which the solute concentration is lower than its equilibrium solubility.

What is the difference between a solution and a mixture?

In chemistry a solution is actually a type of mixture. A solution is a mixture that is the same or uniform throughout. Think of the example of salt water. This is also called a "homogenous mixture." A mixture that is not a solution is not uniform throughout. 

• Think of the example of sand in water. This is also called a "heterogeneous mixture."

Alloys (homogeneous)

An alloy is a mixture of elements that has the characteristic of a metal. At least one of the elements mixed is a metal. 

• One example of an alloy is steel which is made from a mixture of iron and carbon.

Suspensions (heterogeneous)

A suspension is a mixture between a liquid and particles of a solid. In this case the particles do not dissolve. The particles and the liquid are mixed up so that the particles are dispersed throughout the liquid. They are "suspended" in the liquid. A key characteristic of a suspension is that the solid particles will settle and separate over time if left alone.

• An example of a suspension is a mixture of water and sand. When mixed up, the sand will disperse throughout the water. If left alone, the sand will settle to the bottom.

Colloids (heterogeneous)

A colloid is a mixture where very small particles of one substance are evenly distributed throughout another substance. They appear very similar to solutions, but the particles are suspended in the solution rather than fully dissolved. The difference between a colloid and a suspension is that the particles will not settle to the bottom over a period of time, they will stay suspended or float.

• An example of a colloid is milk. Milk is a mixture of liquid butterfat globules dispersed and suspended in water.

Colloids are generally considered heterogeneous mixtures, but have some qualities of homogeneous mixtures as well.

Interesting Facts about Mixtures

• Smoke is a mixture of particles that are suspended in the air.
• Tap water is a mixture of water and other particles. Pure water or H2O is generally referred to as distilled water.
• Many of the substances we come into contact with every day are mixtures including the air we breathe which is a mixture of gases like oxygen and nitrogen.
• Blood is a mixture that can be separated by a machine called a centrifuge into its two main parts: plasma and red blood cells.
• Mixtures can be liquids, gases, and solids.

SEPARATING MIXTURES 

Why do we want to separate mixtures? 

All the way back to Ancient History, industrious humans have separated mixtures in order to obtain the specific substances that they need. One example of this is extracting metal from ore in order to make tools and weapons. We'll discuss some other examples of separation below. 

Separation Processes 

The way in which different substances in a mixture are separated is called a process. There are a number of different processes used for separation. Many of them are very complex and involve dangerous chemicals or high temperatures. A lot of important industries in the world today are based on separation processes. 

Filtration 

One common method of separation is filtration. Filters are used everywhere. We use them in our houses to filter dust and mites out of the air we breathe. We use them to filter impurities from our water. We even have filters in our bodies such as our kidneys which act as filters to get bad stuff out of our blood. 

The filtration process is generally used to separate a suspension mixture where small solid particles are suspended in liquid or air. In the case of filtering water, the water is forced through a paper that is made up of a very fine mesh of fibers. The water that has been run through the filter is called the filtrate. The particles that are removed from the water by the filter are called the residue. 

Distillation 

Another common separation process is called distillation. Distillation uses boiling to separate mixtures of liquid solutions. It takes into account that different substances in the mixture will have different boiling points. 

For example, if you heat salt water the water in the solution will boil before the salt. The water will then evaporate leaving the salt behind. If the steam from the water is collected it will turn back into liquid as it cools. This cooled water will be pure water without any salt. 

Centrifuge In some cases, there are suspension mixtures where the solid particles are too fine to be separated with a filter. In these cases, sometimes a centrifuge is used. Centrifuges are mechanical devices that spin at very high speeds. These high speeds allow the solid particles in suspensions to settle very quickly.  For example, rather than wait for sand to slowly settle to the bottom of water, a centrifuge can cause the sand to settle in a matter of seconds. Some examples of how centrifuges are used include: separating blood into plasma and red cells separating cream from milk separating uranium isotopes for nuclear power plants.

