Chemistry and Measurements: Equalities, Conversions, and Density

This set of vocabulary flashcards covers key concepts from Chapter 2 of 'Chemistry: An Introduction to General, Organic, and Biological Chemistry', including units of measurement, conversion factors, density, and specific gravity.

Equality

Uses two different units to describe the same measured amount; written for relationships between units of the metric system, U.S. units, or between metric and U.S. units.

Conversion Factors

Any equality written as fractions used to change from one unit to another.

Exact Numbers (in Equalities)

Numbers obtained by definition, such as those in any equality between two metric units or two U.S. system units, which do not determine significant figures.

1 in. = 2.54 cm

An equality between metric and U.S. units that has been specifically defined as an exact relationship, meaning $2.54$ is an exact number.

Percent Factor

A factor that gives the ratio of the parts to the whole, using the same unit in both the numerator and denominator and the value of $100$.

Density

A comparison of the mass of an object to its volume, describing how tightly packed matter is or the amount of mass in a given space ($\text{Density} = \frac{\text{mass}}{\text{volume}}$).

Density of Solids and Liquids (Units)

Commonly expressed as $g/cm^3$ or $g/mL$.

Density of Gas (Units)

Commonly expressed as $g/L$.

Volume

The three-dimensional space a gas, liquid, or solid occupies.

Volume Displacement

A method to calculate the volume of a solid by measuring how much the level of water rises in a graduated cylinder after the object is added.

Specific Gravity ($sp\,gr$)

A unitless relationship between the density of a substance and the density of water (calculated at $4\,^{\circ}\text{C}$ which is $1.00\,g/mL$).

Hydrometer

A tool used to measure the specific gravity of urine, which has a normal range of $1.003$ to $1.030$.

Osteoporosis

A condition of severe thinning of bone due to the loss of bone minerals, resulting in lower bone density.

Density of Human Fat vs. Muscle

The density of human fat is approximately $0.917\,g/cm^3$, while muscle is denser at $1.06\,g/cm^3$.