Chemistry Fundamentals, Dimensional Analysis, and Temperature Conversions

Flashcards derived from the lecture transcript covering definitions of chemistry and matter, classifications of matter, conversion factors, dimensional analysis rules, significant figures, and temperature conversion formulas.

What is the definition of chemistry?

Chemistry is the study of matter and the changes matter undergoes.

What is matter?

Matter is defined as anything that has mass and takes up space.

How are pure substances characterized?

Pure substances stay constant and cannot be broken down by physical processes.

What is an element?

An element is the simplest form of matter containing only one type of atom, which cannot be broken down.

What is a compound?

A compound is matter formed by chemically bonding two or more elements in fixed proportions, such as water ($H_2O$) or salt ($NaCl$).

What is an equality in measurement?

An equality is a comparison that relates two units that measure the same quantity, such as $12\,\text{inches} = 1\,\text{foot}$ or $3.28\,\text{ft} = 1\,\text{m}$.

What is a conversion factor?

A conversion factor is a ratio derived from the items found inside an equality, used to convert from one unit of measurement to another.

What two conversion factors can be created from the equality $3.28\,\text{ft} = 1\,\text{m}$?

The two conversion factors are $\frac{3.28\,\text{ft}}{1\,\text{m}}$ (used to convert meters into feet) and $\frac{1\,\text{m}}{3.28\,\text{ft}}$ (used to convert feet into meters).

What is the general setup formula for converting units using dimensional analysis?

$$\text{Given Unit} \times \frac{\text{Needed unit}}{\text{Given Unit}} = \text{Needed unit}$$

How do units change when applying addition/subtraction, multiplication, and division in dimensional analysis?

In addition and subtraction, units stay the same; in multiplication, units square (e.g., $3.5\,\text{m} \times 10.0\,\text{m} = 35\,\text{m}^2$); in division, units cancel out.

What is the mass in kilograms of a $193\,\text{lb}$ patient using the equality $1\,\text{lb} = 0.454\,\text{kg}$?

$87.6\,\text{kg}$ (calculated as $193\,\text{lb} \times \frac{0.454\,\text{kg}}{1\,\text{lb}} = 87.619\,\text{kg}$, rounded to $3$ significant figures).

What is the significant figure rule for multiplication and division problems?

The answer must be reported with the same number of significant figures as the number in the calculation that has the least number of significant figures.

What is the significant figure rule for addition and subtraction problems?

The answer must be reported with the same number of decimal places as the number in the calculation that has the least number of decimal places.

What is the formula to convert degrees Celsius ($^\circ\text{C}$) to degrees Fahrenheit ($^\circ\text{F}$)?

$$^\circ\text{F} = 1.8(^\circ\text{C}) + 32$$

What is the formula to convert degrees Fahrenheit ($^\circ\text{F}$) to degrees Celsius ($^\circ\text{C}$)?

$$^\circ\text{C} = \frac{^\circ\text{F} - 32}{1.8}$$

What is the formula to convert degrees Celsius ($^\circ\text{C}$) to the Kelvin scale ($\text{K}$)?

$$\text{K} = ^\circ\text{C} + 273.15$$

What special significant figure rule applies to temperature calculations?

Do not use significant figures for temperature conversions.