Study sets, textbooks, questions
Upgrade to remove ads
Chemistry Chapter 5: Water for Life
Terms in this set (65)
A diatomic molecule XY that contains a polar bond must be a polar molecule. However, a triatomic molecule XY2 that contains a polar bond does not necessarily form a polar molecule. Use some examples of real molecules to help explain this difference.
The diatomic molecule (XY) with a polar bond must be polar because the molecule is linear. An example is HCl. The H-Cl bond is polar, and so is the molecule. If the triatomic molecule contains polar bonds, the geometry of the molecule will determine if the molecule is polar or nonpolar. For example, although CO2 has polar C=O double bonds, the molecule is linear and, as a result, nonpolar. The H2O molecule has polar H-O bonds, but is bent. This geometry gives rise to a polar molecule.
Explain why the Lewis structure of water is bent.
The molecule is "bent" because the two lone pairs (nonbonding pairs) of electrons on the oxygen atom occupy space (as do the two bonding pairs of electrons on the O atom). The geometry of the water molecule maximizes the space between all these electron pairs.
Explain the term compound and also why water is not an element.
A compound is a pure substance made up of two or more different elements in a fixed, characteristic chemical combination. Water is a compound because it contains both the elements H and O in a 2:1 ratio, as evidenced by the chemical formula H2O.
Does an NH3 (ammonia) molecule contain polar bonds? Explain.
Each N-H bond is polar. The difference in electronegativity between N and H is 3.0 - 2.1 = 0.9.
Is an NH3 (ammonia) molecule polar?
The ammonia molecule is triangular pyramidal. This shape, together with the polarity of the N-H bonds, causes the molecule to be polar.
Is NH3 (ammonia) soluble in water? Explain.
Ammonia is highly soluble in water. Ammonia and water both are polar molecules, and "like dissolves like."
Is a hydrogen bond an intermolecular or intramolecular force?
A hydrogen bond is an intermolecular force, which is a force between water molecules and not within each water molecule.
What correlations can be drawn about the difference in electronegativity between bonded atoms and their tendency to form ionic or covalent bonds?
Larger differences in electronegativity are associated with ionic bonds; smaller differences with covalent bonds.
An aqueous solution of KCl conducts electricity, but a solution of sucrose does not. Explain.
The solution of the ionic compound KCl contains K+(aq) and Cl-(aq). In contrast, sucrose is a covalent compound that forms no ions in solution. Ions need to be present to conduct electricity.
What does water do when it freezes?
water is a _ at room temperature
liquid (25 degrees C)
water has a high boiling point of
100 degrees C
a measure of the attraction of an atom for an electron in a chemical bond
polar covalent bond
a covalent bond in which the electrons are not equally shared but rather are closer to the more electronegative atom
a force that exists within a molecule
a force that occurs between molecules
an electrostatic attraction between a H atom bonded to a highly electronegative atom (O, N, or F) and a neighboring O, N, or F atom, either in another molecule or in a different part of the same molecule
the mass per unit volume
the quantity of heat energy that must be absorbed to increase the temperature of 1 gram of a substance by 1 degree C
water that is safe to drink and to cook with
an estimate (for an individual or a nation) of the amount of water required to sustain the consumption of goods and services
the fresh water found in lakes, rivers, and streams
fresh water found in underground reservoirs also known as aquifers
only _ is fresh water
a substance, often a liquid, that is capable of dissolving one or more pure substances
the solid, liquid, or gas that dissolves in a solvent
solutions in which water is the solvent
a unit of concentration represented by the number of moles of solute present in 1 liter of solution
a type of glassware that contains a precise amount of solution when filled to the mark on its neck
an apparatus that produces a signal to indicate that electricity is being conducted
a solute that is nonconducting in aqueous solutions, dissolve in h20 but don't associate into ions
a solute that conducts electricity in aqueous solution
an atom or group of atoms that has acquired a net electric charge as a result of gaining or losing one or more electrons
a positively charged ion
a negatively charged ion
the chemical bond formed when oppositely charged ions attract
composed of ions that are present in fixed proportions and arranged in a regular, geometric structure
two or more atoms covalently bound together that have an overall positive or negative charge
compounds that help polar and nonpolar compounds to mi x, sometimes called "wetting agents"
the increase in concentration of certain persistent chemicals in successively higher levels of a food chain
maximum contaminant level goal (MCLG)
the maximum level of a contaminant in drinking water at which no known or anticipated adverse effect on human health would occur
maximum contaminant level (MCL)
the legal limit for the concentration of a contaminant expressed in parts per million or parts per billion
the chlorine containing chemicals that remain in the water after the chlorination step. These include hypochlorous acid, the hypochlorite ion, and dissolved elemental chlorine
compounds such as CHCl3 (chloroform), CHBr3 (bromoform), CHBrCl2 (bromodichloromethane), and CHBr2Cl (dibromochloromethane) that form from the reaction of chlorine or bromine with organic matter in drinking water
biological oxygen demand (BOD)
a measure of the amount of dissolved oxygen microorganisms use up as they decompose organic wastes found in water
any process that removes ions from salt water
a separation process in which a liquid solution is heated and the vapors are condensed and collected
the passage of water through a semipermeable membrane from a solution that is less concentrated to a solution that is more concentrated
uses pressure to force the movement of water through a semipermeable membrane from a solution that is more concentrated to a solution that is less concentrated
A cube of solid ethanol sinks rather than floats in liquid ethanol. Explain this behavior.
The cube sinks because the density of the solid phase is greater than the density of the liquid phase. Ethanol molecules are closer together than water molecules are in ice.
What percentage of Earth's water is in the oceans?
fully dissolve (soluble)
doesn't fully dissolve (insoluble)
sugar is a _ molecule and dissolves in water
oil is a _ molecule and is insoluble in water
Pure covalent EN:
Polar covalent EN:
Greater than 1.4 but less than 1.8
Greater than 1.8
Which element has the most electronegativity?
When naming formulas, is it important to name the prefixes?
On compounds where both elements
are non metals, the use of prefixes is a must.
dissolve in h20 but don't associate into ions
do not fully dissolve (insoluble)
fully dissolve (soluble)
Sets found in the same folder
Chemistry Chapter 7
Chapter 4 Practice
Chemistry Chapter 6
AP Chem Cations/Anions
Sets with similar terms
Mastering Biology 2 Water
CHE 100 - Chapter 5: Water for Life
bio unit 7 assesment
Other sets by this creator
Chem Final Exam
Bio Final Exam
Chem Ch. 8
Chemistry Ch 7: Nuclear Fission
Other Quizlet sets
AP Bio Exam (Study Guide Edition)
Chem Unit One
Study Guide for Chemistry Final Exam