HAPPY NEW YEAR 2014

The spirit of the horse is recognized to be the Chinese people's ethos – making unremitting efforts to improve themselves. It is energetic, bright, warm-hearted, intelligent and able. Ancient people liked to designate an able person as 'Qianli Ma', a horse that covers a thousand li a day (one li equals 500 meters).

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

P.S. - GASES #8

Looking for a Gas

Gas is everywhere. There is something called the atmosphere. That's a big layer of gas that surrounds the Earth. Gases are random groups of atoms. In solids, atoms and molecules are compact and close together. Liquids have atoms that are spread out a little more. Gases are really spread out and the atoms and molecules are full of energy. They are bouncing around constantly. 

Gases can fill a container of any size or shape. It doesn't even matter how big the container is. The molecules still spread out to fill the whole space equally. That is one of their physical characteristics. Think about a balloon. No matter what shape you make the balloon, it will be evenly filled with the gas molecules. The molecules are spread equally throughout the entire balloon. Liquids can only fill the bottom of the container, while gases can fill it entirely. The shape of liquids is really dependent on the force of gravity, while gases are light enough to have a little more freedom to move. 

You might hear the term "vapor." Vapor and gas mean the same thing. The word vapor is used to describe gases that are usually found as liquids. Good examples are water (H₂O) or mercury (Hg). Compounds like carbon dioxide (CO₂) are usually gases at room temperature, so scientists will rarely talk about carbon dioxide vapor. Water and mercury are liquids at room temperature, so they get the vapor title when they are in a gaseous phase. 

Compressing Gases

Gases hold huge amounts of energy, and their molecules are spread out as much as possible. With very little pressure, when compared to liquids and solids, those molecules can be compressed. It happens all of the time. Combinations of pressure and decreasing temperature force gases into tubes that we use every day. You might see compressed air in a spray bottle or feel the carbon dioxide rush out of a can of soda. Those are both examples of gas forced into a smaller space than it would want, and the gas escapes the first chance it gets. The gas molecules move from an area of high pressure to one of low pressure. 

P.S. - ENERGY TRANSFER #7

Evaporation of Liquids

Sometimes a liquid can be sitting in one place (maybe a puddle) and its molecules will become a gas. That's the process called evaporation. It can happen when liquids are cold or when they are warm. It happens more often with warmer liquids. You probably remember that when matter has a higher temperature, the molecules have a higher energy. When the energy in specific molecules reaches a certain level, they can have a phase change. Evaporation is all about the energy in individual molecules, not about the average energy of a system. The average energy can be low and the evaporation still continues. 

You might be wondering how that can happen when the temperature is low. It turns out that all liquids can evaporate at room temperature and normal air pressure. Evaporation happens when atoms or molecules escape from the liquid and turn into a vapor. Not all of the molecules in a liquid have the same energy. When you have a puddle of water (H₂O) on a windy day, the wind can cause an increased rate of evaporation even when it is cold out. 

Energy Transfer

The energy you can measure with a thermometer is really the average energy of all the molecules in the system. There are always a few molecules with a lot of energy and some with barely any energy at all. There is a variety, because the molecules in a liquid can move around. The molecules can bump into each other, and when they hit... Blam! A little bit of energy moves from one molecule to another. Since that energy is transferred, one molecule will have a little bit more and the other will have a little bit less. With trillions of molecules bouncing around, sometimes individual molecules gain enough energy to break free. They build up enough power to become a gas once they reach a specific energy level. In a word, when the molecule leaves, it has evaporated. 

The rate of evaporation can also increase with a decrease in the gas pressure around a liquid. Molecules like to move from areas of higher pressure to lower pressure. The molecules are basically sucked into the surrounding area to even out the pressure. Once the vapor pressure of the system reaches a specific level, the rate of evaporation will slow down. 

P.S. - LIQUID BASICS #6

Liquid Basics

The second state of matter we will discuss is a liquid. Solids are things you can hold that maintain their shape. Gases are floating around you or trapped in bubbles. What is a liquid? Water is a liquid. Your blood is a liquid. Liquids are an in-between state of matter. They can be found between the solid and gas states. They don't have to be made up of the same molecules. If you have a variety of materials dissolved in a liquid, it is called a solution. 

One characteristic of a liquid is that it will fill up the shape of a container. If you pour some water (H₂O) in a cup, it will fill up the bottom of the cup first and then fill the rest. The water will also take the shape of the cup. The top part of a liquid will usually have a flat surface. That flat surface is the result of gravity pulling on the molecules. Putting an ice cube (solid) into a cup will leave you with a cube in the middle of the cup because it is a solid. The shape of the solid cube won't change until the ice becomes a liquid. 

