Chem 60 Ch3 Matter & Energy

Is the quantity of heat (usually joules) required to change the temperature of a given amount of the substance by 1 degree Celsius.

Heat capacity of a substance

Immiscible: Do not mix - can separate immiscible liquids by decanting Ex: oil and water Miscible: (of liquids) forming a homogeneous mixture when added together - can separate mixtures of miscible liquids by distillation

Immiscible & Miscible

The total energy of a sample of matter is the sum of it s kinetic energy, the energy associated with its motion.

Kinetic energy

Atomic/Molecular motion: Free to move relative to one another Atomic/Molecular Spacing: Close together Shape: Indefinite - takes shape of its container Volume: Definite - doesn't adjust its V to container Compressibility: Incompressible Atoms or molecules are close to each other - about as close as molecules in a solid), but they are free to move around and past each other. Ex: Water - Gasoline - Alcohol - Mercury

Liquid Matter

Anything that occupies space and has mass. Space = volume So all matter has density, because if you have volume and mass you can find its density: D=m/V

Matter

1. Pure Substance: a substance composed of only one type of atom or molecule. Pure form of matter. - Elements & Compounds 2. Mixture: a substance composed of two or more different types of atoms or molecules combined in viable proportions. - Homogeneous & Heterogeneous Composition: The nature of something's ingredients or constituents; the way in which a while or moisture is made up.

2 Types of Composition of Matter (Second way to classify matter - First way is by state)

1. Heterogeneous mixture: made out of two or more phases. the composition varies from one region to another. - is a mixture where the components of the mixture are not uniform or have localized regions with different properties. Different samples from the mixture are not identical to each other. There are always two or more phases in a heterogeneous mixture, where you can identify a region with properties that are distinct from those of another region, even if they are the same state of matter (e.g. Liquid, solid). - Usually it's possible to physically separate components of a heterogeneous mixture. Ex: you can centrifuge (spin out) solid blood cells to separate them from the plasma of blood. You can remove ice cubes from soda. You can separate candies according to color. Ex: oil and water - Soil - Apple juice with pulp - ice cream float - cereal in milk - vegetable soup - pizza - blood - gravel - ice in soda - salad dressing - mixed nuts - bowl of colored candies 2. Homogeneous mixture: made out of one phase (be it liquid, gas or solid phase). The composition is the same throughout. They have uniform compositions because the atoms or molecules that compose them mix uniformly. - a mixture where the components that make up the mixture are uniformly distributed throughout the mixture. The composition of the mixture is the same throughout. - you can't pick out components of a homogeneous mixture or use a simple mechanical means to separate them. You can't see individual chemicals or ingredients in this type of mixture. Only one phase of matter is present in a homogeneous mixture. Ex: salt water - sweetened tea - hot coffee - Air - sugar water - rain water- vodka - vinegar - dishwashing detergent - steel

2 Types of Mixtures

1. Crystalline Solid: atoms or molecules occupy specific positions to create a well-ordered, three-dimensional structure; arranged in geometric patterns with long-range, repeating order. Ex: Salt (sodium chloride) - Diamond 2. Amorphous Solid: atoms or molecules don't have long-range order. Ex: Glass - Rubber - Plastic

2 Types of Solid Matter

Solid - Liquid - Gas - (Plasma) State: a physical condition that something is in at a specific time as regards to molecular form or structure.

3 (4) States of Matter (First way to classify matter, by states)

Refers to how close a measurement is to the true value. - ACcurate is Correct. (or Close to real value) IOS refers to accuracy as meaning has not systematic or random error, which is really to have both accuracy and precision. Accuracy means getting a result that is close to the real answer. (Precision means getting a similar result every time you try.) - Think of shooting at a target: Being accurate means you hit the bull's eye. (Being precise means hitting the same spot on the target every time.) - Accurately hitting the target means you are close to the center of the target, even if all of the marks are on different sides of the center. If the player always makes a basket, even though he strikes different portions of the rim, he has a high degree of accuracy. If your scale gives you values of 49.8, 50.5, 51.0, 49.6, it is more accurate than the first balance, but not as precise. - The more precise scale would be better to use in the lab, providing you made an adjustment for its error.

