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61 Cards in this Set
- Front
- Back
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Polar Molecule
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a molecule in which the charges are unevenly distributed
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Why is a water molecule polar?
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the oxygen atom has 8 protons which attracts more electrons than the hydrogen atom which has a single proton.
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Explain a hydrogen bond between water molecules.
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The hydrogen atom of one water molecule is attracted to the oxygen atom of another water molecule.
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Cohesion
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an attraction between molecules of the same substance.
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How can a spider walk on water?
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the attraction between water molecules (cohesion) causes "surface tension".
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What is the basic unit of matter?
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atom
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What subatomic particles make up atoms?
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protons, neutron and electrons
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Do neutrons carry a charge?
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No -- they are neutral particles
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What charge is an electron?
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negative
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What charge is a proton?
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positive
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What is an element?
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a pure substance made up of one type of atom
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What is an element's atomic number
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the number of protons in an atom of the element.
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Atoms of the same element that differ in the number of neutrons they contain are called ________.
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isotopes
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The sum of the protons and neutrons in the nucleus of an atom is called____________.
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mass number
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What is a compound?
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a substance formed by the chemical combination of two or more elements in definite proportions.
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The composition of compounds is shown by a shorthand known as a ______________.
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Chemical Formula
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What are chemical bonds?
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They hold atoms in compounds together.
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Name the 2 main types of chemical bonds.
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Ionic and Covalent
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How is an ionic bond formed?
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When one or more electrons are transferred from one atom to another.
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What is an ion?
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Positively or negatively charged atoms.
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How does a covalent bond form?
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when electrons are shared between atoms.
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What structure results when atoms are joined together by covalent bonds?
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a molecule
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What is a molecule?
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the smallest unit of most compounds
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What is Van der Waals Forces?
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Slight attraction between oppositely charged regions of nearby molecules.
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What is adhesion?
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An attraction between molecules of different substances. Example -- causes capillary action
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What is a mixture?
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a material composed of 2 or more elements or 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 components are evenly distributed.
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What is a solute?
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the substance that is dissolved in a solution
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What is a solvent?
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the substance in which the solute dissolves.
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What is the greatest solvent on Earth?
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water
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What is a suspension?
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a mixture of water and nondissolved material
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What is the pH of pure water?
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7
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Solutions with a pH below 7 are called _______
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Acidic
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Solutions with a pH above 7 are called __________
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basic
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The lower the pH of a solution means that _____
The higher the pH of a solution means that _____ |
it is more acidic and had more hydrogen ions.
it is more basic and has fewer hydrogen ions. |
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What is an acid?
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Any compound that forms hydrogen ions (H+) in solution.
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What is a base?
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a compound that produces hydroxide (OH-) ions in solution.
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What is a buffer?
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weak acids or bases that can react with strong acids or bases to prevent sharp sudden changes in pH.
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What is the most versatile element?
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carbon
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What are macromolecules?
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Giant molecules that are made from thousands or hundred thousands of smaller molecules
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What are monomers?
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Smaller units of compounds
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Name 4 groups of organic compounds/macromolecules
found in living things: |
carbohydrates, lipids, nucleic acids, proteins
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What are carbohydrates?
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Compounds made up of carbon, hydrogen, and oxygen atoms. Used by living things are their main source of energy.
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What are lipids?
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Made mostly from carbon and hydrogen atoms. Used to store energy. Common lipid categories: fats, oils and waxes
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What are nucleic acids?
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Macromolecules containing hydrogen, oxygen, nitrogen, carbon and phosphorus. Store and transmit hereditary or genetic information. RNA and DNA
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What are proteins?
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Macromolecules that contain nitrogen and carbon, hydrogen and oxygen. Some proteins control rate of reactions of cell processes. Some form bone and muscle. Some transport substances our of cells or help fight disease.
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What monomers make up proteins?
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amino acids
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What is a chemical reaction?
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a process that changes one set of chemicals into another set of chemicals.
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What are reactants?
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the elements or compounds that enter into a chemical reaction
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What are products?
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the elements or compounds produced by a chemical reaction
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What happens to energy during chemical reactions?
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Energy is either released or absorbed.
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What is the energy needed to get a reaction started called?
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activation energy
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What is a catalyst?
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a substance that speeds up the rate of a chemical reaction
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What are Enzymes?
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proteins that act as biological catalysts. They speed up chemical reactions that take place in cells.
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Give an example of a carbohydrate
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glucose
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What is a monomer of a carbohydrate?
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simple sugars
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What is an example of a lipid?
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membranes
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What is polymerization?
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a chemical process that combines monomers to form a polymer
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Describe 3 factors that influence enzyme activity.
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pH, temperature, proteins
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LIst 3 organs in the human body that produce enzymes.
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pancreas, liver, duodenum
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What is the function of enzymes produced by organs in the digestive system?
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break down food
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