Matter and Its Changes Chemistry 11

Observation vs. Interpretations Observations: The use of all the senses (sight, taste, smell, hearing, and touch) to gather information from and about your surroundings. Interpretations: Is the inference based on an observation. Brings meaning to an observation. 2 types: 1.Qualitative information is non-numerical information. Things you see. 2.Quantitative information is numerical information. Things you measure.

For example: ObservationQualitative Description Quantitative Description

Matter and Its Phases Matter: Anything that has mass and occupies space. Matter is “anything that has mass” means that matter is anything that has inertia and requires a force to get it moving or stopped.

What’s the MATTER?

Solids Generally rigid. Particles are closely packed into a given volume in a highly organized and rigid manner. Requires particles to be in direct contact with one another. Have their own shapes. Not compressible. Their volume only changes slightly in response to changes in temperature and pressure.

Liquids Take the shape of the container. Particles remain in close contact with each other, but have sufficient room to slide past one another easily. Do not have an organized packing. Not compressible. Their volume changes very little in response to temperature and pressure changes.

Gasses Completely fill container The particles are widely separated and only contact each other during collisions. Very compressible. Their volume is drastically changed by temperature and pressure.

The fourth state of matter is called PLASMA Plasma has all the properties of a gas except that is composed of charged particles They exist on stars (the sun), in nuclear explosions, and in neon signs.

Particle Movement Particles in the three phases can exhibit three types of movement: Vibrational Vibration of the particle. Rotational Spinning of the particle. Translational Movement of the particle in a straight line.

Solids Vibrational movement only Liquids Vibrational, rotational, and translational motion Gasses Translational movement only.

As we increase the average kinetic energy (temperature) of the particles, the matter changes to a higher energy phase.

Chemical and Physical Changes Chemical Change: A change in which new substances are formed Produces a set of chemicals which is different from the set of chemicals which existed before the change.

Examples include: Noticeable heat or light is produced. A colour change is observed Bubbles of gas may appear, which shows that a new gas may be forming. Cloudiness may result; this shows that a solid is forming (a precipitate).

Physical Change: A change in the phase of a substance, such that no new substances are formed. A physical change does not change the set of chemicals involved. WATER  ICE Chemical changes are often accompanied by physical changes.

Physical Property Any aspect of an object or substance that can be measured or perceived without changing its identity. Can be either: Intensive: A physical property which depends solely on the nature of the substance, NOT the amount of substance present. Used to identify a substance. Examples: Density, melting temperature, viscosity

Extensive: A physical property which depends on the amount of the substance present. Examples: Mass, Volume, Length, Energy.

Perceptions Certain perceptions are often described (or even “measured”) as if they are intensive or extensive physical properties. In fact, perceptions are fundamentally different from physical properties. They are based on an observers response.

Huh? Examples of perceptions related to an intensive physical property: Temperature: in this case all observers will agree which is the hotter of two objects. Examples of perceptions related to an extensive property: Colour of a solution: The related physical property is the transmission or absorption spectrum.

Homework Do W.S. 2-3

The Kinetic Molecular Theory The Kinetic Molecular Theory explains the forces between molecules and the energy that they possess. Energy: Anything that is not matter and can cause a change in matter. During any energy conversion, there is no loss or gain of energy. The forms of energy change constantly, but the amount of energy remains constant.

Potential Energy: Energy stored within a physical system. It has the “potential” to be converted to different forms of energy, and to do work in the process. Kinetic Energy: The energy an object posses due to its motion. Where: m = mass v = velocity

Changes in State By heating or cooling matter, we can change the state in which it is in. Transitions between phases are called CHANGES IN STATE. There are several temperature points where significant changes to matter take place.

Melting Temperature The temperature where a solid changes to a liquid. Freezing Temperature The temperature where a liquid changes to a solid. At the MELTING/FREEZING TEMPERATURE, the solid and liquid phases co-exist.

Boiling Temperature The temperature where a liquid changes to a gas. Condensation Temperature The temperature where a gas changes to a liquid. At the BOILING/CONDENSATION TEMPERATURE, liquid and gas phases co-exist.

Sublimation Decrease in pressure and increase in temperature Deposition Increase in pressure and decrease in temperature

Activity! Groups of 3! What you need… Hot plate 600mL beaker Thermometer 400 mL of Ice Heat ice on med temperature recording the temperature every 30 seconds. DO NOT STIR WITH THERMOMETER DO NOT LET THERMOMETER TOUCH BOTTOM OF BEAKER

In general, continued heating of a solid produces the following temperature behaviour: The temperature does not change during a phase change (such as melting and boiling).

What’s on the Test? Lab safety Hazardous Household Product Symbols WHMIS Classes Symbols MSDS Sheet’s PPE’s Matter and It’s Phases Solids, Liquids and Gasses The Kinetic Molecular Theory Changes in state Definitions Heating Curves