Matter Test 2 - Chem

What is matter?

Anything that has mass and takes up space (volume).

What are the main characteristics of matter?

Mass, volume, energy, gravity, and inertia.

What is mass?

The amount of matter in an object, measured in grams or kilograms.

What is volume?

The amount of space an object takes up, measured in liters or other volume units.

What is inertia?

Resistance to a change in motion.

What are the two categories of matter?

Substances and mixtures.

What is a substance?

Matter with a definite composition and uniform properties.

What are the characteristics of substances?

They have a definite composition, a chemical formula, uniform properties, and cannot be physically separated.

What are the two types of substances?

Elements and compounds.

What is a mixture?

A combination of two or more substances that are physically combined.

What are the characteristics of mixtures?

They have varying composition, no chemical formula, more than one set of properties, and can be physically separated.

What is a homogeneous mixture?

A mixture that has a uniform composition throughout.

What is another name for a homogeneous mixture?

A solution.

What are examples of homogeneous mixtures?

Aqueous solutions (substances dissolved in water) and substances dissolved in alcohol.

What is a heterogeneous mixture?

A mixture in which you can see different phases or parts.

What are ways to separate mixtures?

Distillation, filtration, centrifuging, sieving, solubility, electrophoresis, and chromatography.

What is distillation?

A separation method that uses differences in boiling points.

What is filtration?

A method that separates solids from liquids using a filter.

What is centrifuging?

A separation method that uses density and spinning.

What is chromatography?

A method of separating substances based on how they move through a material.

What is an element?

A substance made of only one type of atom.

Can an element be broken down by chemical means?

No. An element cannot be broken down into simpler substances by chemical means.

What are the four types of elements?

Metals, nonmetals, semimetals (metalloids), and noble gases.

What are metals generally like?

Most are solids and are located on the left side of the periodic table, except hydrogen.

Where are nonmetals located on the periodic table?

Mostly to the right of the staircase, excluding group 18.

Where are semimetals located?

Along the staircase on the periodic table, including germanium and antimony.

Where are noble gases located?

Group 18 of the periodic table.

What is a compound?

A chemical combination of two or more elements, such as H2O.

Can compounds be decomposed?

Yes, compounds can be broken down chemically into simpler substances.

What are the two main types of compounds?

Inorganic compounds and organic compounds.

What are inorganic compounds?

Compounds without carbon, except carbonates.

What are organic compounds?

Compounds containing carbon, except carbonates.

What is a binary compound?

A compound containing only two different elements.

What is a ternary compound?

A compound containing three different elements.

How can you recognize an acid from its formula?

Its formula usually starts with H or ends in -COOH.

How can you recognize a base from its formula?

Inorganic bases usually end in -OH; organic bases contain NH.

What is a salt?

A compound containing a metal and a nonmetal other than OH.

What is a physical property?

A property that can be determined without changing the chemical formula or identity of a substance.

What is a chemical property?

A property that describes how a substance behaves or reacts with other substances.

What is a physical change?

A change that does not change the chemical identity of a substance.

What are examples of physical changes?

Phase changes, dissolving, and changes in size.

What is a chemical change?

A change that creates a new substance through a chemical reaction.

What are examples of chemical changes?

Burning and reacting with acids or bases.

What is formula mass?

The sum of the masses of all the atoms in a compound, measured in amu.

How do you calculate formula mass?

Add the atomic masses of every atom in the chemical formula.

What is the formula mass of CO2?

C = 1 × 12.0 = 12.0 amu; O = 2 × 16.0 = 32.0 amu; total = 44.0 amu.

What is gram formula mass?

The mass of one mole of a substance, measured in grams.

What is the gram formula mass of CO2?

44.0 grams per mole.

What is percent composition by mass?

The percentage of the total mass that comes from a particular element in a compound.

What is the formula for percent composition?

% composition = (mass of part ÷ total mass) × 100.

What are the three phases of matter?

Solid, liquid, and gas.

What are the characteristics of a solid?

