CHEM126 – BASIC REVIEW – CH.1-8

 

BASIC REVIEW CH.1-8

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Question 1

 

How many protons does copper have?

Periodic Table and protons

 

 

 

Explanation

Periodic Table

Question 2

 

How many electrons does copper have? Remember atoms are neutral.

 

 

Question 3

 

How many neutrons does copper-63 have? Help given in feedback.

 

 

Explanation

Remember the protons and neutrons constitute most of the mass of an atom. For example, iron-56 has an approximate mass of 56 g per mol. Per atom, there are 26 protons and 56-26 = 30 neutrons.

Question 4

 

What is the mass of 1 mol of CO2 in g?
Molar mass example
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Explanation

Molar Mass of CO2 = 44 g

1 mol of CO2 =  x g / 44 (g/ mol)

Question 5

 

What is the mass of 39 molecules of SO3 in g?

Using Avagadro’s Number

 

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Explanation

39 molecules / (6.022*10^23)  * 80.066 = 5.18e-21

(molecules/ Avogadro’s #) * MolarMass(g)

 

Question 6

 

Correctly match the element with the property.
Periodic Table and Group IA and IIA metals
Metal that reacts with cold water to produce OH- and H2(g)Choose…CrNaSSiHe chem126-rev1-8 - Fluff Butt ReviewsMetal (all conduct electricity)–no reaction with water, but reacts with acid to produce H2 gasChoose…CrNaSSiHe chem126-rev1-8 - Fluff Butt ReviewsNon-metal–does not conduct electricityChoose…CrNaSSiHe chem126-rev1-8 - Fluff Butt ReviewsNoble gas–inert, stable electron configurationChoose…CrNaSSiHe chem126-rev1-8 - Fluff Butt ReviewsSemimetal–poor conductor of electricityChoose…CrNaSSiHe chem126-rev1-8 - Fluff Butt Reviews

 

 

 

Question 7

 

What is the correct formula for aluminum sulfide?
Oxidation states
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Explanation

Al 3+;  S2-

Al2S3

Question 8

 

Which compound is the most ionic?

Ionic Compounds

 

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Explanation

Ionic compounds-

Question 9

 

Match properties correctly

Quantum Numbers

 

Indicates energy and size of orbitalChoose…pnfd2s chem126-rev1-8 - Fluff Butt Reviewsl=0Choose…pnfd2s chem126-rev1-8 - Fluff Butt Reviewsl=1Choose…pnfd2s chem126-rev1-8 - Fluff Butt Reviewsl=2Choose…pnfd2s chem126-rev1-8 - Fluff Butt Reviewsl=3Choose…pnfd2s chem126-rev1-8 - Fluff Butt ReviewsNumber of possible electron spins for each orbitalChoose…pnfd2s chem126-rev1-8 - Fluff Butt Reviews

 

 

Explanation

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Question 10

 

Select the correct set of quantum mechanical numbers for an electron in an s, p, d, and f orbital. (4 correct answers.)

Allowed Combination of Quantum Numbers

 

Select one or more: chem126-rev1-8 - Fluff Butt Reviews chem126-rev1-8 - Fluff Butt Reviews chem126-rev1-8 - Fluff Butt Reviews chem126-rev1-8 - Fluff Butt Reviews

 

 

Explanation

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Question 11

 

Correctly match the information for the angular momentum quantum number (l) which gives the shape of the orbital. A nodal plane is a region where the electron density is zero, that is, the probability of finding the electron there is zero.
The maximum number of electrons in an electron orbital.Choose…dspf2 chem126-rev1-8 - Fluff Butt ReviewsSpherically symmetric orbital–no nodal planesChoose…dspf2 chem126-rev1-8 - Fluff Butt ReviewsOrbital shaped like a peanut or dumbbell–one nodal planeChoose…dspf2 chem126-rev1-8 - Fluff Butt Reviews4 of the 5 orbital shaped like a double peanut–2 nodal planesChoose…dspf2 chem126-rev1-8 - Fluff Butt ReviewsOrbital shaped like flower or fancy–3 nodal planesChoose…dspf2 chem126-rev1-8 - Fluff Butt Reviews

 

 

Explanation

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Question 12

 

What is the ground-state electron configuration for S?

Electron Configurations

 

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Explanation

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Question 13

 

What is the electron configuration for S2-?
Electron Configurations Negative Ions
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Explanation

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Question 14

 

What is the electron configuration for K1+?
Electron Configurations Positive Ions
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Explanation

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Question 15

 

Match atomic radius from largest to smallest.