The heavier particles move to the outside of the cylinder as the centrifuge spins allowing the mixture to be separated.

Other Processes 

There are many other separation processes such as sublimation, adsorption, crystallization, and chromatography. Sometimes it takes many stages of processes to get to the final result. 

• One example of this is the processing of crude oil. Crude oil uses many levels of fractional distillation to produce a number of different products including gasoline, jet fuel, propane gas, and heating oil. 

Interesting Facts about Separating Mixtures

• To separate liquid solutions where the substances have similar boiling points, a more complex version of distillation is used called fractional distillation.
• Painting uses the separation process of evaporation. The wet paint is a mixture of color pigment and a solvent. When the solvent dries and evaporates, only the color pigment is left.
• The separation process of winnowing was used in ancient cultures to separate the grain from the chaff. They would throw the mixture into the air and the wind would blow away the lighter chaff, leaving the heavier grain.
• High speed centrifuges can spin up to 30,000 times a minute.
• Many separation processes are occurring constantly in nature.

CHEMISTRY - SALTS #12

Soaps and Salts

What are salts? 

In chemistry, salts are ionic compounds that are formed from the neutralization reactions of an acid and a base. Salts have certain properties:

• Salts are made up of an equal number of anions (positive ions) and cations (negative ions)
• They are hard and brittle
• Most salts dissolve in water and are solids at room temperature
• They have strong bonds and a relatively high boiling point
• Salts are electrically neutral
• In their solid state, they arrange themselves in a rigid structure called a lattice

Salts come in a variety of tastes and colors. Some salts are not safe to eat. 

Table Salt 

What most people call "salt" is the chemical compound sodium chloride. It has the chemical formula NaCl. Sodium chloride dissolves in water and is what makes the ocean water salty. 

Salt is necessary for animal life. It is also used to enhance the taste of our foods and to preserve foods. 

Soap is a Salt 

In chemistry, soap is a type of salt. This is because it is formed from the mixing of an acid and a base. 

How does soap work? 

Soaps and detergents help to clean clothes, skin, dirty dishes, and other items by dissolving grease. Detergents are made up of special molecules. Part of these molecules is attracted to water. The other part is attracted to grease. The part that is attracted to grease will dissolve the grease and break it up into smaller components that can then be rinsed away by water. 

How is soap made? 

Humans have made soap all the way back to the ancient civilizations of the Babylonians and the Egyptians. For many years soap was made from a mixture of ashes, animal fat, and water. Although we no longer make soap the same way, the chemistry for making modern soap is very similar. 

Today soap is often made from a combination of fats and sodium hydroxide. As the soap is formed, the byproduct of glycerol is removed. Once the raw soap is produced, other ingredients like perfumes and colors can be added. The chemical process used to make soaps is called saponification. 

Interesting Facts about Soaps and Salts

• Salts can be made by mixing an acid and a base or an acid and a metal.
• Thallium salt was once used as rat and ant poison.
• The green color of an emerald is because of small amounts of the salt chromium oxide.
• Around 250 million tons of salt was produced in 2010. Most of it is produced by the evaporation of ocean water and salt lakes.
• Glycerol, the byproduct of soap manufacturing, is used for making other chemical compounds such as plastics and explosives.
• Several different salts go into the manufacture of glass.
• Liquid soap was not invented until the late 1800s.
• Soap is a key ingredient in many lubricating greases.

CHEMISTRY - CRYSTALS - #11

Crystals

What are crystals? 

Crystals are a special kind of solid material where the molecules fit together in a repeating pattern. This pattern causes the material to form all sorts of unique shapes. 

Amethyst Crystal

How do they form? 

The process of crystal forming is called crystallization. Crystals often form in nature when liquids cool and start to harden. Certain molecules in the liquid gather together as they attempt to become stable. They do this in a uniform and repeating pattern that forms the crystal. 

