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2 years ago

Brainliest! a. Write a short historical account of the discovery of the Avogadro’s number.

Chemistry

1 answer:

kvv77 [185]2 years ago

4 0

Answer:

a. Amadeo Avogadro (1776-1856) was the author of Avogadro's Hypothesis in 1811, which, together with Gay-Lussac's Law of Combining Volumes, was used by Stanislao Cannizzaro to elegantly remove all doubt about the establishment of the atomic weight scale at the Karlsruhe Conference of 1860. The name "Avogadro's Number" is just an honorary name attached to the calculated value of the number of atoms, molecules, etc. in a gram mole of any chemical substance. Of course if we used some other mass unit for the mole such as "pound mole", the "number" would be different than 6.022 x 1023.

b. The first person to have calculated the number of molecules in any mass of substance was Josef Loschmidt, (1821-1895), an Austrian high school teacher, who in 1865, using the new Kinetic Molecular Theory (KMT) calculated the number of molecules in one cubic centimeter of gaseous substance under ordinary conditions of temperature of pressure, to be somewhere around 2.6 x 1019 molecules. This is usually known as "Loschmidt's Constant.

Task 2

Percent composition is the percent by mass of each element present in a compound. Water, H2O, is the first example. One mole of water is 18.0152 grams. In that compound, there are two moles of H atoms and 2 x 1.008 = 2.016 grams. That's how many grams of hydrogen are present in one mole of water. this is an example. i don't know what you are describing though. i need more info for this question

b. 6.022 to 6.023 x 10^23

c. i don't know what this one is since there is nothing to describe the unknown liquid.

d. Yes a killer, but not a specific person

Explanation:

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2 years ago

How are half life and radioactive decay related

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Answer : Half life and radioactive decay are inversely proportional to each other.

Explanation :

The mathematic relationship between the half-life and radioactive decay :

$N=N_oe^{-\lambda t}$ ................(1)

where,

N = number of radioactive atoms at time, t

$N_o$ = number of radioactive atoms at the beginning when time is zero

e = Euler's constant = 2.17828

t = time

$\lambda$ = decay rate

when $t=t_{1/2}$ then the number of radioactive decay become half of the initial decay atom i.e $N=\frac{N_o}{2}$ .

Now substituting these conditions in above equation (1), we get

$\frac{N_o}{2}=N_oe^{-\lambda t_{1/2}}$

By rearranging the terms, we get

$\frac{1}{2}=e^{-\lambda t_{1/2}}$

Now taking natural log on both side,

$ln(\frac{1}{2})=-\lambda \times t_{1/2}$

By rearranging the terms, we get

$t_{1/2}=\frac{0.693}{\lambda}$

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3 years ago

Which of the following can be mixed in solution with NH3 to make a buffer?A. NH4CIB. NaClC. HNO3D. NaOH

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<h2>Answer:</h2>

A.NH4Cl

<h2>Explanations:</h2><h2>How are buffer formed?</h2>

Buffers are formed by mixing an equal amount of weak base or acids and their corresponding salts.

Therefore in order to make a buffer with NH3 (a weak base), then a corresposding weak salt is required. A corresponding salt for the given base is NH4Cl

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