Practice 4.3.5

[lawson...@yahoo.com]

**I'm not done. This is what I have so far.**
4.3.5 Practice: Chemical Reactions
Practice Assignment

Chemistry (S1392845)
Lawson Durham
Points possible: 25
Date: ____________

Question 1: The Mole (4 points)

a. Match the following terms to their definitions. (2 points)

A. Mole _A__ The number of items in a mole
B. Molarity _C__ Mass of 1 mole of something
C. Molar mass _D__ 6.02 × 1023 items
D. Avogadro's number _B__ Concentration of a dissolved substance
b. Match the following terms to their units. (1.5 points)

A. Atomic mass __C_ mol/liter
B. Molarity __A_ amu
C. Molar mass _B__ g/mol
c. What is the relationship between the atomic mass of an element and a mole of that element's atoms? (.5 point)

Atomic mass is grams per mol. For instance if you have one mol of Oxygen and its atomic mass is 15.9994 g/mol, then you have 15.9994 grams of Oxygen.










Question 2: Unit Conversions (2 points)

Use the periodic table to answer the following questions. (Round atomic masses to the nearest tenth unit.) (4 points)

a. What is the molar mass of Fe(NO3)2? (.5 point)


179.8548 g/mol









b. What is the number of moles of 27.6 g of lithium (Li)? (.5 point)



3.976372280651203








c. What is the number of molecules of 140 g of CO? (.5 point)




4.9981970789100005







d. What is the molarity of 48.6 g of magnesium (Mg) ions in 2 L H2O? (.5 point)


Molarity = 1.0M









Question 3: Empirical and Molecular Formula (1 point)

a. What is the difference between the empirical formula and the molecular formula? (.5 point)


the empirical formula has the smallest whole number for their subscript whereas the molecular formula is the actual number of molecules or atoms in a compound.









b. How does one determine the molecular formula from the empirical formula? (.5 point)


molar mass over grams of element









Question 4: Percent Composition (3.5 points)

a. How is the percent composition by mass determined? (.5 point)



Find the molar mass of the compound by adding up the masses of each atom

in the compound using the periodic table or a molecular mass calculator.
Calculate the mass due to the component in the compound you are for which

you are solving by adding up the mass of these atoms.
Divide the mass due to the component by the total molar mass of the compound

and multiply by 100.








b. Determine the percent composition of each element in MgCl2. (1 point)

i. Magnesium (Mg): (.5 point)



25.5330322445121








ii. Chlorine (Cl): (.5 point)












c. Calculate the empirical formula from the given percent compositions.
82% nitrogen (N), 18% hydrogen (H) (2 points)












Question 5: Chemical Equations (8 points)

a. Identify the different parts of the chemical equation below. (4 points)

A(s) + B(l) C(g) + D(aq)

1. A: _________________________ 5. (s): _________________________
2. B: _________________________ 6. (l): _________________________
3. C: _________________________ 7. (g): _________________________
4. D: _________________________ 8. (aq): _________________________
b. Match each type of chemical reaction to the general form of the equation describing it. (2 points)

A. Single replacement ___ AB + CD AD + CB
B. Decomposition ___ AB + C CB + A
C. Double replacement ___ A + B AB
D. Synthesis ___ AB A + B
c. Use the activity series of metals to predict the products of the following single-replacement reaction. Explain your answer. (1 point)

NiCl2 + Fe












d. Use the solubility table to predict if a precipitate will form in the double-replacement reaction.

CuSO4 + 2KOH Cu(OH)2 + K2SO4

Explain your answer. (1 point)












e. Label the states of each compound in the reaction below.

CuSO4( ) + 2KOH( ) Cu(OH)2( ) + K2SO4( )












Question 6: Chemical Reactions (1.5 points)

a. How can one tell if a chemical reaction is balanced? (.5 point)


If it is balanced then the mass (amount) of elements on each side of the arrow will be equal.
H2 + O2 -> H2O2









b. What information does a complete ionic equation give that the balanced equation doesn't show? (.5 point)


The balanced equations give the details of the reactants and products.
An ionic equation shows only those elements that react, and not the spectator ions.









c. What information does a net ionic equation give that the complete ionic equation does not show? (.5 point)












Question 7: Combustion (2 points)

a. What two reactants are necessary in order for a hydrocarbon combustion reaction to take place? (.5 point)












b. What three products are necessary in order for a hydrocarbon combustion reaction to take place? (.5 point)












c. Complete the following combustion reaction. Write your balanced equation two different ways. (1 point)

C8H18 + O2

C8H18 + O2












Question 8: Drawing Hydrocarbons (3 points)

Use the pictures shown to identify three ways of drawing hydrocarbon molecules. Then write the molecular formulas. (1 point each)

a.












b.












c.

[sue.wi...@apps.cabarrus.k12.nc.us]

[sue.wi...@apps.cabarrus.k12.nc.us]

On Monday, November 26, 2012 9:12:49 AM UTC-5, lawson...@yahoo.com wrote:

[sue.wi...@apps.cabarrus.k12.nc.us]

Lawson, I had already graded most of the work you had completed. Some  how I logged off the page and cannot reply to you post again. I must see formulas and you must show all your work for credit.

On Monday, November 26, 2012 9:12:49 AM UTC-5, lawson...@yahoo.com wrote:

[sue.wi...@apps.cabarrus.k12.nc.us]