In nature, crystals can form when liquid rock, called magma, cools. If it cools slowly, then crystals may form. Many valuable crystals such as diamonds, rubies, and emeralds form this way. 

Another way crystals form is when water evaporates from a mixture. Salt crystals often form as salt water evaporates. 

What unique properties do crystals have? 

Crystals can have very flat surfaces called facets. They can form geometric shapes such as triangles, rectangles, and squares. The shapes are a direct result of the type of molecules and atoms that make up the crystal. Smaller crystals and larger crystals that were formed of the same molecules and in the same method should have similar shapes. 

There are seven basic crystal shapes, also called lattices. They are Cubic, Trigonal, Triclinic, Orthorhombic, Hexagonal, Tetragonal, and Monoclinic. 

Interesting Types of Crystals 

Snowflakes - Snowflakes are ice crystals that are formed high in the clouds when water freezes. They always have six sides or arms, but every one of them is unique. 

Timing crystals - When an electric current is sent through some crystals they vibrate at a very precise frequency. Quartz crystals are used in watches and other electronics to keep an accurate time. 

Quartz - Quartz is a common mineral and crystal. It is one of the hardest common minerals. The gemstone amethyst is a purple type of quartz. 

Diamonds - Diamonds are one of the most valuable minerals on Earth. Not only for jewelry, but diamond is also the hardest substance on earth and is used for special tools such as diamond saws. Diamond is a form of the element carbon. 

Fun facts About Crystals

• Crystallography is the science of studying crystals and how they form.
• Some crystals, like diamonds, are really just one giant molecule made from lots of atoms of a single element.
• A lot of computer screens use liquid crystals for their display.
• They are very popular in jewelry because they can sparkle and come in many different colors.
• Some living organisms are able to produce crystals.

SALT - VIDEO

CHEMISTRY - ACIDS & BASES - #10

Acids and Bases

Acids and Bases are two special kinds of chemicals. Almost all liquids are either acids or bases to some degree. Whether a liquid is an acid or base depends on the type of ions in it.

•  If it has a lot of hydrogen ions, then it is an acid.
•  If it has a lot of hydroxide ions, then it is a base. 

pH Scale 

Scientists use something called a pH scale to measure how acidic or basic a liquid is. 

• pH is a number from 0 to 14. 
• From 0 to 7 are acids, with 0 being the strongest. 
• From 7 to 14 are bases with 14 being the strongest base.
•  If a liquid has a pH of 7, it's neutral. This would be something like distilled water. 

Strong Acids and Bases 

Acids with a low pH of around 1 are very reactive and can be dangerous. The same is true for bases of a pH near 13. Chemists use strong acids and bases to get chemical reactions in the lab. Although they can be dangerous, these strong chemicals can also be helpful to us. 

*** Never handle acids or bases in a chemistry lab unless supervised by your teacher. They can be very dangerous and can burn your skin.

Acids and Bases in Nature 

There are many strong acids and bases in nature. Some of them are dangerous and used as poisons by insects and animals. Some are helpful. Many plants have acids and bases in their leaves, seeds, or even their sap. Citrus fruits like lemons and oranges have citric acid in their juice. This is what makes lemons taste so sour. 

Acids and Bases in our Bodies 

Our bodies use acids and bases too. Our stomachs use hydrochloric acid to help digest foods. This strong acid also kills bacteria and helps to keep us from getting sick. Our muscles produce lactic acid when we exercise. Also, our pancreas uses a base called an alkali to help with digestion. These are just a few examples of how the chemistry of bases and acids help our bodies function. 

Other Uses 

Science and technology makes good use of acids and bases. Car batteries use a strong acid called sulphuric acid. Chemical reactions between the acid and lead plates in the battery help make electricity to start the car. They are also used in many household cleaning products, baking soda, and to make fertilizer for crops. 

