Chemistry 105 Lecture Review: Measurement, Calculations, and Atomic Theory

Vocabulary flashcards covering dimensional analysis, significant figures, Dalton's atomic theory, chemical equation balancing, mass percent, and periodic table categories.

Controlling Number

The variable in a question that possesses the least number of significant figures (excluding exact conversion factors), which determines the required number of significant figures in the final calculated answer.

Dalton's Atomic Theory

A foundational theory composed of four basic ideas proposed by John Dalton: elements consist of tiny particles called atoms, all atoms of a given element are identical with identical chemical properties, compounds are formed by combinations of atoms in fixed ratios, and chemical reactions involve only the separation, combination, or rearrangement of atoms.

Adamos

The Greek word meaning a single unit, from which the word 'atom' originates.

Law of Conservation of Matter

An unchangeable statement of fact establishing that matter (and atoms) cannot be created or destroyed in a chemical reaction, providing the theoretical basis for balancing chemical equations.

Coefficient

The number placed directly in front of a chemical formula in an equation to balance the number of atoms, applying to all elements in the formula that follows.

Subscript

The small number written within a chemical formula that establishes the permanent chemical identity and atomic ratio of a compound, which cannot be altered when balancing an equation.

Mass Percent

The proportion of an element's mass within a compound, calculated by dividing the mass of the individual element by the total mass of the sample and multiplying by $100$.

Transition Metals

A row of 10 elements located in the middle section of the periodic table.

Metalloids (Semi-metals)

A group of elements situated along the staircase line on the periodic table (such as silicon) that possess characteristics bridging both metals and nonmetals.

Molecular Compound

A chemically distinct compound formed by the combination of two or more nonmetals.

Ionic Compound

A chemically distinct compound formed by the combination of a metal and a nonmetal (such as aluminum oxide).