Another trait of a liquid is that it is difficult to compress. When you compress something, you measure out a certain amount of material and force it into a smaller space. Solids are very difficult to compress and gases are very easy. Liquids are in the middle, but tend to be difficult. When you compress something, you force the atoms closer together. When the pressure goes up, substances are compressed. Liquids already have their atoms close together, so they are hard to compress. Many shock absorbers in cars compress liquids in sealed tubes. 

Molecules Sticking Together

A special force keeps liquids together. Those intermolecular forces make sure that the molecules of the liquid stick to each other. Solids are stuck together and you have to force them apart. Gases bounce everywhere and they try to spread themselves out. Liquids actually want to stick together. There will always be the occasional evaporation, where extra energy gets a molecule excited and the molecule leaves the system. Overall, liquids have cohesive (sticky) forces at work to hold the molecules together. 

PHASES OF MATTER

PHASES OF MATTER GAME

PHASES OF MATTER #2

PHASES OF MATTER #3

Recall: Temperature is a measure of the average kinetic energy (energy of motion) of all the molecules or atoms in a material. All atoms are in motion to a lesser or greater extent, whether that be atomic vibrations in a rigid solid, or straight line motions in a gas.

In the gaseous state, molecules have so much kinetic energy that they fly off in all directions but repeatedly collide and bounce off of other molecules.
--- boiling temperature - condensation temperature ---
In the liquid state, atoms or molecules have sufficient kinetic energy to overcome the chemical bonds that held them in their crystal lattice and move independently, yet they don't have enough energy to separate completely from other atoms.
--- melting temperature - crystallization temperature ---
In the solid state, chemical bonds are stronger than the kinetic energy of the atoms. The atoms are locked into their crystal lattice positions. ***************************************** REVIEW We learned in some of our other lessons that matter is made up of atoms and molecules. Millions and millions of these tiny objects fit together to form larger things like animals and planets and cars. Matter includes the water we drink, the air we breathe, and the chair we are sitting on.  States or Phases  Matter usually exists in one of three states or phases: solid, liquid, or gas. The chair you are sitting on is a solid, the water you drink is liquid, and the air you breathe is a gas.  Changing State  The atoms and molecules don't change, but the way they move about does. Water, for example, is always made up of two hydrogen atoms and one oxygen atom. However, it can take the state of liquid, solid (ice), and gas (steam). Matter changes state when more energy gets added to it. Energy is often added in the form of heat or pressure.  Water  Solid water is called ice. This is water with the lowest energy and temperature. When solid, the molecules in water are held tightly together and don't move easily.  Liquid water is just called water. As ice heats up it will change phases to liquid water. Liquid molecules are looser and can move about easily.  Gas water is called steam or vapor. When water boils it will turn to vapor. These molecules are hotter, looser, and moving faster than the liquid molecules. They are more spread apart and can be compressed or squished. The three states of Water More States  There are actually two more states or phases that matter can take, but we don't see them much in our everyday life.  One is called plasma. Plasma occurs at very high temperatures and can be found in stars and lightning bolts. Plasma is like gas, but the molecules have lost some electrons and become ions.  Another state has the fancy name Bose-Einstein condensates. This state can occur at super low temperatures.  Fun Facts about Solids, Liquids, Gases Gases are often invisible and assume the shape and volume of their container. The air we breathe is made up of different gases, but it is mostly nitrogen and oxygen. We can see through some solids like glass. When liquid gasoline is burned in a car, it turns into various gases which go into the air from the exhaust pipe. Fire is a mixture of hot gases. Plasma is by far the most abundant state of matter in the universe because stars are mostly plasma. STATES OF MATTER

P.S. - SOLID BASICS #5

Solid Basics

So, what is a solid? Solids are usually hard, because their molecules have been packed together. You might ask, "Is baby power a solid? It's soft and powdery." Baby power is also a solid. It's just a ground down piece of talc. Solids can be hard, soft, big or small like grains of sand. The key is that the solids hold their shape and they don't flow like a liquid. A rock will always look like a rock unless something happens to it. The same goes for a diamond. Even when you grind up a solid into a powder, you will see tiny pieces of that solid under a microscope. Liquids will flow and fill up any shape of container. Solids like their shape. 

