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The contents of a Helium ballon are in which phase? A. Solid B. Plasma C. Liquid G. Gas

cluponka [151]

Helium is stable compound. exists in gaseous state. the answer is gas

6 0

4 years ago

What is the length of a one-dimensional box for an electron (9.109 x 10-31 kg) with an n=1 energy of 479 kJ/mol? Give the answer

OverLord2011 [107]

Answer : The length of a one-dimensional box for an electron is $2.819\times 10^{31}\AA$

Explanation :

The energy level of quantum particle in a one-dimensional box is given as:

$E_n=\frac{n^2h^2}{8mL^2}$

where,

$E_n$ = 479 kJ/mol = 479000 J/mol

n = energy level = 1

h = Planck's constant = $6.626\times 10^{-34}Js$

m = mass of electron = $9.109\times 10^{-31}kg$

L = length of a one-dimensional box = ?

Now put all the given values in the above formula, we get:

$479000J/mol=\frac{(1)^2\times (6.626\times 10^{-34}Js)^2}{8\times (9.109\times 10^{-31}kg)\times L^2}$

$L=2.819\times 10^{21}m$

conversion used : $1m=10^{10}\AA$

$L=2.819\times 10^{31}\AA$

Therefore, the length of a one-dimensional box for an electron is $2.819\times 10^{31}\AA$

3 0

3 years ago

Select the correct answer from the drop-down menu. a scientist digs up sample of arctic ice that is 458,000 years old. he takes

Jlenok [28]

The original mass of krypton 81 that is present in the ice is 6.70 grams.

<h3>How do we calculate original mass?</h3>

Original mass of any substance will be calculated as below for the decomposition reaction is:

N = N₀(1/2)ⁿ, where

N = remaining mass of krypton-81 = 1.675g

N₀ = original mass of krypton-81 = ?

n will be calculated as:
n = T/t, where

T = total time period = 458,000 years

t = half life time = 229,000 years

n = 458,000/229,000 = 2

Now putting all these values on the above equation, we get

N₀ = 1.675 / (1/2)²

N₀ = 6.70 g

Hence required mass is 6.70 g.

To know more about half life time, visit the below link:
brainly.com/question/2320811

8 0

3 years ago

Complete the dissociation reaction and the corresponding Ka equilibrium expression for each of the following acids in water. (Ty

anastassius [24]

Answer :

(A) The dissociation reaction of $HC_2H_3O_2$ will be:

$HC_2H_3O_2(aq)\rightleftharpoons H^+(aq)+C_2H_3O_2^-(aq)$

The equilibrium expression :

$K_a=\frac{[H^+][C_2H_3O_2^-]}{[HC_2H_3O_2]}$

(B) The dissociation reaction of $Co(H_2O)_6^{3+}$ will be:

$Co(H_2O)_6^{3+}(aq)\rightleftharpoons H^+(aq)+Co(H_2O)_5(OH)^{2+}(aq)$

The equilibrium expression :

$K_a=\frac{[H^+][Co(H_2O)_5(OH)^{2+}]}{[Co(H_2O)_6^{3+}]}$

(C) The dissociation reaction of $CH_3NH_3^+$ will be:

$CH_3NH_3^+(aq)\rightleftharpoons H^+(aq)+CH_3NH_2(aq)$

The equilibrium expression :

$K_a=\frac{[H^+][CH_3NH_2]}{[CH_3NH_3^+]}$

Explanation :

Equilibrium constant : It is defined as the equilibrium constant. It is defined as the ratio of concentration of products to the concentration of reactants.

The equilibrium expression for the reaction is determined by multiplying the concentrations of products and divided by the concentrations of the reactants and each concentration is raised to the power that is equal to the coefficient in the balanced reaction.

As we know that the concentrations of pure solids and liquids are constant that is they do not change. Thus, they are not included in the equilibrium expression.

(A) The dissociation reaction of $HC_2H_3O_2$ will be:

$HC_2H_3O_2(aq)\rightleftharpoons H^+(aq)+C_2H_3O_2^-(aq)$

The equilibrium expression of $HC_2H_3O_2$ will be:

$K_a=\frac{[H^+][C_2H_3O_2^-]}{[HC_2H_3O_2]}$

(B) The dissociation reaction of $Co(H_2O)_6^{3+}$ will be:

$Co(H_2O)_6^{3+}(aq)\rightleftharpoons H^+(aq)+Co(H_2O)_5(OH)^{2+}(aq)$

The equilibrium expression of $Co(H_2O)_6^{3+}$ will be:

$K_a=\frac{[H^+][Co(H_2O)_5(OH)^{2+}]}{[Co(H_2O)_6^{3+}]}$

(C) The dissociation reaction of $CH_3NH_3^+$ will be:

$CH_3NH_3^+(aq)\rightleftharpoons H^+(aq)+CH_3NH_2(aq)$

The equilibrium expression of $CH_3NH_3^+$ will be:

$K_a=\frac{[H^+][CH_3NH_2]}{[CH_3NH_3^+]}$

3 0

3 years ago

Why is a Container important to the sustainability of your hydroponic system?

sergij07 [2.7K]

Hydroponics is more than just another way to grow plants–the technology has the potential to change how we engage with food cultivation as a whole! For the first time since humans started tilling the land, modern hydroponics technology frees us from the soil beneath our feet, allowing us to bring food production indoors where we can layer in additional climate and lighting controls. The result is an ability to grow food anytime, anywhere in the world.

7 0

3 years ago