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2 years ago

A given sample of caffeine, C8H10N4O2, has 6.47 x 1022

Chemistry

1 answer:

Verdich [7]2 years ago

3 0

Answer:

8.08 × $10^{22}$ atoms of hydrogen

Explanation:

From the given data, we have two categories of variables (unknowns):

Amount (moles or mass) of Caffeine
Amount (moles or mass) of Hydrogen

The longer route would be to solve for these variables first, by determining the number of moles of the Caffeine sample (0.134 moles of C8H10N4O2) from the mass of carbon (12.89 g = 1.07 moles in 6.47 $10^{22}$ atoms) provided. And then solve for the number of atoms of H. [N.B: 1 mole of ANY substance = 6.022 × $10^{22}$ atoms ]

Alternatively and quicker, we can use the mole ratios of the Carbon:Hydrogen atoms in the compound.

8 : 10 ≡ 4 : 5

If 4 moles -- 6.47 $10^{22}$ atoms

Then 5 moles -- ?? atoms

⇒ No. of atoms of Hydrogen = $\frac{5*6.47*10^{22}}{4}$

=8.08 × $10^{22}$ atoms of hydrogen

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Luden [163]

Answer:

The molar mass of the compound is:- 168.82 g/mol

The molar mass of the gas is:- 16.38 g/mol

Explanation:

(a)

Using ideal gas equation as:

$PV=nRT$

where,

P is the pressure

V is the volume

n is the number of moles

T is the temperature

R is Gas constant having value = 0.0821 L.atm/K.mol

Also,

Moles = mass (m) / Molar mass (M)

Density (d) = Mass (m) / Volume (V)

So, the ideal gas equation can be written as:

$PM=dRt$

Given that:-

Pressure = 20 kPa = 20000 Pa

The expression for the conversion of pressure in Pascal to pressure in atm is shown below:

P (Pa) = $\frac {1}{101325}$ P (atm)

20000 Pa = $\frac {20000}{101325}$ atm

Pressure = 0.1974 atm

Temperature = 330 K

d = 1.23 kg/m³ = 1.23 g/L

Molar mass = ?

Applying the equation as:

0.1974 atm × M = 1.23 g/L × 0.0821 L.atm/K.mol × 330 K

⇒M = 168.82 g/mol

The molar mass of the compound is:- 168.82 g/mol

(b)

Given that:

Pressure = 152 Torr

Temperature = 298 K

Volume = 250 cm³ = 0.25 L

Using ideal gas equation as:

$PV=nRT$

R = $62.3637\text{torr}mol^{-1}K^{-1}$

Applying the equation as:

152 Torr × 0.25 L = n × 62.3637 L.torr/K.mol × 298 K

⇒n = 0.002045 moles

Given that :

Mass of the gas = 33.5 mg = 0.0335 g

Molar mass = ?

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$0.002045\ moles
= \frac{0.0335\ g}{Molar\ mass}$

The molar mass of the gas is:- 16.38 g/mol

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2 years ago

Challenge question: This question is worth 6 points. As you saw in problem 9 we can have species bound to a central metal ion. T

GenaCL600 [577]

Answer:

CN^- is a strong field ligand

Explanation:

The complex, hexacyanoferrate II is an Fe^2+ specie. Fe^2+ is a d^6 specie. It may exist as high spin (paramagnetic) or low spin (diamagnetic) depending on the ligand. The energy of the d-orbitals become nondegenerate upon approach of a ligand. The extent of separation of the two orbitals and the energy between them is defined as the magnitude of crystal field splitting (∆o).

Ligands that cause a large crystal field splitting such as CN^- are called strong field ligands. They lead to the formation of diamagnetic species. Strong field ligands occur towards the end of the spectrochemical series of ligands.

Hence the complex, Fe(CN)6 4− is diamagnetic because the cyanide ion is a strong field ligand that causes the six d-electrons present to pair up in a low spin arrangement.

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2 years ago

If the human body were a car, glucose would be:

NeTakaya

If the human body were a car, glucose would be the gasoline.
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2 years ago

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Nana76 [90]

Answer:

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Explanation:

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2 years ago

Please help!!

Sati [7]

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Before calculating the limiting and excess reactant, it is important to balance the equation first by stoichiometry.

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Since the reaction is already balanced, we can now identify which is the limiting and excess reagent.

First, we need to determine the number of moles of each chemical in the equation. This is crucial for determining the limiting and excess reagent.

Assuming that there is the same amount of solution X for each reactant

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The result showed that the crystal violet has lesser amount than NaOH. Thus, the limiting reactant in this chemical reaction is crystal violet and the excess reactant is NaOH.

3 0

2 years ago