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3 years ago

How many moles are in 2.31*10^21 atoms of lead

1 answer:

6 0

Hey there!:

Molar mass Lead ( Pb ) = 207.2 g/mol

Therefore:

1 mole Pb --------------------- 6.02*10²³ atoms
? moles Pb -------------------- 2.31*10²¹ atoms

moles Pb = ( 2.31*10²¹ ) * 1 / ( 6.02*10²³ ) =

moles Pb = ( 2.31*10²¹ ) / ( 6.02*10²³ ) =

=> 0.00383 moles of Pb

Hope this helps !

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How is conductivity related to pH?

timama [110]

Answer:

Strongly acidic [or strongly basic] solution will have high conductivity.

Explanation:

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3 years ago

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Describe the relationship between volume and temperature of an ideal gas

kvv77 [185]

Answer:

Explanation:

Here, we want to describe the relationship between the volume and temperature of an ideal gas

This relationship is defined by Charles' law

From this law, we know that the volume of a given mass of gas is directly proportional to its temperature at a fixed pressure

What this means is that as long as the pressure remains unchanged, when the volume increases, the temperature increases, and when the volume decreases, the temperature decreases

These can be represented by the mathematical formula below:

$\frac{V_1}{T_1}\text{ = }\frac{V_2}{T_2}$

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1 year ago

Phenolphthalein has a pKa of 9.7 and is colorless in its acid form and pink in its basic form. calculate [In-}/{HIn} for the fol

zvonat [6]

Answer:

1.58x10⁻⁵

2.51x10⁻⁸

0.0126

63.10

Explanation:

Phenolphthalein acts like a weak acid, so in aqueous solution, it has an acid form HIn, and the conjugate base In-, and the pH of it can be calculated by the Handerson-Halsebach equation:

pH = pKa + log[In-]/[HIn]

pKa = -logKa, and Ka is the equilibrium constant of the dissociation of the acid. [X] is the concentrantion of X. Thus,

i) pH = 4.9

4.9 = 9.7 + log[In-]/[HIn]

log[In-]/[HIn] = - 4.8

[In-]/[HIn] = $10^{-4.8}$

[In-]/[HIn] = 1.58x10⁻⁵

ii) pH = 2.1

2.1 = 9.7 + log[In-]/[HIn]

log[In-]/[HIn] = -7.6

[In-]/[HIn] = $10^{-7.6}$

[In-]/[HIn] = 2.51x10⁻⁸

iii) pH = 7.8

7.8 = 9.7 + log[In-]/[HIn]

log[In-]/[HIn] = -1.9

[In-]/[HIn] = $10^{-1.9}$

[In-]/[HIn] = 0.0126

iv) pH = 11.5

11.5 = 9.7 + log[In-]/[HIn]

log[In-]/[HIn] = 1.8

[In-]/[HIn] = $10^{1.8}$

[In-]/[HIn] = 63.10

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3 years ago

1. What is the relation between distance and speed?

Inga [223]

Answer:

option no b is right answer

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3 years ago

Make a prediction about the relationship between electrons and molecular shapes

Oksana_A [137]

Answer:

★ Molecular geometry is described by VSEPR theory, which basically states that electron pairs around a central atom will repel each other, and get as far apart as possible, in three dimensions.

Explanation:

Hope you have a great day :)

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3 years ago