Chapter 2-3: Measurements, Units, and Matter & Energy (VOCABULARY Flashcards)

Vocabulary flashcards covering units, measurements, significant figures, prefixes, density, matter and energy, and basic thermodynamics as presented in the lecture notes.

Volume

The amount of space that a substance occupies; common units include liter (L), milliliter (mL); 1 L = 1000 mL; 1 m³ = 1000 L; 1 mL = 1 cm³.

Liter (L)

Metric unit of volume equal to 1000 milliliters; often used for liquids; 1 L ≈ 1.06 quarts.

Milliliter (mL)

Volume unit equal to 1 cm³; commonly used for small volumes.

Cubic centimeter (cc)

Unit of volume equal to 1 mL; 1 cm³ = 1 mL; often used interchangeably with mL.

Meter (m)

SI base unit of length; 1 m = 100 cm; 39.4 inches; 1.09 yards.

Mass

Amount of matter in an object; SI unit is the kilogram (kg); 1 kg = 1000 g; 454 g ≈ 1 lb.

Temperature scales

Scales used to measure hot/cold: Celsius (°C) and Kelvin (K); conversions: °C to °F, K to °C.

Degree Celsius (°C)

Temperature scale where water freezes at 0°C and boils at 100°C.

Kelvin (K)

SI temperature scale with absolute zero as 0 K; 1 K has same magnitude increment as 1°C; conversion: K = °C + 273.

Measured number

A quantity obtained using a measuring tool; includes an estimated final digit.

Estimated digit

The final digit in a measurement that is estimated to the last place of precision.

Significant figures (SFs)

Digits that carry meaningful information about precision; rules determine which zeros are significant.

Leading zeros

Zeros at the beginning of a decimal number; not significant.

Confined zeros (captured zeros)

Zeros between nonzero digits; significant.

Trailing zeros

Zeros at the end of a decimal number; significant; may be non-significant in whole numbers without a decimal.

Exact numbers

Numbers obtained by counting or defined equalities; unlimited SFs and do not limit calculation precision.

Prefixes (increase in size)

Multipliers that increase unit size: tera (10^12), giga (10^9), mega (10^6), kilo (10^3).

Prefixes (decrease in size)

Multipliers that decrease unit size: deci (10^-1), centi (10^-2), milli (10^-3), micro (10^-6), nano (10^-9), pico (10^-12).

Prefix symbol for micro

μ (mu); sometimes written as mc for medical safety to avoid misreading.

Density

Mass per unit volume (D = m/v); affects whether objects sink or float; water density is 1.00 g/mL.

Specific gravity

Ratio of a substance’s density to the density of water (dimensionless); water at 1.00 g/mL is reference.

Pure substance

Matter with fixed composition; includes elements and compounds.

Element

A pure substance consisting of one type of atom.

Compound

A pure substance composed of two or more elements chemically bonded in a fixed ratio.

Mixture

Matter composed of two or more substances physically mixed; can be separated by physical methods.

Homogeneous mixture

Uniform composition throughout; components not visibly distinct (e.g., brass).

Heterogeneous mixture

Nonuniform composition; components are visible (e.g., salad).

Physical property

Characteristic observed or measured without changing composition (e.g., color, density, boiling point).

Chemical property

Ability of a substance to form new substances (e.g., flammability, rusting).

Physical change

Change in appearance or state that does not change composition (e.g., melting, cutting).

Chemical change

Change that forms one or more new substances with new properties (e.g., burning, rusting).

States of matter

Solid, liquid, and gas; each has distinct shapes, volumes, and particle arrangements.

Absolute zero

Lowest possible temperature; 0 K (−273.15°C); at this point particle motion would stop.

Heat

Energy associated with the motion of particles; more motion means more heat.

Joule (J)

SI unit of energy and work; 1 kJ = 1000 J.

Calorie (cal)

Energy to raise 1 g of water by 1°C; 1 kcal = 1000 cal; 1 cal = 4.184 J.

Specific heat (SH)

Amount of heat required to raise the temperature of 1 g of a substance by 1°C; units J/g·°C or cal/g·°C.

Heat of fusion

Energy required to melt 1 g of solid at its melting point (e.g., ice = 80 cal/g or 334 J/g).

Heat of vaporization

Energy required to vaporize 1 g of liquid at its boiling point (e.g., water = 540 cal/g or 2260 J/g).

Sublimation

Phase change from solid to gas without becoming liquid.

Deposition

Phase change from gas to solid without becoming liquid.

Evaporation

Vaporization that occurs at the surface of a liquid, not necessarily at boiling point.

Boiling point

Temperature at which a liquid’s vapor pressure equals atmospheric pressure.

Condensation

Gas to liquid phase change as vapor loses kinetic energy.

Heating curve

Diagram showing temperature changes and phase changes as heat is added.

Cooling curve

Diagram showing temperature changes and phase changes as heat is removed.

Temperature conversion (°C to °F)

F = (C × 1.8) + 32; C = (F − 32) ÷ 1.8.

Temperature conversion (K)

Kelvin to Celsius: C = K − 273; Celsius to Kelvin: K = C + 273.

Energy unit (Calorie to Joule relation)

1 cal = 4.184 J; 1 kcal = 1000 cal.

Scientific notation

Expressing numbers as a×10^n; keeps only significant zeros.

Conversion factor

Equality written as a fraction with units that allows unit cancellation.

Common equalities (length/volume/mass)

Examples: 1 m = 1000 mm; 1 L = 1000 mL; 1 kg = 1000 g; 1 in = 2.54 cm.