Chemistry Mid-Term Review
Chapter One:
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What is chemistry? Chemistry is the study of the transformation of matter, the
study of reactions between matter
Define hypothesis, experiment, and conclusion
o Hypothesis – a prediction of the relationship between variables based on
previous observations (“an educated guess”)
o experiment – a detailed procedure in order to test hypothesis
o conclusion – a summary of the findings and results based on the
experiment, identifies if hypothesis was supported or not in experiment
Describe the scientific method.
o Questions/problem – identify a question based on an observation
o Hypothesis – a prediction of the relationship between variables
o Experiment – a designed procedure to test hypothesis
o Data – collect data from experiment
o Analyze results – analyze relationship between tested variables
o Conclusion – summary of findings
Chapter 2
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What three states can matter exist in? Describe each of the three properties.
o Solid – fixed volume, shape
o Liquid – fixed volume, variable shape (dependent upon container)
o Gas – variable volume, shape (dependent upon container)
What is the difference between a physical change and chemical change?
o Physical change – phase change, change in appearance
o Chemical change – matter changing into totally new product with new
physical, chemical properties
What is the difference between a heterogeneous and homogeneous mixture?
o Heterogeneous – mixture of two or more components in which you can
see the different components
o Homogeneous – mixture of two or more components in which there is a
uniform appearance
What are the characteristics of a pure substance?
o Pure substance has a uniform appearance, same physical properties
throughout (boiling pt, melting pt, density, etc.)
What are the two types of pure substances?
o Element (gold, carbon like a diamond, silver), compound (table salt,
sugar, pure water)
Elements are composed of? Atoms
Compounds are composed of different types of _elements_ and many compounds
contain ________ions________________.
Define molecules. Molecules contain two or more atoms combined
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Give three examples of heterogeneous mixtures and three examples of solutions
that you may use in everyday life.
o Heterogeneous – salt/pepper, dirt, oil/vinegar
o Homogeneous – saltwater, Koolaid, air
List three events that would be classified as a chemical change and three events
that are classified as a physical change.
o Chemical change – cooking an egg, burning a marshmallow, baking soda
and vinegar
o Physical change – breaking glass, painting a fingernail, ripping a paper
Chapter 3
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What are the three main parts of an atom? Proton, neutron (nucleus), electron
Define an ion. Charged atom (cation – positively charged atom, anion –
negatively charged atom)
Define an isotope. Atoms that have the same number of protons, but different
number of neutrons
Identify the elements that are not represented by the first letter in their names
on the periodic table.
o Answers can include sodium (Na), potassium (K), gold (Au), silver (Ag)
What is a compound? A combination of two more or different atoms that exist as
ions
Write the formula for each of the following substances, list the elements in the
given order.
o A molecule containing one phosphorous atom and three chlorine atoms.
PCl3
o A compound containing one carbon atom and four bromine atoms. CBr4
Write the following in A/Z/X notation
o Z = 8, neutrons 9 178O
o Number of protons = 26, number neutrons = 31 5726Fe
o Z = 3, number of neutrons 4 73Li
Why are the elements of Group 8 referred to as the noble gasses? Noble,
referring to being non-reactive with other elements
Chapter 4
 What is a binary compound? Two elements combined in a compound
 Name the simple binary compounds
o NaI sodium iodide
o SrO strontium oxide
o CsI cesium iodide
 Write the name of each of the following ionic substances, using Roman Numerals
to indicate the charge of the cation.
