Download Key To T2 Review For Final Study Guide File - District 196 e

Key To T2 Final Review 2015
1. Determine the number of significant figures in the following numbers:
a. .00356 g
c. .5000 L
b. 1.00 m
d. 50 s
2. Write each measurement in scientific notation or in standard form. Record each
measurement to 3 significant figures.
a. 39980 kg
4.00 x 104 kg
-3
b. 7.45583 x 10 mol
.00746 mol
3. Using dimensional analysis, convert the following:
a. 6.00 g to kg
6.00 x 10-3 kg
3
b. 1.86 x 10 mg to g
1.86 x 106 g
c. 46 cm3 to quarts
.049 qt
4. Define the law of conservation of mass and explain how this law is implemented
when balancing equations.
Mass cannot be created or destroyed in ordinary chemical reactions. This law is
applied to balancing when coefficients are placed in front of elements or compounds
to make the number of atoms on both sides of the equation equal.
5. Name the following compounds:
a. P4O8 tetraphosphorous octaoxide
b. NO nitrogen monoxide
c. NH3 nitrogen trihydride (ammonia)
d. (NH4)2S
e. Pt(SO4)2
f. H3PO4
ammonium sulfide
platinum (IV) sulfate
phosphoric acid
6. Write the formulas for the following compounds:
a. strontium phosphide
Sr3P2
d. carbon tetrahydride
CH4
b. zinc hydroxide
Zn(OH)2
e. phosphorous monoxide PO
c. hydrocyanic acid
HCN
f. iron (III) oxide
Fe2O3
7. What are the 6 reaction types and their patterns? Provide an example of each
type of reaction.
Synthesis –
A + B  AB
2H2 + O2  2H2O
Decomposition –
AB  A + B
Single Replacement Cationic - A + BC  B + AC
Cu + 2AgNO3  2Ag + Cu(NO3)2
Single Replacement Anionic – A + BC  C + BA
F2 + KBr  Br2 + KF
Double Replacement - AB + CD  AD + CB
Na2SO4 + BaCl2  2NaCl + BaSO4
2NaCl  2Na + Cl2
Combustion – Hydrocarbon + Oxygen  carbon dioxide + water
CH4 + 2O2  CO2 + 2H2O
8. What is a limiting reactant? Why is this reactant so important?
The limiting reactant is the reactant that runs out first in a chemical reaction,
therefore determining the amount of product produced.
9. What is an excess reactant?
The reactant that there is more than enough of to complete the limiting reactant.
Some of this reactant will be left over when the reaction stops. Usually, this reactant
is cheaper and easiest to isolate out of the possible reactants.
10. What does “theoretical” mean? Where/how are these results obtained?
Theoretical results show what the value of a calculation should be under perfect
conditions. These results can be obtained from a published source, teacher, or
through stoichiometry.
11. What does “experimental” mean? Where/how are these results obtained?
Experimental results show the value of a calculation that was obtained through lab
results. Hopefully, the theoretical and experimental results should as close to the
same as possible.
12. Using dimensional analysis, convert the following:
a. 2.00 moles of oxygen gas to grams
64.0 g O2
b. 6.75 x 1022 molecules of oxygen gas to grams
3.59 g O2
c. 4.66 g iodine crystals to molecules
1.11 x 1022 molecules I2
d. 7.6 x 1023 formula units of salt to moles
1.3 mol NaCl
13. What is the difference between a coefficient and a subscript? Provide an
example illustrating each.
A coefficient is placed in front of elements and compounds to make the number of
atoms on each side of the equation equal. 2H2O
Subscripts are used in chemical equations to show the number of atoms bonded in a
molecule or formula unit. 2H2O
14. What is the difference between a reactant and a product? Provide an example
illustrating each.
Reactants are found to the left of the arrow in a balanced chemical equation
2H2 + O2  2H2O
Products are found to the right of the arrow in a balanced chemical equation.
2H2 + O2  2H2O
15. What is a catalyst? Provide 3 examples that we frequently use in the lab.
A catalyst is a chemical or a process used to speed up a reaction. Examples include,
heating, agitation/stirring, adding a chemical that will not become part of the
products.
