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The reaction of sodium peroxide and water produces sodium hydroxide and oxygen gas. The following balanced chemical equation rep

a_sh-v [17]

Answer:

3.925 mol.

Explanation:

From the balanced equation:

It is clear that 2 moles of Na₂O₂ react with 2 moles of H₂O to produce 4 moles of NaOH and 1 mole of O₂ .

<em>Using cross multiplication:</em>

4 moles of NaOH produced with → 1 mole of O₂ .

15.7 moles of NaOH produced with → ??? mole of O₂ .

<em>∴ The no. of moles of O₂ made =</em> (1 mole)(15.7 mole)/(4 mole) = <em>3.925 mol.</em>

8 0

4 years ago

Vinegar contains 5g of acetic in 100mL of solution so the (w/v)% concentration is:

Andreyy89

The (w/v)% concentration of vinegar contains 5g of acetic in 100mL of solution is approx 0.5 %

<h3>What is Concentration ?</h3>

The concentration of a chemical substance expresses the amount of a substance present in a mixture.

There are many different ways to express concentration.(w/v)% is one of them.

Given ;

Mass of solute(acetic acid) is 5.0 g
Volume of solution is 100.0 mL.

We need to convert the grams of acetic acid to moles ;

Formula of acetic acid is CH₃COOH

Thus,

Molar mass of acetic acid = 2(12.01) + 4(1.01) + 2(16)

= 24.02 + 4.04 + 32

= 60.06 grams per mol

Moles of acetic acid = 5.0/60.06

= 0.083 moles

(w/v)% = 0.083 x 60 / 1000 x 100

= 0.498 %

= 0.5 %

Hence, The (w/v)% concentration of vinegar contains 5g of acetic in 100mL of solution is approx 0.5 %

Learn more about weight percentage here ;

brainly.com/question/22575652

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8 0

2 years ago

At 298 K, what is the Gibbs free energy change (ΔG) for the following reaction?

9966 [12]

Answer:

(a). The Gibbs free energy change is 2.895 kJ and its positive.

(b). The Gibbs free energy change is 34.59 J/mole

(c). The pressure is 14924 atm.

(d). The Gibbs free energy of diamond relative to graphite is 4912 J.

Explanation:

Given that,

Temperature = 298 K

Suppose, density of graphite is 2.25 g/cm³ and density of diamond is 3.51 g/cm³.

$\Delta H\ for\ diamond = 1.897 kJ/mol$

$\Delta H\ for\ graphite = 0 kJ/mol$

$\Delta S\ for\ diamond = 2.38 J/(K mol)$

$\Delta S\ for\ graphite = 5.73 J/(K mol)$

(a) We need to calculate the value of $\Delta G$ for diamond

Using formula of Gibbs free energy change

$\Delta G=\Delta H-T\Delta S$

Put the value into the formula

$\Delta G= (1897-0)-298\times(2.38-5.73)$

$\Delta G=2895.3$

$\Delta G=2.895\ kJ$

The Gibbs free energy change is positive.

(b). When it is compressed isothermally from 1 atm to 1000 atm

We need to calculate the change of Gibbs free energy of diamond

Using formula of gibbs free energy

$\Delta S=V\times\Delta P$

$\Delta S=\dfrac{m}{\rho}\times\Delta P$

Put the value into the formula

$\Delta S=\dfrac{12\times10^{-6}}{3.51}\times999\times10130$

$\Delta S=34.59\ J/mole$

(c). Assuming that graphite and diamond are incompressible

We need to calculate the pressure

Using formula of Gibbs free energy

$\beta= \Delta G_{g}+\Delta G+\Delta G_{d}$

$\beta=V(-\Delta P_{g})+\Delta G+V\Delta P_{d}$

$\beta=\Delta P(V_{d}-V_{g})+\Delta G$

Put the value into the formula

$0=\Delta P(\dfrac{12\times10^{-6}}{3.51}-\dfrac{12\times10^{-6}}{2.25})\times10130+2895.3$

$0=-0.0194\Delta P+2895.3$

$\Delta P=\dfrac{2895.3}{0.0194}$

$\Delta P=14924\ atm$

(d). Here, $C_{p}=0$

So, The value of $\Delta H$ and $\Delta S$ at 900 k will be equal at 298 K

We need to calculate the Gibbs free energy of diamond relative to graphite

Using formula of Gibbs free energy

$\Delta G=\Delta H-T\Delta S$

Put the value into the formula

$\Delta G=(1897-0)-900\times(2.38-5.73)$

$\Delta G=4912\ J$

Hence, (a). The Gibbs free energy change is 2.895 kJ and its positive.

(b). The Gibbs free energy change is 34.59 J/mole

(c). The pressure is 14924 atm.

(d). The Gibbs free energy of diamond relative to graphite is 4912 J.

7 0

3 years ago

Which of the following is not an example of predation?

swat32

Answer:

the flower big pollinated by The Bee and the receiving letter from the flower

8 0

3 years ago

A red shift in the spectrum of the light from an object indicates the object is moving ____ you.

jek_recluse [69]

Away from you. This is known as the Doppler affect. It basically states that if an object is moving away from you the streching of the wave causes a red shift and if the object is moving towards you the compression of the waves causes a blue shift.

3 0

3 years ago