7.1 Chemistry Flashcards

Solids

Particles are tightly packed.

Liquids

Particles are moderately spaced.

Gases

Particles are far apart.

Objective Support

Data provides objective support for arguments

Subjective Opinions

Less reliable than objective data.

Scientific Arguments:

Data is useful in comparing different substance combinations.

Molecular Formulas

Show types and numbers of atoms in a molecule.

H₂O

2 hydrogen 1 oxygen

CH4

1 carbon 4 hydrogen

Density

Mass per unit volume

Formula

Density = Mass/Volume

Units

Commonly measured in grams per cubic centimeter

Density and Buoyancy

Denser objects sink, less dense objects float

Volume

The amount of space an object occupies.

Measurement

Volume is often measured in cubic centimeters.

Volume and Mass

Volume is the amount of space an objectoccupies, while mass is the amount of matter it contains.

Physical Change

Does not change the substance's identity.

Chemical Change

Creates new substances.

Energy

Can be transferred to separate molecules.

Endothermic reaction

Adding energy via heat or electricity

Electricity

Can break water molecules into hydrogen and oxygen

Reactions

Certain chemicals react predictably to form gas and other products.

Acids and Bases

Reactions involving acids and bases often produce gases like CO2

Closed System

Mass remains constant during a reaction

Mass Conservation

Mass is converted during the reaction, and all reactants have been converted to products within the closed system.

_H₂ + O₂ → _Н₂O

2 and 2

Temperature

Higher temperatures increase particle speed and pressure

Kinetic Energy

Higher temperatures increase kinetic energy and pressure

Variables

Identifying independent, dependent, and controlled variables ensures fair testing in experiments.

Gas Production

Certain reactions produce gases likе СО₂