APChem Ch.1

What is an atom?

The smallest particle of an element that is indivisible.

What is an element?

A substance that cannot be broken down into a simpler substance.

What defines a compound?

A substance made up of two or more elements bonded proportionally.

What is the Law of Definite Proportions?

A principle stating that a compound always contains the same proportion of elements.

What is a physical process?

A transformation that does not alter the chemical identities of a substance.

What are physical properties?

Properties that can be measured or observed without changing the substance into another substance.

What are chemical properties?

Properties that can only be observed by reacting the substance with another substance.

What is mass?

The amount of matter in an object.

How is density defined?

The ratio of mass to volume.

What are intensive properties?

Properties that are independent of the amount of substance.

What are extensive properties?

Properties that depend on the amount of a substance.

What is a chemical reaction?

The conversion of one or more substances into another one or more substances.

What are chemical bonds?

The force that keeps two atoms or ions together in a molecule or compound.

What is a mixture?

A combination of two or more pure elements that can be separated by physical processes.

What is a homogeneous mixture?

A mixture where the components are distributed evenly and the composition is uniform throughout.

What is a heterogeneous mixture?

A mixture where the components aren’t evenly distributed and have different compositions.

What is distillation?

A process of evaporation and condensation to separate a mixture of substances with different volatilities.

What is filtration?

The process of separating solid particles from a liquid or gas by passing them through a filter.

What is chromatography?

A method that separates components of a mixture based on differing properties using a stationary and mobile phase.

What is a solid?

Matter with a definite volume and shape.

What is a liquid?

Matter with a definite volume but no definite shape; it takes the shape of its container.

What is a gas?

Matter with neither definite volume nor shape; it expands to occupy the entire volume and shape of its container.

What is sublimation?

The transformation of a solid directly to a gas.

What is deposition?

The transformation of a gas directly to a solid.

What is vaporization?

The transformation of a liquid to gas.

What is condensation?

The transformation of gas to liquid.

What is melting/fusion?

The transformation of solid to liquid.

What is solidification?

The transformation of liquid to solid.

What is energy?

The capacity to do work.

What is work?

The exertion of force through a distance.

What is potential energy?

Energy stored in an object due to its composition or position.

What is kinetic energy?

The energy of an object in motion due to its mass and speed.

What is the law of conservation of energy?

Energy cannot be created or destroyed, only converted.

Which elements exist diatomically?

Br, I, N, Cl, H, O, F.

What is a structural formula?

A representation of a molecule showing chemical bonds with lines and symbols.

What is an ionic compound?

A compound that contains positive and negative ions.

What is a molecular formula?

A chemical formula that indicates how many atoms of each element are in one molecule.

What is an empirical formula?

A chemical formula that displays the subscripts with the smallest possible ratio of atoms in a compound.

What is absolute zero?

The zero point on the Kelvin scale and theoretically the lowest temperature possible.

What is precision in measurements?

How repeatable a measurement is.

What is accuracy in measurements?

How close a value is to the true value.

What are significant figures (SigFigs)?

Certain digits in a number that carry meaning contributing to its precision.

What is a conversion factor?

A fraction in which the numerator is equivalent to the denominator but expressed in different units, making the fraction equal to 1.

What is the mean?

An average of all data points, represented by x̄.

What is standard deviation?

A measure of the amount of variation in a value set.

What is a confidence interval?

A range of values that has a specified probability of containing the true value of a measurement.

What is Grubes test?

A test used to detect a single outlier.