Atomic Radius

 

KChoose…Second largest atomic radiusThird largest atomic radiusFourth largest atomic radiusLargest atomic radiusSmallest atomic radius chem126-rev1-8 - Fluff Butt ReviewsAlChoose…Second largest atomic radiusThird largest atomic radiusFourth largest atomic radiusLargest atomic radiusSmallest atomic radius chem126-rev1-8 - Fluff Butt ReviewsNaChoose…Second largest atomic radiusThird largest atomic radiusFourth largest atomic radiusLargest atomic radiusSmallest atomic radius chem126-rev1-8 - Fluff Butt ReviewsArChoose…Second largest atomic radiusThird largest atomic radiusFourth largest atomic radiusLargest atomic radiusSmallest atomic radius chem126-rev1-8 - Fluff Butt ReviewsSChoose…Second largest atomic radiusThird largest atomic radiusFourth largest atomic radiusLargest atomic radiusSmallest atomic radius chem126-rev1-8 - Fluff Butt Reviews

 

 

Explanation

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Question 16

 

Match ionization energies from smallest to largest.

Ionization Energy

 

KChoose…Third smallest ionization energyFourth smallest ionization energyLargest ionization energySmallest ionization energySecond smallest ionization energy chem126-rev1-8 - Fluff Butt ReviewsAlChoose…Third smallest ionization energyFourth smallest ionization energyLargest ionization energySmallest ionization energySecond smallest ionization energy chem126-rev1-8 - Fluff Butt ReviewsNaChoose…Third smallest ionization energyFourth smallest ionization energyLargest ionization energySmallest ionization energySecond smallest ionization energy chem126-rev1-8 - Fluff Butt ReviewsArChoose…Third smallest ionization energyFourth smallest ionization energyLargest ionization energySmallest ionization energySecond smallest ionization energy chem126-rev1-8 - Fluff Butt ReviewsSChoose…Third smallest ionization energyFourth smallest ionization energyLargest ionization energySmallest ionization energySecond smallest ionization energy chem126-rev1-8 - Fluff Butt Reviews

 

 

Explanation

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Question 17

 

What is the correct formula for iron (III) oxide?
Multiple oxidation states
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Explanation

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Question 18

 

Which of the following tin (IV) compounds makes sense using oxidation states and conservation of charge?

Oxidation State and Polyatomic Ions

 

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Explanation

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Question 19

 

Warmup question. How many moles of Ca(OH)2 are required to neutralize (react completely with) 0.89 moles of HCl? The balanced reaction is:

2HCl(aq) + Ca(OH)2(aq) → 2H2O(l) + CaCl2(aq)

Using Balanced Equations

 

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Explanation

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Question 20

 

What volume in L of 0.35 M Ca(OH)2 is required neutralize 0.39 moles of HCl? The balanced reaction is:

2HCl(aq) + Ca(OH)2(aq) → 2H2O(l) + CaCl2(aq)

Using Balanced Equations II

 

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Explanation

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Question 21

 

What volume in L of chlorine at 30oC and 611 torr is required to react completely with 3.72 g aluminum:

2Al(s) + 3Cl2(g) → 2AlCl3(s)

Calculate the moles chlorine needed (as in the previous problem), then use the ideal gas law–PV = nRT. Additional help is given in the feedback.chem126-rev1-8 - Fluff Butt Reviews

 

 

Explanation

Procedure: g Al –> mol Al –> mol Cl2. Next solve for V in PV = nRT. Did you remember to convert torr to atm and oC to K?

Question 22

 

The following reaction takes place at a certain elevated temperature:

Fe2O3(s) + 3CO(g) → 2Fe(l) + 3CO2(s)

What is the percent yield of iron if 41.1 g Fe2O3 in excess CO produces 25.0 g Fe? The M.W. of Fe2O3 is 159.7 g/mol and the M.W. of CO is 28.01 g/mol.

Recall that the percent yield is the actual yield divided by the theoretical yield times 100%. Additional help is given in the feedback.
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Explanation

Procedure: g Fe2O3 –> mol Fe2O3 –> mol Fe –> g Fe (This is the theoretical yield. Note M.W. CO is not used.) Take actual yield, 25.0, and divide by the theoretical yield and then multiply by 100 (to change to percent yield).

Question 23

 

What is the mass percent of carbon in sugar, C12H22O11? M.W. sugar = 342 g/mol.

Help is given in the feedback.
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Explanation

Mass percent C = (mass C/ total mass) x 100%. Pick 1 mol sugar. What is the mass? How many mol C in 1 mol sugar? What is the mass C?

Question 24

 

Analysis of 3.500 g sample of an unknown compound shows that it contains 1.400 g C, 0.235 g H, and the rest O. What is the empirical formula of this compound?

Hint, given in feedback.
Select one: chem126-rev1-8 - Fluff Butt Reviews

 

 

Explanation

Because total mass is conserved, the mass of O can be found. Convert each mass to moles. Convert moles to smallest whole numbers. Sometimes it is sufficient to divide each by the smallest number of moles. Compare the number of moles of each element in the compound.

Question 25

 

Hemoglobin has a mass of about 67,000 g/mol. It is 0.3335% iron by mass. How many iron atoms are in a molecule of hemoglobin?

Help is given in the feedback.chem126-rev1-8 - Fluff Butt Reviews

 

 

Explanation

Find mass of iron in 1 mole of hemoglobin. Divide by M.W. of iron. This gives moles of iron in 1 mole of hemoglobin. It equals the atoms of iron in 1 molecule of hemoglobin.

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