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9/23 NOTES Properties of Matter
PHYSICAL PROPERTIES
Physical properties can be observed or measured without changing the matter’s identity.
- Physical properties can be intensive or extensive.
- An intensive property does not depend on the size or amount of matter in the object
- An extensive property does depend on the size or amount of matter
- Physical properties are referred to as observables because you can often "see" the properties.
- * Physical properties can be measured without changing the chemical's identity. The freezing point of a substance is physical. When water freezes, it's still H2O.
EXAMPLES
*Density describes the relationship between mass and volume. It is the amount of matter in a given space.
In terms of g/mL or g/cm3.
D = m / V
CHEMICAL PROPERTIES
Chemical properties are any quality that can be discovered only by changing a substance's chemical identity
- Chemical properties cannot be determined just by viewing or touching the substance; the substance's internal structure must be changed for its chemical properties to be investigated.
- * Chemical properties deal with how one chemical reacts with another. We know that wood is flammable because it becomes heat, ash, and carbon dioxide when heated in the presence of oxygen.
Flammability
Acidity
Reactivity
Toxicity
Oxidation
Heat of Combustion
Characteristic Property - property that defines a substance, used to identify a substance
9/15 NOTES Matter and Classification
Matter--- is anything that has mass and volume
Mass--- the amount of matter (stuff) in an object; measured in kg but we will use g
Weight--- the measure of the gravitational force exerted on an object; this value changes with the location of the object
Volume--- the amount of space an object takes up, an object cannot share the same space as another object at the same time; measured in mL.
Classification---categorization of objects into defined groups based on identified characteristics or properties
NOTES States of Matter
Bose-Einstein Condensate: Super-cooled solid
Plasma: A plasma is when the gas is heated to a very high temperature. Some of the electrons around the atoms are stripped away and the particles become positively charged ions! Some examples where plasma is found include stars, plasma TVs, fluorescent lights, lightening, and the sun.
Click on the image to see it in motion!!!
CHANGES OF STATES OF MATTER
When a state of matter gains or loses heat it undergoes a change.
*A gain in heat is called an endothermic change. A loss in heat is called an exothermic change.
The table below summarizes the six changes of states that matter can undergo and tells you if heat is added or removed for the change to take place.
The red arrows shows when heat/energy is entering the system.
The blue arrows shows when heat/energy is exiting the system.
The following is REVIEW (except for deposition!!!)
Vaporization: when a liquid vaporizes and becomes a gas due to the entering of heat or energy, this includes boiling and evaporating.
Condensation: when gas cools down and condenses into a liquid.
Solidification: when a liquid becomes a “solid” (solidifies) as heat leaves the system.
Melting: when a solid melts (the attractive forces weakens) into a solid due to the addition of heat or energy.
Sublimation: when a solid heats up into a gas. The solid is probably frozen or very cold, the word “sub” represents under, such as “sub-zero.” Dry ice is a sub-zero substance. Dry ice is made of frozen carbon dioxide. Carbon dioxide is a gas at room-temperature so when we put frozen carbon dioxide into room temperature it wants to change directly into a gas; it sublimes.
Deposition: is when a gas loses a high amount of temperature into a solid. One good example is volcanic gas. The gas is really hot when it comes from an erupted volcano, however the temperature of the air is really cold compared to the gas from the eruption. So the gas quickly cools into ash and “deposits.”
The Particle Theory of Matter:
1. Matter is made up of tiny particles (Atoms & Molecules)
2. Particles of Matter are in constant motion.
3. Particles of Matter are held together by very strong electric forces.
4. There are empty spaces between the particles of matter that are very large compared to the particles themselves.
5. Each substance has unique particles that are different from the particles of other substances.
6. Temperature affects the speed of the particles, the higher the temperature, the faster the speed of the particles.
Chemical and Physical Changes
In a physical change, the substance still retains its original properties.
- A change in size (e.g., shredded paper), shape (e.g., molding clay), or state (solid to a liquid, liquid into gas, etc...) is a physical change, as long as the identity of the substance is unchanged.
- Dissolving a substance (e.g., sugar) into another substance (e.g., water) to form a solution (sugar water) is a physical change. SOLUBILITY
- Mixing substances and the substances remain unchanged is a physical change.
Physical Change - a change that alters the APPEARANCE of a material but does not make the material into another substance
- Physical changes are REVERSIBLE
- Example of Physical Change: If we rip a piece of paper, the color is the same. The paper is still a solid state of matter. The paper is still smooth. The pieces of paper maybe put back together and look the same.
- Other Examples:
- tearing paper
- chopping wood
- molding clay
- melting ice
- breaking glass
- cutting wire
- painting wood
- boiling water
A change in the state of matter is a PHYSICAL CHANGE.
In a chemical change, atoms rearrange and form one or more new substances.
Examples of evidence that a chemical change has occurred are:
- a change in temperature
- the formation of a gas
- a change in color
- the formation of a gas
- a change in color
- light given off
A chemical change (usually) cannot be reversed.
Reactivity --- when two or more substances combine and create a new substance
Chemical Change - a change in matter that PRODUCES A NEW SUBSTANCE
- A chemical change is irreversible.
- A chemical change changes the matter’s color, its odor, and forms it into something new, it is a chemical reaction.
- A chemical reaction is when two or more substances combine and become something new. The changes that occur depends on the chemical properties.
- Signs that a chemical change has taken place:
- bubbles appear - release of gas
- precipitate forms - two liquids for a solid
- color change
- light is emitted
- temperature change
- change in smell or taste
Energy is ALWAYS involved during BOTH physical and chemical changes
Examples of chemical changes:
- Tarnishing
- Rusting
- Cooking (where you make a new substance!)
- Rotting
- Digesting
- Burning
- Souring milk
- Molding Cheese
- Photosynthesis
- Exploding fireworks
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