Fun Facts

• Acids and bases can help neutralize each other.
• Acids turn litmus paper red, bases turn it blue.
• Strong bases can be slippery and slimy feeling.
• Acids taste sour, bases taste bitter.
• Proteins are made up of amino acids.
• Vitamin C is also an acid called ascorbic acid.
• Ammonia is a base chemical.

ACTIVITIES:
ACID & BASES #1

CHEMISTRY - NAMING COMPOUNDS & BALANCING EQUATIONS #9

Naming Chemical Compounds

Chemical compounds are formed when elements are joined by chemical bonds.    These bonds are so strong that the compound behaves like a single substance. Compounds have their own properties that are unique from the elements they are made of. A compound is a type of molecule with more than one element. 

How Compounds are Named 

Chemists have a specific way of naming compounds. It is a standard method of naming compounds that is used by scientists around the world. The name is built from the elements and the construction of the molecule. 

Basic Naming Convention 

First we'll cover how to name molecules with two elements (binary compounds). The name of a compound with two elements has two words. 

To get the first word we use the name of the first element, or the element to the left of the formula. To get the second word we use the name of the second element and change the suffix to "ide" at the end of the word. 

Some examples of adding the "ide": 

O = oxygen = oxide
Cl = chlorine = chloride
Br = bromine = bromide
F = fluorine = fluoride 

Examples of binary compounds: 

NaCl - sodium chloride
MgS - magnesium sulfide
InP = indium phosphide 

What if there is more than one atom? 

In cases where there is more than one atom (for example there are two oxygen atoms in CO₂) you add a prefix to the start of the element based on the number of atoms. Here is a list of the prefixes used: 

# Atoms 1 2 3 4 5 6 7 8 9 10

Prefix mono- di- tri- tetra- penta- hexa- hepta- octa- nona- deca-

** note: the "mono" prefix is not used on the first element. For example CO = carbon monoxide. 

Examples: 

CO₂ = carbon dioxide
N₂O = dinitrogen monoxide
CCL₄ = carbon tetrachloride
S₃N₂ = trisulfer dinitride 

How is the order of the elements determined? 

When there are two elements in a compound, which element goes first in the name? 

If the compound is made of a metal element and a nonmetal element, then the metal element is first. If there are two nonmetal elements, then the first name is the element to the left side of the periodic table. 

Examples:

• In a compound that contains iron and fluoride, the metal (iron) would go first.
• In a compound that contains carbon and oxygen the element to the left on the periodic table (carbon) would go first.

More Complex Naming Rules 

See below for some of the more complex naming rules. 

Naming Metal-Nonmetal Compounds 

If one of the two compounds is a metal, then the naming convention changes a bit. Using the stock method, a roman numeral is used after the metal to indicate which ion is using the charge. 

Examples: 

Ag₂Cl₂ = silver (II) dichloride
FeF₃ = iron (III) fluoride 

Naming Polyatomic Compounds 

Polyatomic compounds use a different suffix. Most of them end in "-ate" or "-ite". There are a few exceptions that end in "-ide" including hydroxide, peroxide, and cyanide. 

Examples: 

Na₂SO₄ = sodium sulfate
Na₃PO₄ = sodium phosphate
Na₂SO₃ = sodium sulfite 

Naming Acids 

Hydro acids use the prefix "hydro-" and the suffix "-ic". 

HF = hydrofluoric acid
HCl - hydrochloric acid 

Oxoacids containing oxygen use the "-ous" or the "-ic" suffix. The "-ic" suffix is used for the acid that has more oxygen atoms. 

H₂SO₄ = sulfuric acid
HNO₂ = nitrous acid
HNO₃ = nitric acid 

COMPOUND & MIXTURE - REVIEW CLOZE

Use this site to learn about compounds & mixtures.  Read carefully for details.  The cloze is a great review.

COMPLETE the COMPOUNDS & MIXTURE cloze.
DUE:  1/10/2014

REVIEW ACTIVITY:
COMPOUNDS & MIXTURES

Make sure to carefully review all notes & sites for preparation for the Quiz, Tuesday, 1/14
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