How is a gas formed?

What is the pOH of 0.50 molar H3BO3?

Crazy boy [7]

Answer:

A. 10.25

Explanation:

Pkb =4.77

So pka = 14 - pka = 9.23

$Ka =10^{-pka}$

$H_3 BO_3 (aq)+ H_2 O(l) H_2 BO_3^- (aq)+H_3 O^+ (aq)$

Initial 0.50M 0 0

Change -x +x +x

Equilibrium 0.50M-x +x +x

$Ka =\frac {((x)(x))}{(0.50M-x)}$

$5.88\times10^{-10}= \frac {x^2}{(0.50M-x)}$

(-x is neglected) so we get

$5.88\times10^{-10}\times0.50=x^2\\\\x^2=2.94\times10^{-10}$

$x=\sqrt{x^2}=1.72\times10^{-5} M=H^3 O^{+}$

$pH=-log[H^3 O^+]\\\\pH=-log[1.72\times10^{-5}]\\\\pH=4.76$

pOH = 14 - pH

= 14 - 4.76

pOH = 9.24 is the answer

Option A - 10.25 is the answer which is close to 9.24

4 0

3 years ago

Briefly describe bohr's model postulates and its limitations.

ch4aika [34]

Answer:

Bohr's Model postulates-

I postulate - The electrons in an atom orbit around the nucleus in definite circular paths called orbits or shells.

II Postulate - Each shell or orbit represents a specific amount of energy.

III Postulate - By emitting or absorbing energy, an electron may shift from one stationary energy orbit to another.

Three main Limitations -

1- It adjusts to the hydrogen atom's spectrum but not to the spectra of other atoms.

2 - In the definition of the electron as a tiny particle that spins around the atomic nucleus, the wave properties of the electron are not described.

3- Bohr is unable to understand why classical electromagnetism is inapplicable to his model. That is why, when electrons are in a stationary orbit, they do not emit electromagnetic radiation.

Explanation:

About Bohr's postulates-

1 - The electron spins in circling circles around the nucleus, emitting no energy. The orbital angular momentum is constant in these orbits.

Only certain radii of orbits, corresponding to certain given energy levels, are required for electrons in an atom.

2- Not every orbit is possible. However, whenever an electron is in a legal orbit, it is in a state of unique and constant energy and does not emit energy (stationary energy orbit).

For example - The energies allowed for electrons in the hydrogen atom are given by the following equation: The Rydberg constant for the hydrogen atom is $-2.8\times10^-^1^8$ in this equation, and n = quantum number will range from 1 to ∞. For each of the values of n, the electron energies of a hydrogen atom produced by the above equation are negative. As n rises, the energy becomes less negative and thus rises.

3- By emitting or absorbing energy, an electron may shift from one stationary energy orbit to another.

The energy difference between the two states would be equal to the energy released or consumed. This energy E is in the form of a photon, and it can be measured using the following formula:

$E=h$ $v$

E is the energy (absorbed or emitted) in this equation, and h is the Planck constant (its value is $6.63\times10^-^3^4 Js$ ) and v denotes the frequency of light, which is calculated in 1/ s.

8 0

3 years ago

In a molecule of chlorine (Cl2), the chlorine atoms are connected to each other by a single bond. Which statements correctly des

blsea [12.9K]

Answer:

It is a sigma bond

Explanation:

Chlorine has an electronic configuration of 1s2 2s2 2p6 3s2 3p5. This means that the outermost n=3 level has seven electrons. Hence one more electron is needed for the octet of outermost electrons to be achieved. As a result of this, chlorine enters into covalent bonding with another chlorine atom to form Cl2.

The outermost 3p electrons of the two chlorine atoms are now shared to form a p-p sigma bond (a single bond). Hence, the Cl2 molecule contains a sigma(single) bond between two chlorine atoms. Hence the answer written above.

7 0

4 years ago

The trait for flower color in a plant has red and white alleles. The red color is the dominant trait. What is the phenotypic rat

Fudgin [204]

Answer :

2 red : 2 white

Explanation:

;)long story short

hetro with hetro gives 3:1
hetro with recessive gives 1:1

Hetro :- ( Rr) one capital letter and one small
Recessive :- (rr) two small leters

6 0

3 years ago

Which would be the best to neutralize a large acid spill in your school lab: sodium hydroxide or baking soda? Explain.

nadya68 [22]

Consider the acid spill. It is already starting to do nasty things to, say, the floor or counter. So you grab the bottle of 10% NaOH and pour some on the spill. All of a sudden, you get a great deal of heat, and you don't have any visual evidence whether your put on too little or too much. But you have added more liquid to the spill, generated more heat, and will get more damage. You have made a bigger mess, and if you added too much, you then have a neutralization problem to deal with.

And if it is something like a strong sulfuric acid solution, adding sodium hydroxide solution will be extremely exothermic, and you could get some really nasty results.

So now approach the spill with a handful of baking soda. You sprinkle it on the spill. It fizzes, and carbon dioxide is given off. That actually, in a very tiny way, moderates the temperature of the neutralization. And you can keep adding baking soda until the fizzing stops, and then perhaps some water to mix everything well. But what you have done is kept the volume to a minimum, added a neutralization agent that has a visible endpoint (no more gas being given off), and you don't suddenly have a huge amount of highly basic solution because you added too much.

And what is also nice about baking soda is that you can toss some with your hand or even with a spoon, and get some distance from the spill. With a liquid, you have to get much closer

i hope this helped..

5 0

3 years ago