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3 years ago

Given the standard entropy values in the table, what is the value of `Delta"Sº"_"reaction"` for the following reaction?

Chemistry

2 answers:

Verizon [17]3 years ago

8 0

Answer:

$\Delta S^o=-149\frac{J}{mol*K}$

Explanation:

Hello,

In this case, we define the standard change in the entropy for a chemical reaction as:

$\Delta S^o=\Sigma \nu _iS_i^o$

Whereas $\nu _i$ is the stoichiometric coefficient of the species i which is negative for products and positive for reactants and $S_i^o$ is the standard entropy for the species i in J/mol*K. Thus, we have:

$\Delta S^o=(-2)(53} )+(-3)(205)+(2)(248)+(2)(38)\\\Delta S^o=-149\frac{J}{mol*K}$

Best regards.

Fantom [35]3 years ago

4 0

Answer:

entropy of reaction = 572-718= -146J/mol-k.

Explanation:

entropy of a reaction = entropy of product - entropy of reactant.

entropy of product = 2×entropy of SO2+2×entropy of NiO

= $2\times 248+2\times 38$

=572 J/mol-k

entropy of reactant = 2×entropy if NiS+3×entropy of O2

= $2\times 53+3\times 205$

=718 J/mol-k

therefore entropy of reaction = 572-718= -146J/mol-k.

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Water contrasts on freezing ?

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You can test this by freezing water in a water bottle: when you take it out of the freezer, the cap might have popped off or cracks may have formed in the sides of the bottle.

Answer: Water expands when frozen, not contracts.

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3 years ago

1. Have scientists been able to invent a perpetual motion machine? O Yes O No

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2 years ago

Read 2 more answers

What is the percent composition by mass of sulfur in the compound mgso4

Margaret [11]

Answer:

26.7% is the percent composition by mass of sulfur in a compound named magnesium sulfate.

Explanation:

Molar mass of compound = 120 g/mol

Number of sulfur atom = 1

Atomic mass of sulfur = 32 g/mol

Percentage of element in compound :

$=\frac{\text{Number of atoms}\times \text{Atomic mass}}{\text{molar mas of compound}}\times 100$

Sulfur :

$=\frac{1\times 32 g/mol}{120 g/mol}\times 100=26.7\%$

26.7% is the percent composition by mass of sulfur in a compound named magnesium sulfate.

6 0

3 years ago

If an element has 2+ valence electrons, does it transfer only one or more than one valence electrons

just olya [345]

Answer:

element having 2+ valence electrons can transfer its more than one electron that is 2 electron completely.

Explanation:

Group IIA have 2+ valency and two electrons in its valance shell.

Its Electropositivity is high and have the tendency to donate it two electrons.

Element of IIA form ionic with most electronegative element.

Examples:

Cu²⁺, Mg²⁺, Sr²⁺ are examples having 2+ valance electron

one of the following is examples of element that have 2+ valence electrons

MgCl₂

Atomic number of Magnesium (Mg) is 12

Electronic Configuration of Mg:

1s², 2s², 2p⁶, 3s²

K =2

L = 8

M = 2

So, it have to give its 2 electrons to form a stable compound.

Similarly

Chlorine atomic number is 17

Electronic Configuration of Chlorine:

1s², 2s², 2p⁶, 3s², 3p⁵

K =2

L = 8

M = 7

So, it have to gain one electrons to form a stable compound and complete its octet.

So,

Two chlorine atom as a molecule gain 2 electrons from Mg²⁺ atom

So one Mg²⁺ and 2 Cl⁻ atoms form an ionic bond

where in this ionic bond Mg²⁺ transfer its 2 valence electron completely and chlorine molecule accept 2 electrons.

Cl-----Mg------Cl

So the Answer is

element having 2+ valence electrons can transfer its more than one electron that is 2 electron completely.

8 0

3 years ago

Pharmacists sometimes measure medicines in the unit of "grains," where 1 gr = 65 mg. The label on a bottle of aspirin reads "Asp

viva [34]

Answer:

325mg of Aspririn

Explanation:

First you should note the information that the problem gives you:

- The bottle of Aspirin has 5gr (grains)

- 1gr(grain) = 65mg (miligrams)

Also, the problem is asking about how many aspirin are in 5 gr (grains), so you should use a conversion factor, as follows:

-First you should put the quantity you need to convert:

$5grAspirin$

-Then you write the denominator of the conversion factor that must have the same units that you want to convert, in this case gr:

$5grAspirin*\frac{}{1grAspirin}$

-Then you write the numerator with the units that you want to obtain and the numerical equivalence between the units, in this case:

$5grAspirin*\frac{65mgAspririn}{1grAspirin}$

-Finally you multiply numerators and divide by denominators:

$5grAspirin*\frac{65mgAspririn}{1grAspirin}=325mgAspririn$

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3 years ago