Accuracy

The capacity to do work. - virtually all samples of matter have energy

Energy

Chemical reactions that release energy.

Exothermic

The action or process of filtering something. - If a mixture is composed of a solid and liquid, we can separate the two by filtration, in which we pour the mixture through filter paper usually held in a funnel.

Filtration

Atomic/Molecular motion: Free to move relative to one another Atomic/Molecular Spacing: Far apart Shape: Indefinite - takes shape of container Volume: Indefinite - takes V of container Compressibility: Compressible Atoms or molecules are separated by large distances and are free to move relative to one another. Gases always assume the shape & volume of their containers. Because the atoms or molecules that compose gases are not in contact with one another, gases are compressible. Ex: putting air in a tire, we push more atoms and molecules into the same space, compressing them and making the tire harder. Ex: Oxygen - Helium - Carbon dioxide

Gas Matter

Is the transfer or exchange of thermal energy caused by a temperature difference. - it has units of energy. - it is not to be confused with temperature, which is the measuring of thermal energy.

Heat

Properties that a substance displays without changing its composition. - the atomic or molecular composition of a substance doesn't change when the substance displays its physical properties. Ex: Odor - taste - color - appearance - melting point - boiling point - density (1L has a mass of 1.260g under standard conditions) - temperature (gas at room temp) - Mixes with acetone - Odor of gasoline, it doesn't change its composition when it exhibits its odor - boiling point of water at 100C, it changes from liquid to gas, but the gas is still water, the water molecules are the same in both the liquid and gaseous steam

Physical Property

Of a solid substance, change directly into vapor when heated, typically forming a solid deposit again on cooling. - physical change

Sublime

A measure of its thermal energy

Temperature of a substance

The more easily vaporizable - of a substance, easily evaporated at normal temperatures.

Volatile

Result of a force acting on a distance.

Work

When the amount of the substance is expressed in grams, the heat capacity is called the specific heat capacity (specific heat). - has units of joules per gram per degree Celsius (J/g C).

Specific Heat

gradually pour from one container into another, especially without disturbing the sediment. Ex: Carefully pouring off the oil on top of the water into another container.

Decanting

The action of purifying a liquid by a process of heating and cooling. - heat the mixture to boil off the more volatile liquid.

Distillation

Is the energy associate with the flow of electrical charge.

Electrical energy

Chemical reactions that absorb energy from their surroundings as they occur.

Endothermic

Submicroscopic particles that are the fundamental building blocks of matter.

Atoms

Matter does change its composition. - results in a completely new substance. - changes involving chemical reactions are always chemical changes, such as heat exchange or color changes. - rearrange and get new atoms or molecules. Can't get back original atoms or molecules. Atoms doe change their fundamental associations, resulting in matter with a new identity. Ex: copper turning green with cont. exposure to air, forming a new compound

Chemical Change

Properties that a substance can display only through changing its composition. Ex: corrosiveness - flammability - acidity - toxicity - polymerizes to form polyethylene - Flammability of gasoline, it changes its composition when it burns - the susceptibility of iron to rust is a chemical property, and rusting is a chemical change when iron rusts it turns from iron into iron(III) oxide

Chemical Property

The process by which one or more substances transform into different substances via a chemical change. - Chemical reactions often emit or absorb energy. - Matter undergoes a chemical change when it undergoes a chemical reaction.

Chemical Reaction

A form of potential energy associated with the positions of the particles that compose the chemical system. Ex: the molecules that compose gasoline contain a substantial amount of chemical energy. It's released upon burning.

