Calculate the number of molecules in 64.5 grams of Nitrogen monoxide, NO

The value of ka for weak acid is to 4.0x10^-5 what is degree of dissociation of the acid in aqueous solution of concentration 0.

lakkis [162]

p

K

a

=

5.4

pH

=

3.7

Explanation:

p

K

a

is simply

−

log

10

(

K

a

)

. It is a constant at any temperature and does not depend on the molarity of the solution.

p

K

a

=

−

log

10

(

K

a

)

=

−

log

10

(

4.0

×

10

−

6

)

=

5.4Explanation:

3 0

3 years ago

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Calculate the Equilibrium constant Kc at 25 C from the free - energy change for the following reaction . Zn(s) + 2Ag+(aq)<---

FinnZ [79.3K]

Answer: $Kc=1.24*10^5^2$

Explanation: For the given reaction:

$Kc=\frac{[Zn^+^2]}{[Ag^+]^2}$

Concentrations of the ions are not given so we need to think about another way to calculate Kc.

We can calculate the free energy change using the standard cell potential as:

$\Delta G^0=-nFE^0_c_e_l_l$

$E^0_c_e_l_l$ can be calculated using standard reduction potentials.

Standard reduction potential for zinc is -0.76 V and for silver, it is +0.78 V.

$E^0_c_e_l_l$ = $E^0_c_a_t_h_o_d_e+E^0_a_n_o_d_e$

Reduction takes place at anode and oxidation at cathode. As silver is reduced, it is cathode. Zinc is oxidized and so it is anode.

$E^0_c_e_l_l$ = 0.78 V - (-0.76 V)

$E^0_c_e_l_l$ = 0.78 V + 0.76 V

$E^0_c_e_l_l$ = 1.54 V

Value of n is two as two moles of electrons are transferred in the cell reaction F is Faraday constant and its value is 96485 C/mol of electron .

$\Delta G^0=-(2*96485*1.54)$

$\Delta G^0$ = -297173.8 J

Now we can calculate Kc using the formula:

$\Delta G^0=-RTlnKc$

T = 25+273 = 298 K

R = $8.314JK^-^1mol^-^1$

--297173.8 = -(8.314*298)lnKc

297173.8 = 2477.572*lnKc

$lnKc=\frac{297173.8}{2477.572}$

lnKc = 119.946

$Kc=e^1^1^9^.^9^4^6$

$Kc=1.24*10^5^2$

5 0

3 years ago

4.50 g of a certain Compound X, known to be made of carbon, hydrogen and perhaps oxygen, and to have a molecular molar mass of 1

Anna11 [10]

Answer:

$\mathbf{C_{10}H_8}$ ( Naphthalene )

Explanation:

Given that:

4.50 g of a Compound X is made up of Carbon , Hydron and Oxygen

It's molecular molar mass = 128 g/mol

Compound X undergoes combustion reaction and the product yield :

CO_2 with mass 15.47g and :

H_2O with mass 2.53 g

The objective is to use this information to determine the molecular formula of X.

We all know that ; number of moles = mass/molar mass

where the molar mass of H_2O is 18 g/mol

number of moles of H_2O product = 2.53 g/18 g/mol

number of moles of H_2O product = 0.1406 moles

Also; the molar mass of CO_2 product = 44 g/mol

number of moles of CO_2 product = 15.47g/ 44 g/mol

number of moles of CO_2 product = 0.3516 moles

number of moles of Compound X in the reactant side= 4.50 g /128 g/mol

number of moles of Compound X n the reactant side= 0.03516 moles

Now; number number of moles of CO_2 in reactant = 0.3516 moles/0.03516 moles

Now; number number of moles of CO_2 in reactant = 10

number of moles of H_2O reactant = 0.1406 moles × 2/0.03516

number of moles of H_2O reactant = 7.997 ≅ 8

Since we said the Compound X is known to be made of Carbon C , Hydrogen H and Oxygen O

Then the molecular formula can be written as :

$\mathbf{C_{10}H_8O_{x}}$

In order to find the x; we have

128 = (12 × 10 + 1 × 8 + 16 × x)

128 = 120 + 8 + 16x)

128 = 128 + 16 x

128 - 128 = 16 x

0 = 16 x

x = 0/16

x = 0

As x = 0 ; hence there are no oxygen present in the reaction

Thus; the molecular formula of Compound X = $\mathbf{C_{10}H_8}$ which is also known as Naphthalene

5 0

3 years ago

If 3.50 moles of sodium chloride is added to your food, how many grams is added?

Ksenya-84 [330]

Answer:

204.8g

Explanation:

The number of moles of a substance is related to its mass and molecular mass as follows:

mole (n) = mass (m) ÷ molar mass (MM)

According to this question, 3.50 moles of sodium chloride (NaCl) is added to a food.

Molar mass of NaCl = 23 + 35.5

= 58.5g/mol

Using mole = mass/molar mass

Mass = molar mass × mole

Mass = 58.5g/mol × 3.5mol

Mass = 204.75

Mass = 204.8grams.

Therefore, 204.8grams of NaCl or common salt was added to the food.

7 0

3 years ago

How does the chemical formula for the sulfite ion differ from the chemical formula for the sulfate ion?

VLD [36.1K]

Answer:

Sulfite contains 3 oxygens and sulfate contains 4 oxygens

Explanation:

6 0

3 years ago