16. Explain how you know whether or not SR or DR reaction will occur. Provide an
example for SR and DR that will occur. Provide an example for SR and DR that will
not occur. (Use blue solubility sheet)
A SR reaction will occur if the element that is by itself is more reactive (higher up)
on the reactivity chart then the like element it is trying to replace in the compound.
If not, then no reaction will occur.
Ag + NaCl  Na + AgCl
NO RXN
A DR reaction will occur if the partner swap due to mobile ions mingling will result
in gas, water, or a precipitate will form. If not, only spectator ions are present and
no reaction will occur.
NaCl + KBr  NaBr + KCl NO RXN
17. What is the % composition of each element in ammonium phosphate?
(NH4)3PO4
% N = 28.19%
% H = 8.128%
% P = 20.77%
% O = 42.92%
18. What is a hydrate? Anhydrate?
A hydrate is a solid that contains water molecules.
An anhydrate is the solid chemical that remains after the water has been removed
from the hydrated form of the compound.
19. What is the % composition of water in MgCO3  10H20?
% H2O = 68.123%
20. Compare empirical and molecular formulas. Provide an example of each.
Empirical formulas show the lowest/simples whole number ratio of atoms in a
compound. CH4
Molecular formulas show the actual or true number of atoms in a compound. C2H8
21. 11.0 g of a certain compound contains 2.82 g of magnesium and 8.18 g of
chlorine. What is the empirical formula?
MgCl2
22. A compound is tested and is found to be composed of 43.7% phosphorus and
56.3% oxygen. It has a molecular mass of 425.82 g/mol. Is the empirical and
molecular formula the same? Provide formulas.
No, the formulas are not the same. The empirical formula is P2O5. The molecular
formula is 3 times as large in mass and atoms, P6O15.
23. A solution of magnesium chloride and silver nitrate are mixed:
a. Write a balanced chemical equation with states for the reaction.
MgCl2(aq) + 2AgNO3(aq)  Mg(NO3)2(aq) + 2AgCl(s)
b. What type of reaction is it?
Double replacement
c. Write a complete balanced equation (circle spectators).
Mg+2(aq) + 2Cl-(aq) + 2Ag+(aq) + 2NO3-(aq)  Mg+2(aq) + 2NO3-(aq) + 2AgCl(s)
d. Write a net ionic equation.
2Cl-(aq) + 2Ag+(aq)  2AgCl(s)
24. What are spectator ions?
Spectator ions are ions that watch throughout the entire chemical reaction. They
are not involved in forming the precipitate.
25. Why is a net ionic equation so important?
This equation is what shows what ions hook up in solution to form the precipitate
that drives the chemical reaction.
26. For each set of reactants, identify the type of reaction, predict the product(s) in
words and then write a balanced equation.
a. Potassium + Oxygen  Potassium Iodide
2K + O2  2KI
Synthesis
b. Fluorine + Lead (IV) Bromine  Bromine + Lead (IV) Fluoride
2F2 + PbBr4  2Br2 + PbF4
Single Replacement Anionic
c. Aluminum Oxide  Aluminum + Oxygen
2Al2O3  4Al + 3O2
Decomposition
d. Calcium + Gold (I) Oxalate  Gold + Calcium Oxalate
Ca + Au2C2O4  2Au + CaC2O4
Single Replacement Cationic
e. Calcium Carbonate + Magnesium Phosphate  Calcium Phosphate + Magnesium
Carbonate
3CaCO3 + Mg3(PO4)2  Ca3(PO4)2 + 3MgCO3
Double Replacement
f. Tricarbon Octahydride + oxygen  Carbon Dioxide + Water
C3H8 + 5O2  3CO2 + 4H2O
Combustion
27. What is the difference between and ionic, covalent and metallic bond?
Ionic  metal + nonmetal (cation and anion) bonded through the transfer of
electrons (loss and gain)
Covalent  2 nonmetals bonded through sharing of electrons
Metallic  2 metal cations surrounded by a sea of electrons
28. Why do things bond?
To look like a noble gas and obtain a full valence shell
29. Draw the Lewis Dot Structure for each of the following ionic substances:
a. LiCl
b. MgBr2
c. Ca3P2
see additional key on Moodle
30. Draw the Lewis Dot Structure for each of the following covalent
substances:
a. Br2
b. O2
c. N2
d. CO2
see additional key on Moodle