Which of the following statements is NOT true?

Given: A(g) + B(g) ⇋ C(g) + D(g) At equilibrium a 2.00 liter container was found to contain 1.60 moles of C, 1.60 moles of D, 0.

Alexandra [31]

Answer:

Kc = 10.24

Q = 9.07

[A] = 0.262 mol/L

Explanation:

In a reversible reaction, the equilibrium occurs when the velocity of the formation of the products is equal to the velocity of the formation of the reactants. When this happens, the concentrations remain constant. The ratio between the multiplication of the concentration of the products by the multiplication of the reactants (each concentration elevated by the substance's coefficient) is called Kc, the equilibrium constant.

The value of the Kc depends on the temperature, and the pure liquids and solids are considered to have concentration equal to 1 (because it's activity is equal to 1, and the activity is aproximated to the concentrantion). So, for the reaction given, the concentrations at the equilibrium are:

[A] = 0.50 moles / 2.00 liter = 0.25 mol/L

[B] = 0.50 moles / 2.00 liter = 0.25 mol/L

[C] = 1.60 moles / 2.00 liter = 0.80 mol/L

[D] = 1.60 moles / 2.00 liter = 0.80 mol/L

Kc = [C]*[D]/[A]*[B]

Kc = 0.8*0.8/0.25*0.25

Kc = 0.64/0.0625

Kc = 10.24

The value of Q, the reaction quotient, is calculated as the value of Kc, but now, with the concentrations at a certain time and not necessariy in equilibrium. The new concentrantions of B and C will be:

[B] = (0.50 + 0.10)/2.00 = 0.3 mol/L

[C] = (1.60 + 0.10)/2.00 = 0.85 mol/L

Q = [C]*[D]/[A]*[B]

Q = 0.85*0.8/0.25*0.3

Q = 0.68/0.075

Q = 9.07

Because more product was added, by the Le Chatelier's principle, the reaction will shift in order to consume C and D, and forms more A and B, and so the equilibrium will be achieved again, so, let's do an equilibrium chart:

A(g) + B(g) ⇄ C(g) + D(g)

0.25 0.3 0.85 0.8 Initial

+x +x -x -x Reacts (stoichiometry is 1:1:1:1)

0.25+x 0.3+x 0.85-x 0.8-x Equilibrium

Kc = (0.85-x)*(0.8-x)/(0.25+x)*(0.3+x)

10.24 = (0.68 - 1.65x + x²)/(0.075 + 0.55x + x²)

10.24x² + 5.632x + 0.768 = 0.68 - 1.65x + x²

9.24x² + 7.282x - 0.088 = 0

Solving by a graphic calculator, and knowing that x > 0 and x < 0.8

x = 0.012 mol/L

So, [A] = 0.25 + 0.012 = 0.262 mol/L

6 0

3 years ago

The South Pole has warm summers. True False

agasfer [191]

Answer:False

Explanation:

Kinda of a opinionated question, but unless you call -12 C warm then the answer is False

7 0

3 years ago

What volume did a helium-filled balloon have at 22.5 c and 1.95 atm if it’s new volume was 56.4 mL at 3.69 atm and 11.9c

Veseljchak [2.6K]

This is an exercise in the general or combined gas law.

To start solving this exercise, we obtain the following data:

T₁ = 22.5 °C + 273 = 295.5 K
P₁ = 1.95 atm
V₁ = ¿?
P₂ = 3.69 atm
T₂ = 11.9 °C + 273 = 284.9 k
V₂= 56.4 ml

We use the following formula:

P₁V₁T₂ = P₂V₂T₁ ⇒ General formula

Where

P₁ = Initial pressure
V₁ = Initial volume
T₂ = Initial temperature
P₂ = Final pressure
V₂ = final volume
T₁ = Initial temperature

We clear the formula for the initial volume:

$\boldsymbol{\sf{V_{1}=\dfrac{P_{2}V_{2}T_{1}}{P_{1}T_{2}} } }$

We substitute our data into the formula to solve:

$\boldsymbol{\sf{V_{1}=\dfrac{(3.69 \not{atm})(56.4 \ ml)(295.5 \not{k})}{(1.95 \not{atm})(284.9\not{k})} }}$

$\boldsymbol{\sf{V_{1}=\dfrac{61498.278}{555.555} \ lm }}$

$\boxed{\boldsymbol{\sf{V_{1}=110.697 \ lm }}}$

The helium-filled balloon has a volume of <u>110.697 ml.</u>

6 0

1 year ago

Read 2 more answers

PLEASEEEE HELPPPPP ASAP!!!!!

Wewaii [24]

Answer: Adding a reactant will shift the reaction towards the products.

Adding a product will shift the reaction towards the reactants.

Removing a reactant will shift the reaction towards the reactants.

Removing a product will shift the reaction towards the products.

Explanation:

Any change in the equilibrium is studied on the basis of Le-Chatelier's principle.This principle states that if there is any change in the variables of the reaction, the equilibrium will shift in the direction to minimize the effect.

Adding a reactant will increase the concentration of reactants and hence the reaction will try to undo the increase by shifting the reaction towards the products.

Adding a product will increase the concentration of products and hence the reaction will try to undo the increase by shifting the reaction towards the reactants.

Removing a reactant will decrease the concentration of reactants and hence the reaction will try to undo the decrease by shifting the reaction towards the reactants.

Removing a product will decrease the concentration of products and hence the reaction will try to undo the decrease by shifting the reaction towards the products.

8 0

2 years ago

Read 2 more answers

Molybdenum metal requires a photon with a minimum frequency of 1.09x1015s-1before it can emit an electron via the photoelectric

11Alexandr11 [23.1K]

Answer:

a) 7.22 × 10⁻¹⁹ J; b) 275 nm; c) 1.38× 10¹² electrons; d) 9.1 × 10⁻¹⁹ J

Explanation:

a) Minimum energy to eject photon

E = hf = 6.626× 10⁻³⁴ J·s × 1.09 × 10¹⁵ s⁻¹ = 7.22 × 10⁻¹⁹ J

b) Wavelength required

fλ = c

$\lambda = \dfrac{c}{f } = \dfrac{2.998 \times 10^{8}\text{ m/s}}{1.09 \times 10^{15}\text{/s}} = 2.75 \times 10^{-7} \text{ m} = \textbf{275 nm}$

c) Electrons required

$\text{No. of electrons} = 1.00 \times 10^{-6}\text{ J} \times \dfrac{\text{1 electron}}{7.22 \times 10^{-19}\text{ J}} = 1.38 \times 10^{12}\text{ electrons}$

d) Kinetic energy of electrons

a) Energy of photon

$E = hf = \dfrac{\text{hc}}{\lambda} = \dfrac{6.626 \times 10^{-34} \text{ J$\cdot$ s}\times 2.998 \times 10^{8} \text{ m/s}}{122 \times 10^{-9}\text{ m}}= 1.63 \times 10^{-18} \text{ J}$

b) Maximum kinetic energy

The equation for the photoelectric effect is

hf = φ + KE, where

φ = the work function of the metal — the minimum energy needed to eject an electron

KE = hf - φ = 1.63× 10⁻¹⁸ J - 7.22× 10⁻¹⁹ J = 9.1 × 10⁻¹⁹ J

4 0

3 years ago