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3 years ago

Chemical properties of potassium

1 answer:

6 0

Atomic number19
Atomic mass39.0983g.mol -1
Electronegativity according to Pauling0.8
Density0.86
g.cm -3 at 0 °C
Melting point 63.2 °C

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Boron has two isotopes, Boron 10 which has a mass of 10.0129 amu and Boron-11 with a mass of 11.0093 amu. B-10 occurs 84.74% of

podryga [215]

The average atomic mass of Boron: 10.431 amu

<h3>Further explanation </h3>

Isotopes are atoms whose no-atom has the same number of protons while still having a different number of neutrons.

So Isotopes are elements that have the same Atomic Number (Proton)

Atomic mass is the average atomic mass of all its isotopes

In determining the mass of an atom, as a standard is the mass of 1 carbon-12 atom whose mass is 12 amu

Mass atom X = mass isotope 1 . % + mass isotope 2.% + ...

The average atomic mass of boron :

$\tt avg~mass=0.8474\times 10.0129+0.1526\times 11.0093\\\\avg~mass=10.431~amu$

3 0

3 years ago

An equimolar mixture of acetone and ethanol is fed to an evacuated vessel and allowedto come to equilibrium at 65°C and 1.00 atm

frutty [35]

The question is incomplete, the table of the question is given below

Answer:

I) xA= 0.34, yA= 0.55

ii) 76.2 mole % vapor

iii) Percentage of vapor volume = 98%

Explanation:

i) xA= 0.34, yA= 0.55

xA= 0.34, yA= 0.55

ii) 0.50 = 0.55 nv + 0.34 nL

Therefore, nV = 0.762 mol vapor and nL = 0.238 mol liquid

This shows 76.2 mole % vapor

iii) ρA= 0.791 g/cm3 and, ρE = 0.789 g/cm3

Therefore, ρ = 0.790 g/cm3

Now, we have:

MA = 58.08 g/mol and ME= 46.07 g/mol

So Ml = (0.34 x 58.08)+[(1 -0.34) x 46.07] = 50.15 g/mol

1 mol liquid = (0.762 mol vapor/0.238 mol liquid) = 3.2 mol vapor

Liquid volume = Vl= [1 mol x (50.15 g/mol)] / (0.790 g/cm3) = 63.48 cm3

Vapour volume = Vv = 3.2 mol x(22400 cm3/mol) x [(65+273)/273] = 88747 cm3

Therefore, percentage of vapour volume = 88747 / (88747+63.48) = 99.9 %

3 0

3 years ago

The physical world around us behaves as it does partly because it’s made of a huge number of tiny molecules, each behaving rando

eduard

1. Weird things like the one described above do not happen on a ramdom basis becuause molecules usually move within any enclosure in a ramdom manner. Thus, it is not possible for some types of particles to aggregate in one point while other types of molecule aggreagate in another point. Based on the kinetic energy that is available for each particle, each particle will move random
through the available space, colliding with one another and with the wall of container.

2. It will be a difficult thing to live in a Maxwell' demon world because, things will happen unpredictably and one will never know what to expect next because anything can happen at anytime. For instance, if one is drinking a glass of water, some of the particles of the water may just decide to aggregate to one part of the cup and start boiling. So, for someone who is taking a glass of water, the water may start boiling right inside his mouth when he is drinking, that will be a bad experience. When one is driving a car, the petrol particles may just decide to freeze up when one is busy speeding on the highway; that can cause a very serious accident. Thus, a world where the Maxwell law operates will be a chaotic world.

3 0

3 years ago

FREE PONITS COME GET YOUR PONITS!!!! :)

trasher [3.6K]

Explanation:

Need points thanks.

7 0

3 years ago

Read 2 more answers

Which of the following is true regarding the law of conservation of mass

Luda [366]

These are the answer options of this question and the comments about their validity:

A) It dictates that the number of molecules on each side of a chemical equation must be the same.

False: the number of molecules can change. Take this simple reaction for example:

2H2(g) + O2 -> 2H2O

You start with 3 molecules, 2 molecules of H2 and 1 molecule of O2, and end with 2 molecules of water. Then the number of molecules of each side is different.

B) It dictates that the number of atoms of each element must be the same on both sides of a chemical equation.

TRUE: in a chemical reaction the atoms remain being the same at start and at the end of the process. Given that each atom has a characteristic mass, their conservation implies the law of conservation mass.

C) It states that the mass of the reactants must remain constant in order for a chemical reaction to proceed.

FALSE. The mass of the reactants changes during a chemical reaction, while they transform into the products.

D) It does not apply to chemical reactions.

FALSE: It is an important law used in the calculus related with chemical reactions.

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3 years ago