CHEM191 Practice Test 2
Quiz instructions
Question 1 4 pts
What is the difference between an exothermic reaction and an endothermic reaction. Explain how the temperature of the surroundings changes with an exothermic and endothermic reaction
Question 2 3 pts
The following picture shows the reaction of zinc metal with and aqueous solution of hydrochloric acid to produce hydrogen gas.
Provide TWO ways that the reaction components could be changed in order to make the reaction produce the gas at a faster rate. Justify your answer using collision theory.
Question 3 3 pts
Explain, what a catalyst is and how does it speed up a reaction
Question 4 1 pts
Identify the type of reaction is shown below?
Displacement
Exchange
Decomposition
Combination
Question 5 1 pts
The following pairs of aqueous solution are mixed, which WILL result in the formation of a precipitate?
zinc sulfate + sodium chloride
lead nitrate + calcium chloride
ammonium sulfate + sodium nitrate
lithium oxide + sodium chloride
Question 6 3 pts
Explain why the following equaton below forms Fe(OH)3 as a solid precipitate and an aqueous soluton of NaCl. Justfy your answer by referring to the solubility rules and identfy the spectator ions.
Question 7 1 pts
What is the oxidation number of each iron atom in Fe2O3 ?
+6
-2
+3
-3
Question 8 2 pts
In the balanced redox equation below, which species is the oxidant and reductant (respectively)?
Mg + H2SO4 → MgSO4 + H2
Mg, H2SO4
H2, MgSO4
Mg, H2
H2SO4, Mg
Question 9 1 pts
Which of the following is a correct expression for the equilibrium constant K for the equilibrium reaction below?
A
B
C
D
Question 10 1 pts
The equilibrium constant for the reaction,
What is the equilibrium constant for the reaction shown below under the same conditions?
600
4.95
49
0.0408
Question 11 1 pts
In the reaction below, which one of the sets below constitutes an acid-conjugate base pair?
H2O, H3O+
H2PO4
-
, H2O
H2PO4
-
, H3O+
H2PO4
-
, HPO4
-2
Question 12 2 pts
Explain, using the definitions of strong and weak acids, why the picture below for Solution 3 represents a strong acid and that for Solution 2 represents a weak acid.
Question 13 2 pts
Identify the functional groups marked (i) to (iv) in the molecular structure given below.
Question 14 4 pts
Give the systematic name for the following three organic compounds
Question 15 1 pts
Identify the type of reaction occurring below:
Substitution
Oxidation
Addition
Esterification
Question 16 1 pts
Identify the type of reaction occurring below:
Substitution
Oxidation
Addition
Elimination
Question 17 2 pts
Identify the reagents A and B required to carry out the following reactions
Question 18 1 pts
What do these hazard lables represent?
Ecotoxic, Flammable
Corrosive, Flammable
Toxic, Oxidiser
Ecotoxic, Oxidiser
Question 19 1 pts
It is important to remove the funnel from a burette because:
It might hinder the reading of the burette.
It might add impurities to the solution
It might add a drop of solution and change the reading
It might cause the burette to tip over.
Question 20 35 pts
You should write your answers out, scan them to make a pdf file and then upload your file. This will need to be completed within the given time frame.
a .Calculate the value of ∆ H of reaction for (show your working):
Using the bond enthalpies, Δ H (kJ mol ):
C-C +346 C-H +414 H-H +436 CtriplebondC = +839
b .Calculate the energy (kJ) absorbed when 250 g of carbon monoxide decomposes to produce carbon and oxygen. M(CO) = 28 gmol-1
c. Balance the following redox equations using the half equation method
d.The production of methane gas (CH ) from carbon and hydrogen gas is an equilibrium reaction.
Describe the effect of each of the following changes on the equilibrium concentration of methane (increase, decrease, stay the same). Justify your answers using Le Chatelier’s principles
i. H2 gas is removed
ii. Decreasing the temperature of the reaction mixture
iii. The pressure of the system is increased
e. A solution of sulfuric acid, H SO (aq), has concentration of 0.0056 mol L-1. Calculate the following:
i. the [OH ] concentration Kw = 1.00 x 10-14
ii. the pH and indicate if it is acidic or basic
f. Draw the structural formula of the following organic compounds
i.1-chloro-1-methylcyclohexane
ii.2-methylbutanoic acid
iii. 4-ethylhexan-3-ol
g. Draw the strutural monomer form. which this polymer could make
h.The molecule pent-2-ene, CH CH=CHCH CH , can exist as geometric isomers.
i.Draw the cis and the trans isomers .
ii. Explain why the molecule pent-2-ene has geometric isomers.
i. Write the structural formulae for Compounds 1 and 2, and give the names or formulae for Reagents, X, Y and Z.
j. Three 20.00 mL portions of sodium hydroxide, NaOH, were titrated with aqueous hydrochloric acid, HCl (aq), with concentration 0.1045 mol L-1. The following titres were obtained: 20.26 mL, 20.27 mL and 20.32 mL.
Calculate the concentration of the sodium hydroxide solution.