Physical+Science

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= Big Idea: Matter is described by its properties and many undergo changes. = toc

Essential Question: What properties define matter?
matter, mass, weight, volume, density

Physical proprieties of matter are properties that can be measured or observed without changing the chemical makeup of the matter. Examples include size, shape, color and texture.

Remember all matter take up space and have mass.

Matter //Students will learn that matter is anything that has mass and takes up space//.
 * Matter** is everything around you. Atoms and molecules are all composed of matter. 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 will only find it in a few forms on Earth. Each of those states is sometimes called a **phase**. There are many other states of matter that exist in extreme environments. Scientists will probably discover more states as we continue to explore the Universe.

Mass vs Weight //Students will learn that mass is a measure of the amount of matter in an object and weight is a measure of the pull of gravity on an object.//

To understand the differences we need to compare a few points: 1) Mass is a measurement of the amount of matter something contains, while Weight is the measurement of the pull of gravity on an object.

2) Mass is measured by using a balance comparing a known amount of matter to an unknown amount of matter. Weight is measured on a scale.

3) The Mass of an object doesn't change when an object's location changes. Weight, on the other hand, does change with location.

Volume //Students will learn that volume is a measure of the amount of space an object takes up.//

Density //Students will learn that density is the ratio of the mass of a substance to the volume of the substance.//

Density is an important physical property. Density is the mass of a substance per unit volume. Volume is the amount of space an object occupies. Density (whose most common symbol is the lowercase letter d) is defined as mass per unit volume. Density is calculated by dividing the mass of an object by its volume. This is shown in equation form, as follows: > Density = mass ÷ volume By the way, the lower-case Greek letter rho, ρ, is also used to symbolize density. Oftentimes, the rho shape that a textbook would use looks more like the lower-case letter p. However, a lower-case d is more often used in introductory settings like the one you are currently reading. We can calculate the density of a solid, liquid, or gas. The density of a gas will be dealt with in a later unit, because its density is very sensitive to temperature and pressure. Although the density of liquids and solids do change with temperature and pressure changes, the amount is fairly small. We will ignore these small amounts and act as if all our density problems are at the same temperature and pressure. Note the difference in units in the formulas of the density of a solid and liquid. The unit for cubic centimeters is cm3 and for milliliters is mL. > solids: d = grams ÷ cubic centimetersliquids: d = grams ÷ milliliters Since one mL equals one cm3, there is no functional difference between g/cm3 and g/mL. This image will help you in figuring out how to solve density problems: > Simply cover up whichever value you need to calculate and the other two are shown in their proper placement, be it to multiply or to divide. For example, cover up the M. This leave you with dV (ignore the fact that it is in the denominator). Density times volume will give you mass. You can also check it out by way of the units: (g / cm3) x cm3 cancels out the volume unit leaving grams, the desired unit for mass.

An ancient story tells about a Greek king, a gold crown... and an amazing scientist named Archimedes. The king had ordered a solid golden crown made. When the court goldsmiths presented it to him, he asked Archimedes to test it...to make sure it was pure gold. One night, while filling his tub, for a bath, Archimedes accidentally filled it to the very top. As he stepped into it, water spilled out over the top. The idea struck him, that if he collected the water, and measured it, he would know the volume of his body. HE COULD USE THIS TO MEASURE THE CROWN! In other words, the amount of displaced water in the bathtub was the same amount as the volume of his body. Archimedes was able to obtain the volume of the crown and an equal volume of pure gold, from the King’s treasury no doubt. When he placed the two items into separate pans on a two-pan balance…..

Essential Question: What are physical and chemical properties of matter?
physical property, chemical property, conductivity, malleability, solubility, viscosity, luster, ductile, reactivity, flammability

Physical Properties //Students will learn that a physical property is characteristic that can be observed or measured without changing the identity of the substance.//

The measurement of mass and other characteristics that can be seen without changing how that object looks are its physical properties. When you look at oranges, you know that they are oranges because of their color, shape, and smell. Mass, color, shape, volume, and density are some physical properties. The answers to the question about the present are physical properties.

