Materials
(and others)
Practice Test
1. Describe the action of charged particles, such as Al3+ in the water treatment process of flocculation
2. A soap molecule CH3(CH2)4CHCH(CH2)6COO- was produced from a triglyceride
a)
Draw the structure of this triglyceride
b)
Describe how you can determine whether this triglyceride will be a fat or an oil
c)
Systematically name the by-product of the reaction that produces soap
d)
This reaction is an example of a basic hydrolysis, what name is given to this specific
reaction?
e)
Describe how this soap molecule enables it to dissolve grease
3. Describe how zeolites act as water softeners
4. Part of a polymer is shown below
O
||
(– C – (CH2)3 – O – )
a)
Draw the monomer for this polymer
b)
What type of polymerisation reaction is required to form this polymer
Another type of monomer is shown below
NH3 – (CH2)3 – NH3
c)
Name the type of monomer that would be required to form an amide polymer with this
monomer
d)
Draw a polymer using these two monomers, draw 2 repeating units (assume 1 carbon
between functional groups for the monomer from c)
e)
This polymer has a melting range of 290 – 300oC, why would it not have a precise melting
point
f)
Describe why the melting point of this polymer would be higher than polyethylene
g)
Polyethylene is a plastic polymer, what does this mean?
h)
How do the properties of a polymer change with cross linking
6. Tripolyphosphates can be used as additives in cleaning products
a)
Draw the Linear tripolyphosphate anion P3O105-
b)
Write the molecular formula of the magnesium salt of this ion
c)
Would this compound be a solid, liquid or gas?
d)
State the arrangement of oxygen atoms around each phosphorus atom
e)
Describe 3 advantages of using tripolyphosphates with detergents
f)
Describe an environmental concern for the use of tripolyphosphates
7. Silicates are the main component of many soils
a)
Write the formula for the anion of MgAl2(SiO3)4
b)
Calculate the charge on the anion Al3Si2O10.3H2O
c)
Calculate the percentage of silicon atoms that have been replaced by aluminium in the
previous aluminosilicate
8. HOCl is commonly used as a disinfectant in pools
a)
Name this chemical
b)
Write an equation for the formation of this chemical
c)
How would acid rain affect this reaction
d)
The pool requires a concentration of 1%w/v HOCl
i. Convert this to gL-1
ii.
If the pool contains 200L calculate the mass of HOCl required
iii.
If the Kc for this reaction is 1.0, calculate the molL-1 of OCl-1 required
iv.
If the NaOCl solution was initially 40%, what volume would be needed to chlorinate the
pool?
9. Soils rich in limestone (calcium carbonate) are resistant to the effects of acid rain. One sample of
soil was analysed by titration to determine the amount of limestone.
Step 1:
Step 2:
100g of soil was covered with 500mL of 2M HCl and allowed to react completely
The excess HCl was titrated with 0.5M NaOH
a)
Write a balanced equation for the reaction in Step 1
b)
Calculate the number of moles of HCl added in Step 1
The average titre value for Step 2 was 39.1 mL
c)
Write a balanced equation for the reaction in Step 2
d)
Calculate the number of moles of NaOH used in Step 2
e)
Hence calculate the number of moles of excess HCl left from Step 1
f)
Using your answers to parts b) and e), calculate the amount of HCl that reacted in Step 1
g)
Hence calculate the number of moles of CaCO3 in the original sample
h)
Calculate the %w/w of CaCO3 in the original soil sample