Chemical energy

Composed of two or more different types of atoms or molecules combined in viable proportions; mixtures may be composed of two or more elements, two or more compounds, or a combination of both. Majority of matter that we encounter are mixtures. Ex: Apple juice - Flame - Salad dressing - Soil Each contain several substances with proportions that vary from one sample to another. Ex of other common mixtures: Air - Seawater - Brass Air is composed primarily of Nitrogen and oxygen gas. Seawater is composed primarily of salt and water. Brass is composed of copper and zinc. Each of these can have different proportions of its constituent components. Ex: the metal properties in brass, can be tailored to vary the amounts of zinc and copper for its indeed use - the higher the zinc content relative to the copper content, the more brittle the brass.

Mixture of matter

Two or more atoms joined to one another in specific geometric arrangements; atoms bonded together to form molecules.

Molecules

Matter changes its appearance but not its composition. - results in a different form of the same substance. - Changes in state are always physical changes, such as melting or boiling, or changes that involve merely appearance, such as cutting or crushing. - Can get/put back together, rearrange but have same thing still. The atoms that oppose the matter do not change their fundamental associations, even though the matter may change its appearance. Ex: Ice melting to water - glass shattering - sublime

Physical Change

The energy associated with its position or composition

Potential energy

Is how consistent results are when measurements are repeated. Precise values differ from each other because of random error, which is a form of observational error. - PRecise is Repeating. (or Repeatable) (Accuracy means getting a result that is close to the real answer.) Precision means getting a similar result every time you try. - Think of shooting at a target: (Being accurate means you hit the bull's eye.) Being precise means hitting the same spot on the target every time. - Precisely hitting a target means all the hits are closely spaced, even if they are very far from the center of the target. If he doesn't make many baskets, but always strikes the same portion of the rim, he has a high degree of precision. - A player who throws free throws that always make the basket the exact same way has a high degree of both accuracy and precision. If you take the measurements of the mass of a 50.0 gram standard sample and get values of 47.5, 47.6, 47.5, and 47.7 grams, your scale is precise, but not very accurate.

Precision

The characteristics that distinguish one substance from another. 1. Physical property 2. Chemical property

Properties 2 Types

Composed of only one type of atom or molecule Ex: Helium - Water - Copper - Sugar - The atoms that compose helium are all helium atoms, and the molecules that compose water are all water molecules. No other atoms or molecules are mixed in. 1. Elements: Atoms (Electrons, Protons, Neutrons) - a substance that cannot be broken down into simpler substances. Ex: Gold - Boron - Barium - Aluminum - Sulfur - Copper - Graphite in a pencil, is pure carbon, no chemical transformation can decompose graphite in to simpler substances. 2. Compounds: Molecules - a substance composed of two or more elements in fixed definite proportions. Ex: Distilled water - Water - Sulfur trioxide - Table Salt - Sugar - Methane - Acetone These can all be decomposed onto simpler substances. Heat sugar, it decomposes into carbon (element), and gaseous water (different compound). Compounds are more common than elements because most elements are chemically reactive and combine with other elements to form compounds.

Pure Substance of matter - 2 types

Reactants: in a chemical reaction, the substances present before the chemical change. Products: the substances present after the change. Reactants to (chemical change) to Products

Reactants & Products

Atomic/Molecular motion: Oscillation/vibration about fixed point. Atomic/Molecular Spacing: Close together Shape: Definite Volume: Definite - doesn't take shape of a container Compressibility: Incompressible - because very close together Atoms or Molecules pack close to each other in fixed locations. Neighboring atoms or molecules in a solid may vibrate or oscillate, they don't move around each other, giving solids their familiar fixed volume and rigid shape. Ex: Ice - Diamond - Quartz - Iron

Solid Matter

Matter is neither created nor destroyed in a chemical reaction. - thus the mass of the products of a chemical reaction must be equal to the mass of the starting materials. Ex: gas or butane mass kg + O2 mass = CO2 mass + H2O mass

The law of conservation of mass

Is the energy associated with the random motions of atoms and molecules in matter. -the hotter an object, the more thermal energy it contains.

Thermal energy