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31 Cards in this Set
- Front
- Back
What is a compound?
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A substance formed by the combination of two or more elements in different proportions.
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What is an isotope?
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Atoms of the same element that have different numbers of neutrons.
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What is an element?
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A pure substance that consists entirely of one type of atom.
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What are the 2 main types of chemical bonds?
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Covalent bonds and ionic bonds.
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What is an ionic bond?
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When one or more electrons are transferred between atoms.
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What are ions?
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Positively and negatively charged atoms.
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What is a covalent bond?
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Forms when electrons are shared between atoms.
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What is a molecule?
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The smallest unit of most componds.
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What is a van der Waals force?
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A weak chemical bond that occurs when molecules close together develop slight attractions between oppositely charged regions of nearby molecules.
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Why is a water molecule polar?
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Because there is an uneven distribution of electrons between the oxygen and hydrogen atoms.
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What is cohesion?
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An attraction between molecules of the same substance.
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What is adhesion?
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An attraction between molecules of different substances.
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What is a mixture?
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A material composed of two or more elements of compounds that are physically mixed together but not chemically combined.
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What is a solution?
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A mixture where all the components are evenly distributed throughout the solution.
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What is a solute?
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The substance that is dissolved.
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What is a solvent?
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The substance in which the solute dissolves (usually water).
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What is the greatest solvent on Earth?
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Water.
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What are suspensions?
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Mixtures of water and nondissolved material.
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What is a colloid?
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A mixture where the particles are larger than particles in a solution, but smaller than in a suspension (Ex: jello, cells, yogurt).
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What is the difference between organic and inorganic compounds?
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Organic compounds are made by living things, and Inorganic compounds are not made by living things.
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What are the properties of water?
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It is an excellent solvent, has a high heat capacity, high surface tension, and expands on freezing.
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What is the "secret" of water?
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Water's chemical structure provides the sectret to its effectiveness.
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What is the chemical structure of water?
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The hydrogen and oxygen atoms are on different sides of the molecule; oxygen side is more (-) and the hydrogen side is more (+).
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What are acids?
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Chemicals that release H+ ions in water and increase the concentration of H+ in a solution. (Ex: aspirin, orange and tomato juice)
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What are bases?
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Chemicals that produce hydroxide ions (OH-). (Ex: soap, egg white)
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What is neutralization?
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When an acid and base are mixed, and the hydroxide ion combines with the hydrogen ion to form water.
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Describe the pH scale.
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Acids (lower numbers) to the left, neutral substances in the middle (7), and bases (higher numbers) to the right.
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What does pH stand for?
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Potential hydrogen.
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What does an element's atomic number represent?
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The number of protons it has.
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What does an element's atomic mass represent?
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The number of protons and neutrons in the nucleus.
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What is a buffer?
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A weak acid or base that can react with strong acids or bases to prevent sharp, sudden changes in pH.
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