Chem 6th practice exam Essay

1

PRACTICE EXAM (not all questions pertain to a

certain mid-term). This is certainly taken from a youthful final

test.

1 . (4 pts) Permanganate ion oxidizes sulfide ion to important sulfur (which you should signify as a one S atom) and is decreased to MnO2 in basic solution. In the balanced equation for this response, which you will need to determine inside the work area, just how many water molecules and hydroxide ions are required in the final balanced formula?

Work area:

# of INGESTING WATER ____4______

# of OH- ___8_______

MnO4- + S2- ---> S + MnO2

x3

Oxidation:

S2- -----> S + 2eReduction:

4H+ + MnO4- + 3e- -----> MnO2 + 2H2O

x2

+

2acidic:

8H + 2MnO4 + 3S ------> 3S + 2MnO2 + 4H2O

But the question asks to balance in basic, as a result add the same no . of OH- since H+ to both sides, combine two types to become H2O and equilibrium no . of H2O by both sides

8OH- + 8H+ + 2MnO4- + 3S2- ------> 3S + 2MnO2 + 4H2O + 8OH8H2O + 2MnO4- + 3S2- ------> 3S + 2MnO2 + 4H2O + 8OH4H2O + 2MnO4- + 3S2- ------> 3S + 2MnO2 + 8OHNote My strategy is to harmony in acidulent solution each time and take care of OH- if fundamental solution is needed. If you are acquainted with the technique in the book (pp 488-489) for standard solution, make sure you follow these steps. Finally, we will end up with the same answer all things considered.

2 .

(5 pts) Info: ClO4- (aq) + 2 H+ (aq) + 2eAg+ (aq) & e-

Ag(s)

ClO3- (aq) + INGESTING WATER (l)

EВ° = plus1. 23 V

EВ° = +0. 70 V

Estimate the reaction division Q for a spontaneous effect using both of these half reactions if the prospect of the cellular is scored to be 0. 40 V.

Q sama dengan ___________________

Workshop:

Ecell sama dengan E0cell - RT/nF lnQ

Keys: Determine E0 and know how many e- require in the effect Spontaneous response need confident Ecell, while given (0. 40 V). Thus find out need to know which in turn reaction needs to be reduction or oxidation by comparing the given E0 half cellular. The more confident E0 is usually, the more likely to endure reduction. Through this problem the first reaction is reduction (more confident half cell), and the second need to be change to be the oxidized (b/c of less confident half cell potential). The 2nd E0 50 percent cell then simply change to become -0. 80 V. Sum up E0ox and E0red, you get E0 +0. 43 V, credit reporting that response is spontaneous no . of e- can be 2 through this reaction. (Don't forget to associate no . of e- pertaining to both half reaction) As a result,

0. 45 V = 0. 43 V - (8. 314 JK-1 5. 298 K) / ( 2 mol e- * 96500 C mol-1) lnQ Q = 10. 35

note 1 VC sama dengan 1 L

2

several.

(3 pts) Phosphonium bromide, PH4Br, thermally decomposes to create two molecules: a Lewis acid and a Lewis base.

The Lewis acid is: ______________ The Lewis base can be: ______________ 4.

(3 pts) Hydrazine can be described as binary compound of nitrogen with the formulation (a) in which N is present in the (b) oxidation express. It is formed when what other N-containing chemical substance (c) can be oxidized. Take note Binary compound composes of two different types of atoms, e. g. H2O (a) ___N2H4_______(b) ___each N offers Ox. number +2______

(c) _____ NH3____________

Hydrazine may be formed by NH3 (ammonia) being oxidized by H2O2 (hydrogen peroxide) 2NH3 + H2O2 в†’ H2N-NH2 + 2H2O (wikipedia)

5.

(4 pts) What acids are formed throughout the complete hydrolysis of PCl3 (a) and PCl5 (b). (a) __ H3PO3_(phosphorous acid)___

(b) __ H3PO4_(phosphoric acid)______

Hydrolysis: response with drinking water

PCl3 + 3 WATER в†’ H3PO3 + a few HCl (wikipedia)

PCl5 & 4 INGESTING WATER в†’ H3PO4 + 5 HCl (wikipedia)

6.

(3 pts) Offer an example of a known chemical substance compound consisting entirely of s- and/or p-block components that has a strange number of valence electrons.

_____NO_(nitrogenmonoxide)________

Normally, total no . of e- are actually for most substance, e. g. H2O (total e- = 10) NH3 ( total e- sama dengan 8). s- and p-block mean elements from group I-VIII in periodic desk. An example of the compound includes odd no . of e- coming from t and p orbital is NO (total number valence e- = your five + six = 11) 7.

(3 pts) Provide the formula for the simplest carbonyl complex predicted for rhodium (Rh). ________________________________

8....



News

 External and Internal Conditions Business Essay

External and Internal Conditions Business Essay

External and Internal Conditions By Dorothy Bruce Professor Ira Poladeen Business Capstone Apr 28, 2015 A great organization's environment includes factors…...

 importance of time Essay

importance of time Essay

Time is precious. It is invaluable. It is one of the highly effective factors. Our life is scored in terms of period. We grow in time, stay in…...

 Guns Are a Danger to Society Essay

Guns Are a Danger to Society Essay

Firearms are a Threat to Contemporary society Just imagine being placed in a movie theatre around night time and instantly some upset man will come in and starts…...

 Evaluate the Strengths and Weaknesses of the Concept of the Product Lifecycle. Choose Several Case Research Familiar to you personally. How Does the...

Evaluate the Strengths and Weaknesses of the Concept of the Product Lifecycle. Choose Several Case Research Familiar to you personally. How Does the...

Title: Assess the strengths and weaknesses of the concept of the product lifecycle. Choose some circumstance studies familiar to you. How does the theory in the product lifecycle drive online…...

 Sample Essay

Sample Essay

Topic: Relationship between Teachers' qualification and Students' educational performance in Senior Large Schools in Lagos Point out, Nigeria. Exploration Question: Carry out teachers' certification affect the educational performance of…...

 Shakespeare Creates About Problems that Are Still Relevant Today Article

Shakespeare Creates About Problems that Are Still Relevant Today Article

Shakespeare creates about problems that are still relevant today William shakespeare writes regarding issues that continue to be relevant today because his themes happen to be universal, his…...