In the same way that a solid holds its shape, the atoms inside of a solid are not allowed to move around too much. This is one of thephysical characteristics of solids. Atoms and molecules in liquids and gases are bouncing and floating around, free to move where they want. The molecules in a solid are stuck in a specific structure or arrangement of atoms. The atoms still spin and theelectrons fly around, but the entire atom will not change position. Solids can be made up of many things. They can have pure elements or a variety of compounds inside. When you get more than one type of compound in a solid it is called a mixture. Most rocks are mixtures of many different compounds. Concrete is a good example of a man-made mixture. 

Granite is a mixture you might find when you are hiking around a park. Granite is made up of little pieces of quartz, mica, and other particles. Because all of the little pieces are spread through the rock in an uneven way, scientists call it a heterogeneous mixture. This is important because there are different concentrations of specific particles in different parts of the rock. In one place there might be a lot of quartz and very little feldspar, but only a few inches away those amounts might flip. 

Crystals

On the other end of the spectrum from a mixture is something called a crystal. When a solid is made up of a pure substance and forms slowly, it can become a crystal. Not all pure substances form crystals, because it is a very delicate process. The atoms are arranged in a regular repeating pattern called acrystal lattice. A crystal lattice is a very exact organization of atoms. A good example is carbon (C). A diamond is a perfect crystal lattice of carbon, while the graphite arrangement of carbon atoms is a more random and disorganized. You can find graphite in your pencils. For carbon, those two different structures (crystal lattice vs. random arrangement) are called allotropes. 

P.S. - CHEMICAL VS. PHYSICAL CHANGES #4

Chemical vs. Physical Changes

It is important to understand the difference between chemical and physical changes. The two types are based on studying chemical reactions and states of matter. We admit that some changes are obvious, but there are some basic ideas you should know. Physical changes are about energy and states of matter. Chemical changes happen on a molecular level when you have two or more molecules that interact and create a new molecule or two. 

When you step on a can and crush it, you have forced a physical change. The shape of the object has changed. It wasn't a change in the state of matter, because the energy in the can did not change. When you melt an ice cube (H₂O), you have also forced a physical phase change by adding energy. That example caused a change in the state of matter. You can cause physical changes with forces like motion, temperature, and pressure. 

Looking at Molecules

Chemical changes happen on a much smaller scale. While some experiments show obvious chemical changes, such as a color change, most chemical changes that happen between molecules are not seen. When iron (Fe) rusts, you can see it happen over a long period of time. The actual molecules have changed their structure (the iron oxidized). Melting a sugar cube is a physical change, because the substance is still sugar. Burning a sugar cube is a chemical change. Fire activates a chemical reaction between sugar and reactions (O₂). The oxygen in the air reacts with the sugar, and the chemical bonds are broken. 

Some chemical changes are extremely small. They happen over a series of steps. The result might have the same number of atoms, but it will have a different structure or combination of atoms. The sugars glucose, galactose, and fructose all have six carbon atoms, twelve hydrogen atoms, and six oxygen atoms (C₆H₁₂O₆). Even though they are made of the same atoms, they have very different shapes and are called structural isomers. Those isomers have atoms bonded in different orders. Also, each of the sugars goes through different chemical reactions because of the differences in their molecular structure. Scientists say that the arrangement of atoms allows for a high degree of specificity, especially in the molecules you find in living 
things.
 


A physical property is an aspect of matter that can be observed or measured without changing it. 

• Examples of physical properties include color, molecular weight and volume.

A chemical property may only be observed by changing the chemical identity of a substance. This property measures the potential for undergoing a chemical change. 

• Examples of chemical properties include reactivity, flammability and oxidation states.

Physical changes involve states of matter and energy. 

• No new substance is created during a physical change, although the matter takes a different form. 
• The size, shape, and color of matter may change. 
• Also, physical changes occur when substances are mixed, but don't chemically react. One way to identify a physical change is that such a changes may be reversible, especially phase changes. For example, if you freeze an ice cube, you can melt it into water again. 

This is a list of 10 examples of physical changes.

1. crushing a can
2. melting an ice cube
3. boiling water
4. mixing sand and water
5. breaking a glass
6. dissolving sugar and water
7. shredding paper
8. chopping wood
9. mixing red and green marbles
10. sublimating dry ice 

Chemical changes involve chemical reactions and the creation of new products. Typically, a chemical change is irreversible. 

This is a list of 10 examples of chemical changes.

