Lesson 1.06 Flashcards
Matter
Anything that has mass and takes up space
Pure substance
A pure substance consists of a single element or type of compound. For example, gold is a pure substance made from a single element: gold.
Element
An element is a substance that cannot be broken down into simpler substances.
Compound
A compound is matter composed of two or more elements. A molecule is the smallest unit of a compound.
Mixture
A mixture is created when solids, liquids, or gases mix with one another.
Homogeneous mixture
A homogeneous mixture is a mixture that has its different components mixed evenly within the substance.
Heterogeneous mixture
A heterogeneous mixture is a mixture that has its different components mixed unevenly within the substance.
How can a mixture be separated into pure substances?
Mixtures contain compounds and elements that can be physically separated from one another. For example, you can pull out your favorite fruit from a fruit salad and leave the others in the bowl.
How can a compound be separated into individual elements?
Pure substances made from compounds can only be chemically separated into the elements that make them up. The compound table salt (NaCl) is made from the elements sodium and chlorine.
Compare the three types of homogeneous mixtures: colloids, emulsions, and solutions.
Colloids, in which microscopically insoluble particles are suspended throughout another substance, are homogeneous mixtures.
Emulsions are homogeneous mixtures of two or more liquids that are normally not mixable.
Solutions are homogeneous mixtures in which the solute is dissolved and distributed evenly within the solvent.
Define solute and solvent.
Solute: In a solution, the substance that is in a lower quantity; the substance being dissolved
Solvent: in a solution, the substance that is in a greater quantity; the dissolving medium
In a solution, the _______ is in lower quantity and is dissolved in the ______.
In a solution, the SUBSTANCE THAT is in a lower quantity and is the SUBSTANCE BEING dissolved
Compare mixtures and compounds in terms of each of the following:
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Composition
Mixture: Varied composition—there is no set ratio in how the substances mix.
Compound: Definite composition—the atoms are bonded in specific ratios (given in the chemical formula).
Properties
Mixture: Each substance in the mixture retains its own chemical and physical properties.
Compound: The compound has different properties than each of the elements it contains.
Bonding
Mixture: The different substances are not chemically bonded together.
Compound: The different elements are chemically bonded together.
Separation
Mixture: Each substance can be separated from the mixture by physical means.
Compound: The compound can only be separated into its elements by a chemical change (reaction).
Examples
Mixture: Air, most rocks and ores, saltwater
Compound: Water, carbon dioxide, sodium chloride
What physical properties can be used to separate heterogeneous mixtures?
Heterogeneous mixtures can be separated based on physical properties such as size, color, or magnetism.
What physical properties can be used to separate homogeneous mixtures?
Homogeneous mixtures require a little more work to separate their components.
What types of substances can be separated using a magnet?
Much like a metal detector at the beach, you could use a magnet to attract the iron, causing it to move away from the salt molecules.
Describe filtration and the physical properties of the substances that can be separated by this means.
Filtration is a common laboratory technique for separating an insoluble solid from a liquid. In the filtration process, insoluble solids remain behind on the filter paper as the liquid passes through it.
What physical property is used to separate substances in a centrifuge? How is it done?
A centrifuge spins at high speeds until the heavier components (solids or liquids) sink to the bottom and the lighter components (liquids or gases) float to the top. (Centrifugal force)