Physical properties of matter are categorized as either Intensive or Extensive:
 * **__Intensive__** - Properties that do not depend on the amount of the matter present.
 * **Color**
 * **Odor**
 * **Luster** - How shiny a substance is.
 * **Malleability** - The ability of a substance to be beaten into thin sheets.
 * **Ductility** - The ability of a substance to be drawn into thin wires.
 * **Conductivity** - The ability of a substance to allow the flow of energy or electricity.
 * **Hardness** - How easily a substance can be scratched.
 * **Melting/Freezing Point** - The temperature at which the solid and liquid phases of a substance are in equilibrium at atmospheric pressure.
 * **Boiling Point** - The temperature at which the vapor pressure of a liquid is equal to the pressure on the liquid (generally atmospheric pressure).
 * **Density** - The mass of a substance divided by its volume
 * **__Extensive__** - Properties that do depend on the amount of matter present.
 * **Mass** - A measurement of the amount of matter in a object (grams).
 * **Weight** - A measurement of the gravitational force of attraction of the earth acting on an object.
 * **Volume** - A measurement of the amount of space a substance occupies.
 * **Length**

Chemical Properties //Students will learn that a chemical property is a property that describes a substance's ability to form new substances.// Chemical properties- These are properties that can only be observed by changing the identity of the substance. A piece of paper burns and turns to a black substance. After the flame goes out, you can no longer burn the new substance. The chemical properties have been changed.

Using Properties to Identify Substances //Students will learn that every substance has characteristic properties.//

Essential Question: What are physical and chemical changes of matter?
physical change, chemical change, precipitate, conservation of mass

Physical Change //Students will learn that a physical change is a change of matter from one form to another without a change in chemical properties.//

Matter is constantly changing. Ice in your soda melts, glass breaks, paper is ripped. When ice in your soda melts where does it go? What does it become? When we discuss phase changes in matter, we are looking at ** physical ** changes. Physical forces alone (unless you're inside of the Sun or something extreme) rarely break down compounds completely. You can apply heat to melt an ice cube, but there will be no change in the water molecules. You can also place a cup of water in a container and decrease the pressure. The water will eventually boil, but the molecules will not change.

If you remember, ice is water in the solid state. If you don't remember this or don't know it, you should go back and review states of water. When you drop the ice cube into the liquid, it begins to melt because the temperature is higher than that of the ice cube. It's like putting a snowman on your front lawn in July. The ice cube becomes liquid water. This is an example of a **physical change**. The solid water turned to liquid water. It doesn't turn into soil or macaroni. It remains water. If it did change into soil or macaroni, your drink would taste terrible and you would have an example of a **chemical change**.

Chemical Change //Students will learn that a chemical change is a change of matter that occurs when one or more substances change into an entirely new substance with different properties.//

Chemical changes in compounds happen when chemical bonds are created or destroyed. Forces act on the bonds between atoms, changing the molecular structure of a substance. Chemical changes are changing substances into other substances. If it could happen, ice changing into macaroni would be an example of a chemical change. A real example of a chemical change is spoiling milk or burning toast. Milk needs to be in the refrigerator or else it will go bad. If you've ever seen or smelled spoiled milk, it is not a pretty sight. The milk gets a sour odor and becomes lumpy. Unlike physical changes, you cannot reverse chemical changes. You can melt ice to get water and freeze that water to get ice again. You cannot make milk unspoiled.

There are millions of different compounds around you. Probably everything you can see is one type of compound or another. When elements join and become compounds, they lose many of their individual traits. Sodium (Na) alone is very **reactive**. But when sodium and chlorine (Cl) combine, they form a **non-reactive** substance called sodium chloride (table salt, NaCl). New compounds have few or none of the physical or chemical traits of the original elements. They have a new life of their own.

Law of Conservation of Mass //Students will learn that mass cannot be created or destroyed in ordinary chemical and physical changes//.

