Review Problems Chapter 4 PDF

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General Chemistry- Review Problems Chapter 4 for Chapter 4 Quiz...

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REVIEW PROBLEMS CHAPTER 4 Molecules and Compounds The following are review exercises for Exam I. These exercises are provided for you to practice or test yourself for readiness for the exam. These exercises represent many of the types of problems you would be expected to solve on the exam, but are not meant to represent all possible types of problems that could appear on the exam. 1. Write the Lewis dot symbol for: Na

Mg

Al

Si

2. Write the Lewis dot symbol for each atom or ion. Al

P

S

Al3+

Cl

Ar

Cl-

Cl

Mg

N

N 3-

3. Use Lewis dot symbols and arrow to show the movement of electron during the formation of the ionic compound. a) Na and Cl

b) Ba and N

c) Al and O

Give the empirical formula of the compound a):____________; b):_____________; c:___________. 4. An element, E, has the electronic configuration [Ne] 3 s23p1. Write the formula of its compound with the phosphate ion. 5. List the 7 diatomic elements and draw their Lewis structures. 6. Which of the following ions are likely to be found in stable ionic compounds? a) ClO3 -

b) P3-

c) Mg2+

d) Li+

e) Al2+

f) N2-

g) SO43-

h) PO33-

7. An ionic compound has the formula M2(NO3)2(PO4)2. What is the net charge on the metal ion (M) in this compound? 8. Classify each compound as ionic or molecular. a) SO2

b) NaI

c) MgO

d) NaNO3

9. Explain the following trends in lattice energy.

e) NH4Cl

f) NH4ClO4

g) NO2

a) NaCl < RbBr < CsBr

h) KClO4

b) BaO < KF

10. Match each of the following compounds with its lattice energy: KI, LiF, MgF2, LiI

j) CH4

h) N2O4

c) MgO < MgCl2

-2961, -1046, -759, -645 kJ/mol

11. You discover a new set of polyatomic anions that has the newly discovered element “X” combined with oxygen. Since you made the discovery, you get to choose the names for these new polyatomic ions. In developing the names, you want to pay attention to convention. A colleague in your lab come up with a name that she really likes for one of the ions. How would you name the following in a way consistent with her naming? Formula

12. Complete.

Name

XO 24

Cation

Anion

Name

Formula

Ammonium nitrite BaS Aluminum sulfate Iron(III) chloride 2+

Ca

N3Ca3N2 Mg(OH)2

Al3+

CO32-

Cr3+

SO32-

Vanadium(IV) phosphate

XO 23 XO 22

XO2-

Excite

13. Complete. Compound Co2S3

Name

Compound ClO2

Name

Compound Na2SO3

(NH4)2SO4

ClO2-

Ba(OH)2

FeCl2

NH4BrO4

S 2F 6

-

+

Br2

Br

H

IO-

NO2-

Ca3N2

Ca

N2O

AlPO4

P 2O 3

N3-

AlP

C2H2 Al2O3

NO NaClO

NaNO3

(NH4)2Cr2O7

NO

Cr2O3

MgCO3 ·5 H2O

CrO

2+

NH4

+

Name

H3O+ KHCO3

P 3O 5

CaO

C4H10

C2H4

C3H8

NH3

Fe(BrO2)3

K3PO4

CrCl3

KClO

P4O6

14. Complete Name

Formula

Name

Formula

Name

Barium fluoride

Sulfide ion

Barium hydroxide

Chromium (III) sulfide

Sulfite ion

Nitride ion

Lithium carbonate

Sulfate ion

Manganese(IV) oxide

Aluminum sulfite

Tetraphosphorus hexafluoride

Copper(II) sulfide

Aluminum perchlorate

Nitrite ion

Aluminun bromide

Nitrogen triiodide

Barium nitrate trihydrate

Chromium(III) sulfate

Methane

Ethene

n-Butane

Hydrogen cyanide

Lithium bisulfate

Carbon tetrachloride

Ammonium ion

Sodium chromate

Sodium dihydrogen phosphate

Ammonium phosphate

Nitrate ion

Chromium(III) sulfate heptahydrate

Disulfur tetroxide

Tin(IV) oxide

Aluminum nitride

n-Pentane

Propane

Ethyne

Iron(II) cyanide

Copper(II) phosphate

Chlorine molecule

Nitrogen molecule

Dichlorine monoxide

Aluminum hydroxide

15. Consider aluminum sulfate. (a) What is the empirical formula:__________________; Calculate its molar mass:______________. (b) Calculate the mass percent of oxygen. (Ans. 56.1%) (c) What mass of oxygen (in gram) is there in 8.50 g aluminum sulfate? (Ans. 4.77 g) (d) Calculate the mass of aluminum sulfate that contains 9.14 x 10 22 oxygen atoms. (Ans. 4.32 g ) (e) How many atoms of oxygen are there in 8.50 g aluminum sulfate? (Ans. 1.73 x 1023 atoms O)

Formula

(f) Calculate the total number of atoms in 48.0 g aluminum sulfate.

(g) What mass of sulfur comes with 22.5 g of O in aluminum sulfate? 16. Calculate the volume (mL) of Br2 liquid (density = 3.12 g/mL) needed to provide 5.79 x 10 24 molecules of carbon tetrabromide. (Ans. 986 ml) 17. Calculate the number of molecules of O 2 required to make 1.44 g of KHCO3 (Ans. 1.30 x 1022 molecules O2) 18. A compound X3O4 is 72.36% X by mass. What is the molar mass of X in g/mol? (Ans. 55.85 g/mol) 19. Hemoglobin, the oxygen-carrying protein in red blood cell, has 4 iron atoms per molecule and contains 0.40 % iron by mass. Calculate the molar mass of hemoglobin. (Ans. 5.6 x 104 g/mol)

20. A compound contains 49.32% C, 43.83%O, and 6.85% H by mass. What is the empirical formula? ( Ans. C3H5O2)

21. For the following compounds whose molecular formulas are given, indicate the empirical formula: a) C6H12O6 glucose

b) C3H6O3 actic acid

c) C12H4Cl4O2 dioxin

22. A compound is 57.19 %S and 42.81 % O. Its molar mass is 224 g/mol. What is its molecular formula? ( Ans. S 4O6)

23. The analysis of a salt shows that it contains 15.78% aluminum (Al); 28.08% sulfur (S); and 56.12 % oxygen (O). a)

What is the empirical formula for this substance? ______________

b) The compound contains sulfate ions only. Determine its formula unit. _________________ 24. A 0.4647 g sample of a compound known to contain only carbon, hydrogen, and oxygen was burned in oxygen to yield 0.8635 g of CO2 and 0.1767 g H2O. a) What is the empirical formula of this alcohol? (Ans. C3H3O2) b) The molar mass of the compound is 284 g/mol. What is the molecular formula? ( Ans. C12H12O8)

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25. An 8.129 g sample of MgSO4 x H2O is heated until all the water of hydration is driven off. The resulting anhydrous compound,

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MgSO4, weighs 3.967 g. What is the formula of the hydrate? (Ans. MgSO 4 7 H2O) 26. Potassium sulfate contains 44.9% potassium by mass. How many moles of potassium are in a 50.0 g sample of potassium sulfate? (Ans. 0.574 mol) 27. To produce Mn(ClO4)x, 3.62 g of ClO4 are needed for every 1.00 g of Mn. What is x? (Ans. x = 2 )...