1. rusting of iron
   
2. combustion (burning) of wood
   
3. metabolism of food in the body
   
4. mixing an acid and a base, such as hydrochloric acid (HCl) and sodium hydroxide (NaOH)
   
5. cooking an egg
   
6. digesting sugar with the amylase in saliva
   
7. mixing baking soda and vinegar to produce carbon dioxide gas
   
8. baking a cake
   
9. electroplating a metal
   
10. using a chemical battery

CLASSIFY MATTER

P.S. - CHANGING STATES OF MATTER #3

Changing States of Matter

All matter can move from one state to another. It may require extreme temperatures or extreme pressures, but it can be done. Sometimes a substance doesn't want to change states. You have to use all of your tricks when that happens. To create a solid, you might have to decrease the temperature by a huge amount and then add pressure. Some of you know about liquid nitrogen (N₂). It is nitrogen from the atmosphere in a liquid form and it has to be super cold to stay a liquid. What if you wanted to turn it into a solid but couldn't make it cold enough? You could increase the pressure to push those molecules together. The opposite works too. If you have a liquid at room temperature and you wanted a gas you could use a combination of high temperatures and low pressures to solve your problem. 

Phase changes happen when certain points are reached. Sometimes a liquid wants to become a solid. Scientists use something called a freezing point to measure the temperature at which a liquid turns into a solid. There are physical effects that can change the freezing point. Pressure is one of those effects. When the pressure surrounding a substance goes up, the freezing point and other special points also go up. That means it's easier to keep things solid at higher pressures. Just remember that there are some exceptions. Water (H₂O) is special on many levels. It has more space between its molecules when it is frozen. There's a whole expanding effect when the molecules organize into a solid state. Generally, when temperatures get colder, solids shrink in size. They become more dense. 

CHEMISTRY TERM	PHASE CHANGE
Fusion (melting) Freezing Vaporization (boiling) Condensation Sublimation Deposition	Solid to Liquid Liquid to Solid Liquid to Gas Gas to Liquid Solid to Gas Gas to Solid

Solid to Liquid and Back to Solid

Imagine that you are a solid. You're a cube of ice sitting on a counter. You dream of becoming liquid water. You need some energy. The atoms in a liquid have more energy than the atoms in a solid. The easiest energy to find is probably heat. There is a special temperature for every substance called the melting point. When a solid reaches the temperature of its melting point, it can become a liquid. For water, the temperature has to be a little over zero degrees Celsius (0^oC). If you were salt, sugar, or wood, your melting point would be higher than that of water. How do you know that? If their melting points were lower, they would be liquids at room temperature. The reverse of the melting process is called freezing. Liquid water freezes and becomes solid ice when the molecules lose a lot of energy. 

Solid to Gas and Back to Solid

You are used to solids melting and becoming liquids. Some of you may have also seen a solid become a gas. It's a process called sublimation. The easiest example of sublimation might be dry ice. Dry ice is solid carbon dioxide (CO₂). Amazingly, when you leave dry ice out, it just turns into a gas. Have you ever heard of liquid carbon dioxide? It can be made, but not in normal situations. Can you go from a gas to a solid? Sure. It's called deposition when a gas becomes a solid without going through the liquid state of matter. Those of you who live near the equator may not have seen it, but closer to the poles we see frost on winter mornings. Those little frost crystals on plants build up when water vapor becomes a solid. 

Liquid to Gas and Back to Liquid

When you are a liquid and want to become a gas, you need to find a lot of energy. Once you can start to pump that energy into your molecules, they will start to vibrate. If they vibrate enough, they can escape the limitations of the liquid environment and become a gas. When you reach your boiling point, the molecules in your system have enough energy to become a gas. 

The reverse is true if you are a gas. You need to lose some energy from your very excited gas atoms. The easy answer is to lower the surrounding temperature. When the temperature drops, energy will be transferred out of your gas atoms into the colder environment. When you reach the temperature of the condensation point, you become a liquid. If you were steam over a boiling pot of water and you hit a wall, the wall would be so cool that you would quickly become a liquid. The wall absorbed some of your extra energy. 

Gas to Plasma and Back to Gas

Let's finish up by imagining you're a gas like neon (Ne). You say, "Hmmmm. I'd like to become a plasma. They are too cool!" As a gas, you're already halfway there, but you still need to tear off a bunch of electrons from your atoms. Electrons have a negative charge. Eventually, you'll have groups of positively and negatively charged particles in almost equal concentrations. They wind up in a big plasma ball. When the ions are in equal amounts, the charge of the entire plasma is close to neutral.Neutral happens when a whole bunch of positive particles cancel out the charges of an equal bunch of negatively charged particles. 

