Chemistry: A Molecular Approach — Chapter 1: Matter, Measurement, and Problem Solving

A comprehensive set of flashcards covering matter, mixtures, states, changes, energy, measurement, and dimensional analysis from Chapter 1.

What is matter?

Anything that has mass and occupies space.

Approximately how many elements compose all matter on Earth?

About 100 elements.

What is an element?

The simplest form of matter with distinct properties that cannot be broken down chemically.

What is a pure substance?

A substance with uniform properties and composition; includes elements and compounds.

What is an atom?

The smallest unit of an element that retains its properties.

What are chemical bonds?

Attractions between atoms that hold them together in molecules; bonds can be broken to form new ones.

What is a compound?

A chemical combination of two or more elements in fixed proportions; can be decomposed chemically.

How can water (H2O) be decomposed?

By passing an electric current (electrolysis).

What is a molecule?

Two or more atoms bound together.

What is the central goal of chemistry?

To understand the behavior of matter by studying atoms and molecules.

How do graphite and diamond differ?

Both are carbon, but graphite has sheets of carbon; diamond has a 3D network; different structures cause different properties.

What is a mixture?

Two or more pure substances physically combined; not chemically bonded.

What is a heterogeneous mixture?

Not uniformly mixed; two phases visible (e.g., oil and water).

What is a homogeneous mixture?

Uniform composition; one phase; also called a solution.

What is distillation?

Separation of a liquid mixture by boiling off the more volatile component and condensing it.

What is decanting?

Carefully pouring off the liquid from a mixture, leaving the other component behind.

What is filtration?

Separation of a solid from a liquid by passing the mixture through filter paper.

What are the states of matter?

Solid, liquid, and gas.

How do solids differ from other states?

Solids have fixed volume and rigid shape; particles are in fixed positions.

What is crystalline solid?

Solids with long-range, repeating order (e.g., table salt, diamond).

What is amorphous solid?

Solids without long-range order (e.g., glass, plastic).

What are the properties of liquids?

Fixed volume; take the shape of their container; can flow.

What are gases?

Particles move independently with large spaces; they are compressible.

What is a physical change?

A change that alters state or appearance but not composition.

What is a chemical change?

A change that alters chemical composition; atoms rearrange to form new substances.

Is evaporation of rubbing alcohol a physical or chemical change?

Physical change; the substance remains rubbing alcohol.

Is burning lamp oil a physical or chemical change?

Chemical change; combustion.

Is frost formation a physical or chemical change?

Physical change; state change without composition change.

What is a physical property?

A property observed without changing the substance’s composition (e.g., odor, color, density, melting/boiling point).

What is a chemical property?

A property observed only by changing the substance’s composition (e.g., flammability).

What is energy?

The capacity to do work.

What is work?

The action of a force through a distance.

What is kinetic energy?

Energy associated with motion.

What is potential energy?

Energy associated with position or composition.

What is thermal energy?

Energy associated with temperature due to motion of particles; a type of kinetic energy.

What does the law of conservation of energy state?

Energy is conserved in physical and chemical changes; it is neither created nor destroyed.

What are SI base units?

Meter (m), kilogram (kg), second (s), Kelvin (K), mole (mol), Ampere (A), Candela (cd).

What is the base unit for length?

Meter (m).

What is the base unit for mass?

Kilogram (kg).

What is the base unit for time?

Second (s).

What is the base unit for temperature?

Kelvin (K).

What is the base unit for amount of substance?

Mole (mol).

What is the base unit for electric current?

Ampere (A).

What is the base unit for luminous intensity?

Candela (cd).

How is the meter defined?

The distance light travels in vacuum in 1/299,792,458 seconds.

How many inches are in a meter?

39.37 inches.

What is the kilogram in pounds?

1 kg = 2.205 lb.

How is the second defined?

9,192,631,770 periods of radiation from cesium-133.

What is absolute zero?

0 K; the temperature at which molecular motion virtually stops.

Are Fahrenheit and Celsius degrees the same size?

No. Celsius and Kelvin degrees are the same size; Fahrenheit degrees are not. Conversion: C to K is K = C + 273.15; C to F is F = 1.8C + 32.

What is the relation between Celsius and Kelvin scales?

The degrees are the same size; K = C + 273.15.

How do you convert Celsius to Fahrenheit?

F = 1.8 × C + 32.

What are SI prefixes?

Prefixes that scale units by powers of 10 (e.g., kilo 10^3, mega 10^6, milli 10^-3, micro 10^-6).

What is the symbol for micro?

μ (mu).

What is the derived unit for volume?

Liter (L) or cubic meter (m^3).

What are common density units?

g/cm^3 or g/mL.

What is the density of water at 4 °C?

1.00 g/cm^3.

What is the density of ice at 0 °C?

0.917 g/cm^3.

How do you calculate density?

Density = mass ÷ volume.

What is the density of zinc given 68.60 g and 9.5 cm^3?

≈ 7.22 g/cm^3.

What is the mass of 27.5 cm^3 of gold (density 19.3 g/cm^3)?

≈ 530.75 g (about 531 g).

What is the volume of 225 g of ethanol with density 0.789 g/mL?

≈ 285 mL.

What is an intensive property?

A property independent of the amount of substance (e.g., density).

What is an extensive property?

A property that depends on the amount of substance (e.g., mass).

How is percent by mass expressed?

As a fraction of 100 (percent); can be converted to a conversion factor by using the ratio parts/whole.

What is dimensional analysis?

Using units to solve problems; units are multiplied, divided, and canceled like algebraic quantities.

What is a conversion factor?

A fractional quantity of a unit equation used to convert from one unit to another.

What are unit equations?

Equations of equivalent quantities used to build conversion factors (e.g., 2.54 cm = 1 in).

What is the general problem-solving approach in dimensional analysis?

Identify the starting point and target, devise a plan, solve, and check.

How should you handle units raised to a power in conversion factors?

Raise both the numerical factor and the unit to the same power.

Convert 3.5 m to cm.

350 cm.

Convert 3.5 m^2 to cm^2.

122,500 cm^2.