Honors Chemistry: Key Concepts and Periodic Table Trends

What is the difference between accuracy and precision in scientific measurement?

Accuracy refers to how close a measurement is to the accepted value, while precision refers to how close repeated measurements are to each other.

What are the rules for significant figures?

Nonzero digits are always significant; zeros between nonzero digits are significant; leading zeros are not significant; trailing zeros after a decimal are significant.

How many significant figures are in the number 0.00450?

3 significant figures (4, 5, and the trailing 0).

What is the format for scientific notation?

Scientific notation is expressed as a × 10^n where 1 ≤ a < 10.

Convert 72,500 to scientific notation.

7.25 × 10^4.

What is an independent variable in an experiment?

The independent variable is the manipulated variable.

What is a dependent variable in an experiment?

The dependent variable is the measured outcome.

What is matter?

Matter is anything that has mass and volume.

What are pure substances?

Pure substances include elements and compounds.

What is a homogeneous mixture?

A homogeneous mixture is uniform in composition, like salt water.

What is a physical property?

Physical properties include color, density, melting point, boiling point, and conductivity.

What is a chemical change?

A chemical change involves a transformation that alters the chemical composition, such as burning wood.

What is the definition of an isotope?

Isotopes are atoms of the same element that have different numbers of neutrons.

What is a cation?

A cation is a positive ion formed by the loss of electrons.

What is the significance of valence electrons?

Valence electrons determine an atom's bonding behavior.

What are the main groups of elements in the periodic table?

Group 1: Alkali Metals, Group 2: Alkaline Earth Metals, Group 17: Halogens, Group 18: Noble Gases.

What happens to atomic radius across a period?

Atomic radius decreases across a period.

What is an ionic bond?

An ionic bond is formed between a metal and a nonmetal through electron transfer.

What is the formula for density?

Density = Mass ÷ Volume.

What is a solute?

A solute is the substance that is dissolved in a solution.

What is cohesion in relation to water?

Cohesion is the attraction between water molecules.

What is the pH range for acidic solutions?

The pH range for acidic solutions is 0-6.

What is the law of conservation of mass?

The law states that atoms cannot be created or destroyed in a chemical reaction.

What is a neutralization reaction?

A neutralization reaction is when an acid and a base react to form a salt and water.

What is the molar mass of water (H₂O)?

The molar mass of water is 18.02 g/mol.

What is the definition of a chemical reaction?

A chemical reaction involves the transformation of substances into new products.

What is the electron configuration for oxygen?

Oxygen's electron configuration is 1s² 2s² 2p⁴.

What is the significance of hydrogen bonding in water?

Hydrogen bonding is responsible for many of water's unique properties, such as high specific heat and surface tension.