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o CoCl2 cobalt (II) chloride
o PbO lead (II) oxide
o Fe2O3 iron (III) oxide
Write the name for each of the following binary compounds of nonmetallic
elements (type 3).
o NI3 nitrogen triiodide
o SeO selenium monoxide
o NH3 nitrogen trihydride, ammonia
Give the name of each of the following polyatomic anions.
o NO3-1 nitrate
o ClO-1 hypochlorite
o NH41+ ammonium
o PO43- phosphate
Write the formulas for the simple binary ionic compounds.
o lithium oxide Li2O
o silver oxide Ag2O
o sodium sulfide Na2S
HONORS ONLY: Memorize the polyatomic ions
Chapter 5
 Write the following as a decimal.
o 6.235 x 10^-2 0.06235
o 8.621 x 10^4 86210
o 7.229 x 10^3 7229
 Write the following in scientific notation
o 0.000067 6.7 x 10^5
o 9,331,442 9.331442 x 10^6
 Which distance is further 100m or 100km? 100 km
 52.2mm is equal to how many cm? 5.22cm
 Identify the number of sig figs by drawing an underline below the sig figs.
o 1422 - 4
o 65,321 - 5
o 200 - 1
o 0.0303 - 3
 What is the different between rounding when you add or subtract, compared to
when you multiply and divide?
o Adding/subtracting – round to the lowest number of decimal places
o Multiplying/dividing – round to the lowest number of significant
numbers
Chapters 7 and 8 (reactions)
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Balance the following equations
o SiI4 + 4Mg -> 4Si + 4MgI
o K2CO3 -> K2O + CO2 already balanced
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What are the major reaction types that we discussed? If we discussed a generic
equation, make sure you include it.
o Synthesis – A + B  AB
o Decomposition – AB  A + B
o Single replacement – A + BC  AB + C OR A + BC  AC  B
o Double displacement – AB + CD  AD + CB
o Combustion – CnHn+2 + O2 CO2 + H2O
What are phase symbols and how are they used?
o solid – s, liquid (l) , gas (g), aqueous solution (aq)
What is the difference between a subscript and a coefficient? subscript identifies
number of atoms, coefficient is the number of molecules
How do you determine if a substance is soluble in water or not? use solubility
rules
What is the difference between word, skeleton, complete molecular, complete
ionic, and net ionic equations?
o word – names of compounds, elements involved in reaction
o skeleton – chemical formulas of compounds involved in reaction
o complete molecular – chemical formulas, with phase symbols and
balanced
o complete ionic – shows dissociation of compounds dissolved in water
o net ionic – shows only ions involved in formation of precipitate
o What are spectator ions? Ions that are not involved in formation of
precipitate, “watching” ions
o Write all of the above for K2CO3 -> K2O + CO2
o see board
What is the net ionic equation for the reaction of a strong acid with a strong
base? H+(aq) + OH-(aq)  H2O(l)
HONORS ONLY: Memorize the solubility rules
Chapter 3 and 11 (atomic theories)
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Draw pictures of the following models of the atom. Label subatomic particles in
each.
o Dalton sphere, no subatomic particles
o Thomson positively charged sphere with electrons randomly dispersed
o Rutherford – sphere with nucleus at center containing protons, and
electrons randomly dispersed
o Bohr – solar system model, electrons orbiting nucleus contacting protons
and neutrons
Describe what Rutherford’s gold foil experiment was and what he discovered.
Positively charged alpha particles shot at piece of gold foil. Particles that were
reflected at different angles signified that at the center of the atom contained a
dense, positively charged mass. This identified the location of protons in nucleus.
Draw Electron Box Diagrams for each of the following
o Mg   
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o F   
o Ar   
Write shortcut notation of Electron Diagrams for each of the following
o O [He] 2s22p4
o Cu [Ar] 4s23d9
o Pb [Xe] 6s24f145d106s2
Laboratory Equipment and Safety
 List four safety terms and their definitions. Examples can include:
o Flammable – ignites in presence of heat or flame
o Carcinogen – cancer causing agent
o Toxic – can be fatal or cause serious injury
o Mutagen – causes mutations of genetic material
 Explain what the following types of glassware are best used to do.
o Beaker – hold/ heat liquids
o Flask – measure liquids, hold/heat liquids
o Glass rod –stir liquids
o Watch glass – evaporation of liquid
 Pick three kinds of personal protective equipment we might use in the
laboratory and explain why we would use them.
o goggles – protect eyes
o aprons – protect clothes
o gloves – protect hands