Chemistry UNIT1+2

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Matter

anything that has mass or volume

What are the three most common phases of matter?

Solid, Liquid, Gas

Why do solids, liquids, and gases have the shape they do?

Their molecular structure. In a gas the molecules are very far away and move fast, and have lots of energy. In a liquid the molecules are more compact but their is still some distance and movement between molecules, but definitely less the gases. Then in a solid the molecules are compact and vibrate against each other.

Law of Conservation of Matter

When matter converts from one type to another, or changes form, there is no detectable change in the amount of matter present.

What is matter made of?

Matter is made of atoms, the smallest part of an element that retains in properties unless their is a nuclear reaction.

What are molecules and compounds?

One or more atoms chemically bonded together in consistent ratios.

What are the two forms of matter?

Pure Substances and Mixtures.

What is a pure/elemental substance?

A group of atoms that creat only one element.(like gold)

What is a mixture?

A group of atoms bound together that creat more that one element.(like table salt)

What are the two types of mixtures?

Homogeneous and Heterogeneous.

What is the difference between a heterogeneous and homogeneous mixture?

A homogeneous mixture is uniform throughout, like a solution. A heterogeous mixture is not uniform throughout, like a block of pressed wood.

What is chemistry?

Chemistry is the study of changes in matter.

What are the three types of changes in chemistry?

Nuclear, Chemical, and Physical.

What is a nuclear change?

Alters the identity of the element by changing the atoms.

What is a chemical change?

Alters the identity of the chemicals by changing the bonds within the molecules.

What is a physical change?

Does not alter identity but may alter physical appearance, by changing the attraction between molecules.

When does a physical change occur?

When a chemical changes state but doesn’t change its chemical composition.

What are the two types of physical changes?

Phase and shape.

What is a phase change?

Going from solid to liquid to gas.

What is a shape change?

A change in the appearance of matter.

What are the main phase changes?

Freezing(L-S), melting(S-L), vaporization(L-G), condesation(G-L), depostion(G-S), and sublimation(S-G).

When do chemical changes occur?

When a substance changes into something new. You can tell if a chemical change occurs by a change in density, melting point, or freezing point, from the original substance.

What are the four indications of a chemical reaction?

Formation of gas, formation of precipitate, change in color, change in energy(light, heat, or sound).

What are the physical properties of matter?

Extensive and intensive.

What are the intensive properties of matter?

Do not depend on the amount of matter present, like color, density, and boiling point.

What are the extensive properties of matter?

Do depend on the amount of matter present, like mass and volume.

What are the Chemical Properties of matter?

Describe the way a substance can change or react, to form other substances.

What is density?

Density is mass over volume.

Solids = g/cm³

Liquids = g/mL

Gases = g/L

What is the difference between accuracy and precision?

Accuracy shows how far apart your answers are from one another, precison shows how accurate your answers are to a target number.

What is uncertainty?

When measuring a number, there is always uncertainty present because you will only be as close to the real number as your measuring utencil will allow you to be.

Therefore, attatch a +or-0.1 or 0.01 or to whatever degree the answer is uncertain.