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3 years ago

How many mol of hydrogen in 2.8 mol of caffeine.

2 answers:

5 0

Empirical formula of caffeine is C₈H₁₀N₄O₂.

In 1 mol of caffeine we have 10 mol of hydrogen.
In 2,8 mol of caffeine we have x mol of hydrogen.

x = 2,8 mol * 10 mol / 1 mol = 28 mol

ANSWER: There are 28 mol of hydrogen.

:-) ;-)

Rama09 [41]3 years ago

5 0

Answer:

Empirical formula of caffeine is C₈H₁₀N₄O₂. In 1 mol of caffeine we have 10 mol of hydrogen. In 2,8 mol of caffeine we have x mol of hydrogen. ANSWER: There are 28 mol of hydrogen.

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If 42.8 mL of 0.204 M HCl solution is needed to neutralize a solution of Ca(OH)2, how many grams of Ca(OH)2 must be in the solut

Aneli [31]

Hey There!

At neutralisation moles of H⁺ from HCl = moles of OH⁻ from Ca(OH)2 so :

0.204 * 42.8 / 1000 => 0.0087312 moles

Moles of Ca(OH)2 :

2 HCl + Ca(OH)2 = CaCl2 + 2 H2O

0.0087312 / 2 => 0.0043656 moles ( since each Ca(OH)2 ives 2 OH⁻ ions )

Therefore:

Molar mass Ca(OH)2 = 74.1 g/mol

mass = moles of Ca(OH)2 * molar mass

mass = 0.0043656 * 74.1

mass = 0.32 g of Ca(OH)2

Hope that helps!

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3 years ago

What statement would beast describe a digital signal

Assoli18 [71]

Best* and are there answer choic

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3 years 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

esulfur burns easily .Iron is attracted by magnets .the mineral made by sulfur and iron ,but it does not burn and it is not attr

vladimir2022 [97]

The mineral is Iron Sulphide. It is not a mixture, but a compound. A mixture is when two substances are together, but not chemically bonded. For example, if I add food colouring to water, I have made a mixture because the food colouring has not chemically bonded to the water. If I react Iron with Suphur, the resulting substance is a compound. The resulting mineral will not burn or be magnetic because the compound has different properties to the elements themselves. For example, chlorine gas is toxic and sodium reacts violently with water, but sodium chloride is table salt, nor toxic nor explosive. Hope this helps

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2 years ago

Which elements have electron configurations that end in ns 2 np 5 ? halogens noble gases inner transition metals transition meta

4vir4ik [10]

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3 years ago