Plasma can be made from a gas if a lot of energy is pushed into the gas. In the case of neon, it is electrical energy that pulls the electrons off. When it comes time to become a gas again, just flip the neon light switch off. Without the electricity to energize the atoms, the neon plasma returns to its gaseous state. We have a special world here on Earth. We have an environment where you don't find a lot of everyday plasma. Once you leave the planet and travel through the Universe, you will find plasma everywhere. It's in stars and all of the space in between. 

MELTING & BOILING POINTS - ACTIVITY

P.S. - STATES OF MATTER #2

States of Matter

There are five main states of matter. Solids, liquids, gases, plasmas, and Bose-Einstein condensates (BEC) are all different states of matter. Each of these states is also known as a phase. Elements and compounds can move from one phase to another when specific physical conditions are present. One example is temperature. When the temperature of a system goes up, the matter in the system becomes more excited and active. Scientists say that it moves to a higher energy state. Generally, as the temperature rises, matter moves to a more active state. 

Think about it this way. Remember that glass of water (H₂O) we talked about? When the temperature of the water goes up, the molecules get more excited and bounce a lot more. If you give a liquid water molecule enough energy, it escapes the liquid phase and becomes a gas. Have you ever noticed that you can smell a turkey dinner after it starts to heat up? As the energy of the molecules inside the turkey heat up, they escape as a gas. You are able to smell those volatile gas molecules. 

A "phase" describes a physical state of matter. The key word to notice is physical. Things only move from one phase to another by physical means. If energy is added (like increasing the temperature) or if energy is taken away (like freezing something), you have created a physical change. 

A compound or element can move from one phase to another, but still be the same substance. You can see water vapor, in the form of steam, over a boiling pot of water. That vapor (or gas) can condense and become a drop of water. If you put that drop in the freezer, it would become a solid piece of ice. No matter what phase it was in, it was always water. It always had the same chemical properties. On the other hand, a chemical change would change the way the water acted, eventually making it not water, but something completely different. If you added a carbon (C) atom to a water molecule, you would have formaldehyde (H₂CO), and that is nothing like water. 

STATES OF MATTER

COMPOUNDS, MIXTURES, & MORE VIDEOS & ACTIVITIES

SOLIDS, LIQUIDS, & GASES

SOLIDS, LIQUIDS, & GASES - ACTIVITY

ELEMENTS & COMPOUNDS

PHYSICAL & CHEMICAL CHANGES

MELTING POINTS

MIXTURES



COMPOUNDS & MIXTURES - ACTIVITY

P.S. - INTRO - MATTER #1

Matter is the Stuff Around You

Matter is everything around you. Matter is anything made of atoms and molecules. Matter is anything that has mass and takes up space. If you are new to the idea of mass, it is the amount of stuff in an object. We talk about the difference between mass and weight in another section. Matter is sometimes related to light and electromagnetic radiation. Even though matter can be found all over the Universe, you only find it in a few forms. As of 1995, scientists have identified five physical states of matter. Each of those states is sometimes called a phase. They may even discover one more state by the time you get old. 

Five States of Matter

You should know about solids, liquids, gases, plasmas, and one state called the Bose-Einstein condensate (BEC). Scientists have always known about solids, liquids, and gases. Plasma was a new idea when it was noticed by William Crookes in 1879. The scientists who worked with the Bose-Einstein condensate received a Nobel Prize for their work in 1995. But what makes a state of matter? It's about the physical state of the molecules and atoms. Think about solids. They are often hard and brittle. Liquids are all fluidy at room temperature. Gases are there, but you usually smell them before you can see them. You don't see them because their molecules are really far apart. The BEC is all about molecules that are really close to each other (even closer than atoms in a solid). 

Changing States of Matter

Elements and compounds can move from onephysical state to another and not change their basic atomic parts. Oxygen (O₂) as a gas still has the same properties as liquid oxygen. The liquid state is colder and denser, but the molecules (the basic parts) are still the same. Water (H₂O) is another example. A water molecule is made up of two hydrogen (H) atoms and one oxygen (O) atom. It has the same molecular structure whether it is a gas, liquid, or solid. Although its physical state may change, its chemical state remains the same. 

So you're asking, "What is a chemical change?" Let's start with a glass of pure water. If the formula of water were to change, that would be a chemical change. If you could just add a second oxygen atom, you would have hydrogen peroxide (H₂O₂). The molecules in your glass would not be water anymore. A chemical change happens when the atoms in a molecule are moved around or when atoms are added or taken away. Chemical changes happen when bonds between atoms are created or destroyed. Changing physical states of matter is about changing densities, pressures, temperatures, and other physical properties. The basic chemical structure does not change when there is a physical change.