chapter 9 review assignment - mrs....

Chemistry 11 Unit 6 - Solutions

Unit 6 Review – Answer KeyRead pages 193 – 212 and answer the following questions

1. What is solution chemistry?The study of chemical reactions in solution (not solely solid, liquid or gas states)

2. How are the terms SOLUTION, SOLVENT , SOLUTE, SOLUBLE and SOLUBILITY related?

A SOLUTE dissolves in a SOLVENT to produce a SOLUTION SOLUBILITY is how much of a solute will dissolve in a measured amount

of solvent at a specific temperature SOLUBLE means that a solute is able to dissolve in a solvent

3. When is a solvent SATURATED or UNSATURATED? SATURATED means the maximum amount of solute possible has

dissolved and some undissolved solute remains UNSATURATED means that more solute could still dissolve

4. What pieces of information must be present to specify solubility? Amount and type of solute Amount and type of solvent Temperature of the solution

5. Circle the compound that will CONDUCT electricity.

H2SO4(aq) KCl(s) AgNO3(aq) Zn(s)

LiOH(aq) C6H8OH(l) Ba(OH)2(s) I2(l)

6. What is the MAIN difference between dipole-dipole and London forces? Dipole-dipole is an attraction between permanent separation of charges

within molecules (dipoles) caused by the molecule being asymmetrical. London forces are an attraction between a temporary separation of

charge, created by the repulsion between electrons on neighbouring atoms

Dipole-dipole attractions are much stronger than London forces

7. If a permanent dipole is present which force will be present? _dipole-dipole force_

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8. If a permanent dipole is not present which force will be present? __London force_

9. Explain what creates London forces. Give examples to support your explanation

As neutral atoms or molecules move close to each other, the electrons on one will repel the electrons on the other

This creates a temporary uneven distribution of electrons, making one side of the atom/molecule temporarily positive and the other side temporarily negative

The attraction between these temporary, partial charges is a London force

10. What makes a molecule asymmetrical? Give an example. An uneven distribution of charge or sharing of electrons Caused by bonds between atoms with differing electronegativities Eg, H2O

11. Asymmetrical molecules are said to be __POLAR__(Polar/ Non-polar) molecules.

12. What makes a molecule symmetrical? Give an example. An even distribution of charge or sharing of electrons Caused by bonds between atoms with the same electronegativities Eg, CCl4

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13. Symmetrical molecules are said to be _NON-POLAR_ molecules.

14. How can you use the above information to compare different molecules boiling points? Give an example.

Molecules/atoms with stronger bonds will have higher boiling pointso Dipole-dipole forces are stronger than London forceso If London forces are the only force present, then the larger the #

electrons, the stronger the London forceo Eg. HF vs. F2

HF has a higher BP as it has dipole-dipole forces while F2 only has London forces to break

15. How are hydrogen bonding different from London forces? H-bonding is an extremely strong type of a dipole-dipole force. Only occurs when H is covalently bonded to N, O or F Is the result of a permanent dipole within the molecule whereas London

forces result from temporary dipoles

16. Explain the phrases “like dissolves like” Polar solvents will dissolve polar or ionic solutes as the polar solvents’

permanent dipoles will attract the permanent dipole or ionic charge in the polar or ionic solute. These attractions are strong enough to separate the solute molecules from each other

Polar solvents will not dissolve non-polar solutes as there are no charges on the non-polar solute to be attracted to the solvent. The solvent, therefore, stays bonded/attracted to itself and does not dissolve the solute

Non-polar solvents cannot dissolve ionic or polar solvents as their London forces are not strong enough to pull apart the solute bonds

Non-polar solvents CAN dissolve non-polar solutes as the London forces of the solvent to solute are strong enough to pull the solute molecules apart.

See page 205 in your textbook for more info!

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17. Both funnels contain CCl4 and water. The CCl4, having a greater density, is the lower layer. Both CCl4 and water are clear and colourless. I2

and KMnO4 are both Purple solids.

Explain what you will see if:a. I2 crystals are added to the first

funnel.b. KMnO4 crystals are added to

the second funnel.

18.Write an equation showing what happens when each of the following are dissolved in water:

a) Na2SO4(s) ; …………..Na2SO4(s) 2Na+(aq) + SO42-(aq)

b) Ca3(PO4)2(s); ............Ca3(PO4)2(s) 3Ca2+(aq) + 2PO43-(aq)

c) KCl(s) ;..........…...........KCl(s) K+(aq) + Cl-(aq)

19. When ionic solutions are formed, the material dissolving breaks up into _IONS.

20. These are free to move around and therefore will conduct a n electric current__

21. What is the [Pb2+] in PbBr2 solution if the [Br -] is 0.0030 M.

PbBr2 Pb2+ + 2Br-

0.0015M 0.0015M 0.0030M

22. Calculate the concentrations of the ions if 250.0 mL of 3.0 x 10-4 M Ba(NO3)2 is mixed with 350.0 mL of 0.0020 M Na2SO4 solution.

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23. Calculate the concentrations of the ions if 3.8 grams of Ca(NO3)2 is added to 250.0 mL of 0.0050 M Na2SO4 solution.

24. Calculate the concentrations of the ions if 500.0 mL of 2.0 x 10-4 M Pb(NO3)2 solution is mixed with 800.0 mL of 3.0 x 10-3 M NaI solution.

25. Label the following as either Soluble (S) or Low solubility (LS)

a) RbCl _Solubleb) NaOH _Soluble_c) FeSO4 _Soluble_d) Ba(OH)2 _Low Solubility_

26. Write out the net ionic reaction for the following low solubility compounds

a) CuCl2 (s) Cu2+(aq) + 2Cl-(aq) CuCl2(s)

b) PbI2 (s) Pb2+(aq) + 2I-(aq) PbI2(s)

c) MgSO4 (s) Mg2+(aq) + SO42-(aq) MgSO4(s)

d) Ba3 (PO4)2 (s) 3Ba2+(aq) + 2PO43-(aq) Ba3(PO4)2(s)

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27. An aqueous solution of Cr(NO3)2 is mixed with an aqueous solution of K2CO3 a) Write a balanced formula equation for this reaction. (Include all subscripts.)

Cr(NO3)2(aq) + K2CO3(aq) 2KNO3(aq) + CrCO3(s)

b) The net ionic equation is:

Cr2+(aq) + CO32-(aq) CrCO3(s)

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chapter 9 review assignment - mrs....

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