Essential Question: What happens when matter changes state?
Changes in States of Matter //Students will learn that the particles that make up matter are constantly in motion. The arrangement and motion of these particles affect the properties of mater in solids, liquids, and gasses.//

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 fluidy, can move around a little, and fill up containers. Gases are always around you, but the molecules of a gas are much farther apart than the molecules in a liquid. If a gas has an odor, you’ll be able to smell it before you can see it. A material will change from one state or phase to another at specific combinations of temperature and surrounding pressure. Typically, the pressure is atmospheric pressure, so temperature is the determining factor to the change in state in those cases. Names such as boiling and freezing are given to the various changes in states of matter. The temperature of a material will increase until it reaches the point where the change takes place. It will stay at that temperature until that change is completed.

=Changing States of Matter=



Molecules can move from one physical state to another and not change their basic structure. Oxygen (O2) as a gas has the same chemical 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.

The states of matter are Bose-Einstein Condensates, solid, liquid, gas and plasma. Since there is some debate on whether Bose-Einstein condensates and plasma should be classified as a state of matter and since they are not commonly experienced, we will not discuss their properties here.

When heat is applied to a material, its change in state typically goes from solid to liquid to gas. There are some exceptions where the material will go directly from a solid to a gas.

When a material is cooled, its change in state typically goes from gas to liquid to solid. There are some exceptions where the material will go directly from a gas to a solid.

Names of changes
Each change in the state of matter has a specific name.
 * ==== Start from: ==== || ==== Change to: ==== || ==== Name ==== ||
 * solid || liquid || **melting** ||
 * liquid || solid || **freezing** ||
 * liquid || gas || **boiling** ||
 * gas || liquid || **condensation** ||
 * solid || gas

(skipping liquid phase) || **sublimation** ||
 * gas || solid

(skipping liquid phase) || **deposition** ||

Change in temperature
When a material reaches the temperature at which a change in state occurs, the temperature will remain the same until all the energy is used to change the state.

Conservation of Mass During Changes in State //Students will learn that mass is not changed when a substance undergoes a change of state.//

The Law of **Conservation of Mass** dates from Antoine Lavoisier's 1789 discovery that **mass** is neither created nor destroyed in chemical reactions. In other words, the **mass** of any one element at the beginning of a reaction will equal the **mass** of that element at the end of the reaction. ==

==

Essential Question: How do pure substances and mixtures compare?
atom, element, compound, molecule, mixture, pure substance, homogeneous, heterogeneous, solution

How do Particles Combine? //Students will learn that all matter is composed of particles called atoms//. Matter is another word for the stuff things are made of. Everything around us is made of matter, from the air we breathe to the water we drink—even our own bodies. Planet Earth is made of matter, and so are all the stars, planets, and moons in the universe. All matter is made up of tiny particles called atoms. Matter takes on different forms depending on how the atoms are arranged. We call these forms “states of matter”. On Earth, the most common states are solids, liquids, and gases.

Even though many super-tiny atomic particles exist, you only need to remember the three basic parts of an atom: electrons, protons, and neutrons. What are electrons, protons, and neutrons? Electrons are the smallest of the three particles that make up atoms. Electrons are found in shells or orbitals that surround the nucleus of an atom. Protons and neutrons are found in the **nucleus**. They group together in the center of the atom. That's all you have to remember. Three easy pieces!

Pure Substances: Elements and Compounds //Students will learn that elements and compounds are both considered pure substances.// There are almost 120 known elements in the periodic table. Chemists and physicists are trying to make new ones every day in their labs. The atoms of different elements have different numbers of electrons, protons, and neutrons. Every element is unique and has an atomic number. That number tells you the number of protons in every atom of the element. The atomic number is also called the proton number.


 * Molecule** is the general term used to describe any atoms that are connected by chemical bonds. Every combination of atoms is a molecule. A compound is a molecule made of atoms from different elements.

Mixtures: Homogeneous and Heterogeneous //Students will learn that unlike elements and compounds, mixtures are not pure substances//.

