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Conceptual Chemistry Mid-term Review Outline

Use this outline in conjunction with website listing all assignments, labs, and quizzes at http://bawhalen.tripod.com

 

Introduction to Chemistry in the World Around Us

1.      Explain the movie “A Civil Action”

A.     “A Civil Action” was the true story of contamination of groundwater due to illegal dumping of solvents, and the subsequent health impact on the citizens of Woburn, MA.

(1)   Contamination of groundwater lead to contamination of drinking water.

(2)   A cancer cluster developed in Woburn.

2.      Describe / explain the Scientific Method as the process of acquiring knowledge of the physical universe through observation, measurement and inference

A.     Physical properties (color, smell, hardness, etc.) are qualitative observations

B.     Measurement is quantitative – the best type of information

C.     The Steps of the Scientific Method

a)      Identify a problem, Hypothesizing – make an educated guess, Test, Gather Data, Come to a Conclusion, Publish

 

Unit One

1.      Measurement and the Metric System

A.     Name and write the abbreviation of the SI unit for length, mass, time, temperature and derived units volume and density.

a)      Base units – gram, meter, liter

B.     Demonstrate that you know the metric prefixes and can convert one metric unit into another.

a)      K – h – D – base unit – d – c – m

C.     Calculate density by using the formula D=M/V.

2.      Water Uses

a)      Discuss direct and indirect water uses and their importance.

B.     Back through the Water Pipes

a)      Identify techniques of water purification

C.     Where is the Earth’s Water?

a)      Describe the function of and operation of the hydrologic cycle and indicate the primary storage reservoirs of the Earth’s water supply.

(1)   Water Cycle  The movement of water between the Earth and its atmosphere.  Water is evaporated (from bodies of water, soil, plants and animals) by heat of the Sun.  Water vapor cools in the atmosphere, condenses, and falls to Earth as precipitation (rain, sleet, snow).  Most of the water that falls to Earth as precipitation falls on the oceans.  Water that falls on land can runoff and collect in streams and rivers, or becomes groundwater.

(2)   Earth’s Water  Most of the Earth’s water is in the oceans.  Fresh water accounts for only 2.8% of the total water, and of that most is found in the glaciers and ice caps.

3.      A Look at Water and its Contaminants

A.     Physical Properties of Water

a)      Water exists in 3 states, solid as ice, liquid as water, and gas as water vapor.

b)      Density of water is 1 g/mL. 

c)      Density (D) = Mass (M) / Volume (V)

(1)   Ice is less dense then water.

(2)   If something is more dense than water (>1g/mL) then it will sink in water.  If less dense than water, then it will float.  Oil floats on water!

 

B.     Mixtures and Solutions

a)      Define the terms solution, solvent and solute and apply them in examples.

b)      Classify matter in terms of elements, compounds, and mixtures; and distinguish among different types of mixtures (homogeneous = solutions, and colloids and suspensions = heterogeneous).  Suspensions eventually settle out, colloids are so fine they do not.

c)      Tyndall effect – the scattering of light by suspensions or colloids

C.     Symbols, Formulas and Equations

a)      Interpret the symbols and formulas in balanced chemical equation in terms of atoms and molecules.

(1)   Know the names of the common elements (handout), and identify their chemical symbols.

(2)   Understand following terms

(a)    Chemical symbols – represent elements

(b)   superscript –used to show the charges on ions

(c)    subscript – used to show the numbers of atoms in a formula unit

(d)   coefficients – used to show the number of molecules

(e)    chemical formula – represent compounds

(f)     chemical equation – represent reactions

(g)    reactants

(h)    products

(i)      atoms – smallest particle of an element

(j)     molecule – smallest particle of a compound

(k)   diatomic molecules – there are seven, (like O2) – who always exist as molecules of 2 atoms (remember:  GEN – U – I NE  = elements which end “gen” and “ine” are the diatomic ones)

(l)      Conservation of Matter

D.     The Electrical Nature of Matter

a)      Describe the 3 basic subatomic particles (proton, neutron and electron) and their connection to the polarity and solubility of a compound.

(1)   Protons – p+, has a positive charge, part of nucleus

(2)   Neutron - n°, has no charge, part of nucleus

(3)   Electron – e-, has negative charge, circling outside nucleus

b)      Remember:  opposites attract.

c)      Atomic number = # protons

d)      Atomic mass = sum of # protons and neutrons

e)      In an element, the # protons  = # electrons, because overall it is neutral

E.      Periodic Table

a)      Period – is the horizontal row

b)      Group or Family is the vertical column

c)      The valence electrons are the outermost electrons – farthest from the nucleus

d)      The columns of the periodic table are labeled I, II, III, IV, V, VI, VII and VIII (ignoring the transition and rare earth elements).  This label tells you the number of valence electrons of every element in that column (except He).

e)      All valence electrons want to achieve nirvana – 8 electrons in the outer shell – this is the Octet Rule.

F.      Ions

a)      Cation – positive ion – formed by LOSING one or more electrons

b)      Anion – negative ion – formed by GAINING one or more electrons

c)      Ionic compound – made of a positive and a negative ion but resulting compound is neutral

(1)   Metals become positive ions, non-metals become negative ions

(2)   Formula is written cation first – then anion

(3)   Given the formula of an ionic compound, you can determine the original ions and their charge

(4)   Write formulas for ionic compounds if given the ions.

d)      Water is a polar molecule.  The molecule looks like a pair of Mickey Mouse ears. 

G.     Solubility

a)      Define terms saturated, unsaturated, and supersaturated solutions and apply them to examples.

b)      Solubility of a salt increases with increasing temperature.

c)      Solubility of a gas decreases with increasing temperature.

d)      Solubility is represented by a solubility curve.  Interpret and analyze solubility curves.

e)      Ions dissolve well in polar solvents such as water.  “Like dissolves like”.  Water is known as the universal solvent.

H.     Acids, Bases and pH Scale

a)      The pH scale is a measure of hydrogen ion concentration.  Ranges from a low of 0 to a high of 14.  With pH 7 as neutral.  Less than pH 7 is acidic; greater than pH 7 is basic.

b)      Identify household acids and bases.

c)      Identify pH indicators.

I.        Water Purification and Treatment

a)      Hardwater and water softeners – hard water is due to the presence of Ca, Mg or Fe ions.  Softening removes these ions and replaces them with Na ions.

b)      Treatment of sewage – awareness of the steps

c)      Treatment of drinking water – chlorination is for disinfection and fluoridation is dental protection

4.      Changes of Matter

A.     Physical and Chemical Properties

a)      Physical properties can be measured from a sample of the substance alone (density, melting point, boiling point, color, etc.)

b)      Chemical properties are measured when a sample is mixed with another chemical (reaction with acid, flammability)

B.     Physical and Chemical Changes

a)      Physical changes imply that no new substances are being formed (melting, boiling, dissolving, etc.)

b)      Chemical Changes imply that the substances are forming a new substance, or decomposing into a new substance.  This change is indicated by heat, light, gas formation, color changes, etc.