Unit 2 Cheistry

Density

Density

The mass of a substance per unit volume.

D=m/V

The formula to calculate density, where D represents density, m represents mass, and V represents volume.

Freezing

The process of a substance changing from a liquid to a solid state due to a decrease in temperature.

Ice

Solid water.

Precision

The degree of exactness or accuracy in measurement.

Measure

To determine the size, length, or quantity of something using a specific unit of measurement.

Precision

The degree of exactness or accuracy in measurement.

Graduation

A mark or line on a measuring instrument indicating a specific measurement.

Estimate

An approximate calculation or judgment.

Measurement

The process of determining the size, length, or quantity of something using a specific unit of measurement.

Density of water

The mass of water per unit volume, which is 1 gram per milliliter (g/mL).

Pure substances

Substances that are not mixed or contaminated with other substances.

Buoyant

The ability to float or rise in a liquid or fluid.

Sink

To move downward or descend in a liquid or fluid.

Float

To rest or remain on the surface of a liquid or fluid.

Kilogram

A unit of mass in the metric system, equal to 1000 grams.

Mass

The amount of matter in an object.

Substances

Materials or matter with specific properties and characteristics.

CRC Handbook

A reference book that provides data and information on various topics, including the density of pure substances.

Persons

Individuals or people.

Density Tables

Tables or charts that provide information on the density of different substances.

Identify

To recognize or determine the nature or characteristics of something.

Aluminum

A metallic element with the symbol Al and atomic number 13, with a density of 2.70 g/mL.

Copper

A metallic element with the symbol Cu and atomic number 29, which is more dense than Cadmium.

Cadmium

A metallic element with the symbol Cd and atomic number 48.

Solids

A state of matter characterized by a fixed shape and volume.

Water

A transparent, odorless, and tasteless liquid compound consisting of hydrogen and oxygen.

Order

To arrange or rank items in a specific sequence or pattern.

Iron

A metallic element with the symbol Fe and atomic number 26.

Brass

A metallic alloy made of copper and zinc.

Granite

A type of igneous rock composed of minerals such as quartz, feldspar, and mica.

Silver

A metallic element with the symbol Ag and atomic number 47.

Matter

Anything that has mass and takes up space.

Separation Methods

Techniques used to separate different substances in a mixture.

Element

A pure substance made up of only one type of atom.

Pure Substances

Substances that are made up of only one type of particle and cannot be broken down by chemical change.

Compounds

Substances made up of two or more elements held together by a chemical bond.

Mixtures

A combination of two or more substances that are not chemically combined.

Homogeneous Mixture

A mixture that has the same composition throughout.

Heterogeneous Mixture

A mixture that has different visible parts.

Separation by physical means

Methods of separating mixtures using physical techniques such as sorting, filtration, evaporation, distillation, magnetism, chromatography, crystallization, and floatation.

Separation by chemical means

Methods of separating compounds using chemical reactions such as heat or electric current.

Homogeneous Mixtures

Mixtures that have the same composition throughout.

Alloy

A homogeneous mixture of two or more metals.

Solutions

Homogeneous mixtures where one substance dissolves in another.

Suspensions

Heterogeneous mixtures where particles settle to the bottom over time.

Homogeneous mixture

A mixture where the particles are evenly distributed and cannot be filtered.

Solute

The substance that is mixed into a solution.

Solvent

The substance that does the dissolving in a solution.

Solution

A homogeneous mixture of solute and solvent.

Aqueous solutions

Solutions where water is the solvent.

Universal solvent

Water, which has the ability to dissolve many substances.

Evaporation

A separation method that separates solids from liquids by evaporating the liquid.

Decantation

A separation method that separates liquids of differing density by pouring off a layer.

Filtration

A separation method that separates substances with particles of different sizes by filtering.

Magnetism

A separation method that separates solids that contain iron, nickel, or cobalt using a magnet.

Coagulation or flocculation

A step in community water treatment that uses chemical properties to remove dirt or unwanted material from water.

Sedimentation

A step in community water treatment that involves the removal of unwanted material.

Pure Substances

Materials that are free of impurities and contaminants, have the same chemical composition, and well-defined physical properties.

Physical Properties

Characteristics observed without the production of a new substance, such as appearance, density, state, phase change, ductility, malleability, conductivity, solubility, and magnetism.

Density

The mass of a substance per unit volume.

Solubility

The maximum amount of solute that can dissolve in a standard amount of solvent.

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Solid

A state of matter with a defined shape and volume; particles are closely packed.

Liquid

A state of matter with a defined volume; particles are close together but can slide or move against each other.

Gas

A state of matter with no defined shape or volume; particles are in motion and can expand and compress easily.

Plasma

A state of matter similar to gases but exists at high temperatures and has a different set of properties.

Crystalline structure

A patterned arrangement of atoms and molecules found in solid substances.

Surface tension

The attraction between atoms and molecules in a liquid that creates a strong surface layer.

Viscosity

The thickness or resistance to flow of a liquid.

Volatile

Substances that easily turn into gas at room temperature.

Melting

The phase change from solid to liquid.

Freezing

The phase change from liquid to solid.

Condensation

The phase change from gas to liquid.

Vaporization (Evaporation)

The phase change from liquid to gas.

Sublimation

The phase change from solid to gas.

Deposition

The phase change from gas to solid.

Temperature

The average kinetic energy of particle motion; measures hotness or coldness.

Heat

Thermal energy that flows from hot to cold materials.

Phase change

A transition between different states of matter.

Heating curve

A graph that shows how temperature changes during a phase change.