A **solution** is a homogeneous mixture in which one substance is dissolved in another substance. In a solution, two or more substances are uniformly mixed. The solution formed is the same in all parts. In a sugar-water solution, molecules of sugar are evenly spread throughout the molecules of water. Solutions consist of two parts: the solute and the solvent. The **solute** is the substance being dissolved. The **solvent** is the substance in which a solute is dissolved. The the sugar-water solution, sugar is the solute and the water is the solvent. The substance present in the largest amount is usually called the solvent. The most common solutions are those in which the solvent is a liquid. The solute can be a solid, gas or liquid. A solution with water as the solvent is called an **aqueous solution**. Water is considered to be a **universal solvent**. Another common solvent is alcohol. A solution with alcohol as the solvent is called a **tincture**. However, other types of solutions can be formed.
 * **Types of Solutions** ||
 * **Solvent** || **Solute** || **Example** ||
 * liquid || liquid || antifreeze ||
 * ^  || solid || sugar water ||
 * ^  || gas || soft drink ||
 * gas || liquid || humidity ||
 * ^  || solid || mothballs ||
 * ^  || gas || air ||
 * solid || liquid || dental fillings ||
 * ^  || solid || steel ||
 * ^  || gas || gas stove lighter ||

The Solution Process
When sugar is added to water, a solution forms. The dissolving action takes place on the surface of the crystal. Water molecules surround the surface molecules of sugar. The sugar molecules are held together only by weak bonding forces. The sugar molecules are attracted more to the water molecules than to each other. surround by water molecules, surface sugar molecules are carried away from the crystal surface. the process of diffusion causes the sugar molecules to distribute evenly within the water molecules. As the outer layer of molecules dissolves, the next layer is exposed to the water molecules. This process continues until all the sugar molecules are separated from each other and mixed evenly throughout the solution. Check out this animation to see how salt dissolves in water.

Solutions can be classified as saturated, unsaturated, or supersaturated. A saturated solution is a solution that contains all the solute it can possible hold at a given temperature. If additional solute is added to a saturated solution, it will settle undissolved to the bottom of the solution. Saturation is dependent on temperature. A solution that contains less solute than this amount is called unsaturated. An unsaturated solution can range from dilute to concentrated. A dilute solution contains very little solute. A concentrated solution contains a large amount of solute. Because these terms are not precise, you can refer to a wide range of actual concentrations.

In some cases you can make a supersaturated solution. This is a solution in which the solvent can hold more solute than normal. You make a supersaturated solution at a high temperature and then cool it very slowly. At room temperature, it will contain more solute than could normally dissolve at that temperature. This type of solution is very unstable. If the solution is not disturbed, all the solute will stay dissolved. If the smallest amount of solute is added to the supersaturated solution, the excess solute comes out of the solution and settles to the bottom. Only enough solute to make the solution saturated remains dissolved.

Rate of Solution
When a solution is stirred, particles of the solute move away form the crystal surface at a higher rate. This exposes more particles to the solvent sooner. Thus the solute dissolves at a faster rate. 2. Solution action occurs only at the surface of the solid solute. So if the surface area of the solute is increased, the rate of solution is increased. More solute molecules are in contact with the solvent when the solid solute is ground into a find powder. 3. If heat is applied to a solution, the molecules move faster and farther apart. As a result, the dissolving action is speeded up. Water is the most common substance on the earth. Water plays an important role in dissolving a great variety of substances. Because thousands of substances are soluble in water, water is sometimes called the universal solvent. However, you should also remember, that there are certain substances that will not dissolve in water. These substances are described as insoluble.

Solubility Factors
The solubility of a solute is a measure of how much of that solute can be dissolved a given amount of solvent under certain conditions. Two main factors that affect the solubility of a solute are temperature and pressure. Generally, an increase in the temperature of a solution increases the solubility of a solid in a liquid. The solubility of most solids is increased by raising the temperature of the solution. Raising the temperature of a gas-in-liquid solution decreases the solubility of the gaseous solute. Thus, the solubility of a gas is decreases as the temperature of the solution increases. For solid and liquid solutes, increases and decreases in pressure have practically no effect on solubility. For gases dissolved in liquids, an increase in pressure increases solubility and a decrease in pressure decreases solubility.