Definite shape and volume, closely packed particles, and a definite structure.

What is a crystalline solid?

A solid whose particles form an organized, regular geometric pattern.

What is an amorphous solid?

A solid whose particles do not have a regular geometric pattern.

What is the potential energy of particles in a solid compared with liquids and gases?

Solids generally have the lowest potential energy.

What type of motion do particles in a solid have?

Mostly vibrational motion.

What are the characteristics of a liquid?

Definite volume but no definite shape; it takes the shape of its container.

How are liquid particles arranged?

They are close together, more like solid particles than gas particles.

What types of motion do liquid particles have?

Vibrational, rotational, and limited translational motion.

What is a fluid?

A substance that can flow, such as a liquid or gas.

What are the characteristics of a gas?

No definite shape or volume; it fills its container.

How do gas particles move?

They move quickly and are far apart.

How does gas particle spacing compare with solids and liquids?

Gas particles are much farther apart.

What is the density of a gas compared with solids and liquids?

Gases generally have the lowest density.

What is the potential energy of gas particles compared with solids and liquids?

Gases generally have the highest potential energy.

What are the intermolecular attractions in gases like?

Very weak.

How do temperature and pressure affect gas volume?

Changes in temperature and pressure can change gas volume.

What is a phase change diagram?

A graph showing temperature versus time as a substance is heated or cooled.

What do plateaus on a phase change diagram represent?

Phase changes.

What do diagonal sections on a phase change diagram represent?

Changes in kinetic energy as temperature changes.

What do horizontal sections on a phase change diagram represent?

Phase changes, when temperature stays constant.

What are heating and cooling curves?

Graphs showing how a substance's temperature changes as it is heated or cooled.

What is a phase diagram?

A graph showing pressure versus temperature for a substance.

What do the lines on a phase diagram represent?

Boundaries separating the three phases of matter.

What happens along the lines of a phase diagram?

Two phases exist together in equilibrium.

What is the triple point?

The temperature and pressure at which all three phases exist in equilibrium.

What is the critical temperature?

The highest temperature at which a liquid can exist.

What is the critical pressure?

The pressure of a gas at its critical temperature.

What is vapor pressure?

The pressure created by vapor above a liquid when evaporation and condensation are in equilibrium.

How does temperature affect vapor pressure?

As temperature increases, vapor pressure increases.

Why does vapor pressure increase when temperature increases?

More liquid particles have enough energy to escape into the gas phase.

What is boiling point?

The temperature at which a liquid's vapor pressure equals the surrounding atmospheric pressure.

What happens when a liquid's vapor pressure equals atmospheric pressure?

The liquid boils.

How does increasing atmospheric pressure affect boiling point?

Increased atmospheric pressure increases the boiling point.

What does a low boiling point indicate?

The substance is easier to separate into vapor because its intermolecular attractions are relatively weak.

What is the conversion between calories and joules?

1 calorie = 4.18 joules.

What is kinetic energy?

The energy of motion.

What is thermal energy?

The internal energy associated with the motion and interactions of particles in a substance.

What is heat?

The transfer of thermal energy from a warmer object to a cooler object.

What is potential energy?

Stored energy based on position or interactions.

What is needed for potential energy between particles?

At least two particles interacting through attractive or repulsive forces.

How does increasing the distance between interacting particles affect attractive forces?

The attractive force generally weakens as distance increases.

What is an endothermic process?

A process that absorbs energy from its surroundings.

How does an endothermic process feel?

Cold to the surroundings.

What is the sign of enthalpy change (ΔH) for an endothermic process?

Positive (+ΔH).

What is an exothermic process?

A process that releases energy to its surroundings.

How does an exothermic process feel?

Hot or warm to the surroundings.

What is the sign of enthalpy change (ΔH) for an exothermic process?

Negative (-ΔH).

What is the formula for calculating heat transfer when temperature changes?

q = mcΔT.

What is the formula for calculating heat during a phase change?

q = mH, using heat of fusion (Hf) or heat of vaporization (Hv), depending on the phase change.