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2 years ago

Consider a 175.7 g sample of the compound manganese(IV) perchlorate.

Chemistry

1 answer:

kramer2 years ago

6 0

Answer:

6.21 moles O

Explanation:

To find the moles of oxygen, you need to (1) convert grams Mn(ClO₄)₄ to moles Mn(ClO₄)₄ (via molar mass) and then (2) convert moles Mn(ClO₄)₄ to moles O (via mole-to-mole ratio from formula subscripts). It is important to arrange the conversions/ratios in a way that allows for the cancellation of units.

Molar Mass (Mn(ClO₄)₄): 452.74 g/mol

1 Mn(ClO₄)₄ = 1 Mn and 4 Cl and 16 O

175.7 g Mn(ClO₄)₄ 1 mole 16 moles O
--------------------------- x ------------------- x --------------------------- = 6.21 moles O
452.74 g 1 mole Mn(ClO₄)₄

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0.0625 mol of an ideal gas is contained within a 1.0000 Lvolume container. Its pressure is 142,868 Pa and temperature is X K . W

aliya0001 [1]

Answer: The temperature of the ideal gas is $2.75\times 10^2K$

Explanation:

To calculate the temperature, we use the equation given by ideal gas equation:

$PV=nRT$

where,

P = Pressure of the gas = 142,868 Pa = 142.868 kPa (Conversion factor: 1 kPa = 1000 Pa)

V = Volume of gas = 1.0000 L

n = number of moles of ideal gas = 0.0625 moles

R = Gas constant = $8.31\text{L kPa }mol^{-1}K^{-1}$

T = temperature of the gas = ?

Putting values in above equation, we get:

$142.868kPa\times 1.0000=0.0625mol\times 8.31\text{L kPa }mol^{-1}K^{-1}\times T\\\\T=275K=2.75\times 10^2K$

Hence, the temperature of the ideal gas is $2.75\times 10^2K$

8 0

3 years ago

A gas originally at 27 °c and 1.00 atm pressure in a 2.6 l flask is cooled at constant pressure until the temperature is 11 °c.

elena55 [62]

Charles law gives the relationship between volume and temperature of gas at constant pressure
it states that at constant pressure, volume of gas is directly proportional to temperature
V/T = k
where V - volume T - temperature and k - constant
$\frac{V1}{T1} = \frac{V2}{T2}$
parameters for the first instance are on the left side of the equation and parameters for the second instance are on the right side of the equation
T1 - temperature in Kelvin - 27 °C + 273 = 300 K
T2 - 11 °C + 273 = 284 K
substituting the values in the equation
2.6 L / 300 K = V / 284 K
V = 2.46 L
New volume of the gas is 2.46 L

8 0

3 years ago

Consider the pka (3.75) of formic acid, h-cooh as a reference. with appropriate examples, show how inductive, dipole, and resona

Luden [163]

Formic acid is the simplest carboxylic acid with a structure of HCOOH and has a pka of 3.75. The pka refers to the acidity of the molecule, which in this example refers to the molecules ability to give up the proton of the O-H. A decrease in the pka value corresponds to an increase in acidity, or an increase in the ability to give up a proton. When an acid gives up a proton, the remaining anionic species (in this case HCOO-) is called the conjugate base, and an increase in the stability of the conjugate base corresponds to an increase in acidity.

The pka of a carboxylic can be affected greatly by the presence of various functional groups within its structure. An example of an inductive effect changing the pka can be shown with trichloroacetic acid, Cl3CCOOH. This molecule has a pka of 0.7. The decrease in pka relative to formic acid is due to the presence of the Cl3C- group, and more specifically the presence of the chlorine atoms. The electronegative chlorine atoms are able to withdraw the electron density away from the oxygen atoms and towards themselves, thus helping to stabilize the negative charge and stabilize the conjugate base. This results in an increase in acidity and decrease in pka.

The same Cl3CCOOH example can be used to explain how dipoles can effect the acidity of carboxylic acids. Compared to standard acetic acid, H3CCOOH with a pka of 4.76, trichloroacetic acid is much more acidic. The difference between these structures is the presence of C-Cl bonds in place of C-H bonds. A C-Cl bond is much more polar than a C-H bond, due the large electronegativity of the chlorine atom. This results in a carbon with a partial positive charge and a chlorine with a partial negative charge. In the conjugate base of the acid, where the molecule has a negative charge localized on the oxygen atoms, the dipole moment of the C-Cl bond is oriented such that the partial positive charge is on the carbon that is adjacent to the oxygen atoms containing the negative charge. Therefore, the electrostatic attraction between the positive end of the C-Cl dipole and the negative charge of the anionic oxygen helps to stabilize the entire species. This level of stabilization is not present in acetic acid where there are C-H bonds instead of C-Cl bonds since the C-H bonds do not have a large dipole moment.

To understand how resonance can affect the pka of a species, we can simply compare the pka of a simple alcohol such as methanol, CH3OH, and formic acid, HCOOH. The pka of methanol is 16, suggesting that is is a very weak acid. Once methanol gives up that proton to become the conjugate base CH3O-, the charge cannot be stabilized in any way and is simply localized on the oxygen atom. However, with a carboxylic acid, the conjugate base, HCOO-, can stabilize the negative charge. The lone pair electrons containing the charge on the oxygen atom are able to migrate to the other oxygen atom of the carboxylic acid. The negative charge can now be shared between the two electronegative oxygen atoms, thus stabilizing the charge and decreasing the pka.

3 0

3 years ago

In a redox reaction, what role does the reducing agent play?

viktelen [127]

So the oxidizing agent will receive electrons from the reducing agent and the oxidation agent will take electrons from the reducing agent.

3 0

3 years ago

Read 2 more answers

Calculate either [ H 3 O + ] or [ OH − ] for each of the solutions.

STALIN [3.7K]

Answer: Solution A : $[H_3O^+]=0.300\times 10^{-7}M$

Solution B : $[OH^-]=0.107\times 10^{-5}M$

Solution C : $[OH^-]=0.177\times 10^{-10}M$

Explanation:

pH or pOH is the measure of acidity or alkalinity of a solution.

pH is calculated by taking negative logarithm of hydrogen ion concentration and pOH is calculated by taking negative logarithm of hydroxide ion concentration.

$pH=-\log[H_3O^+]$