A 85.2 g copper bar was heated to 221.32 degrees Celsius and placed in a coffee cup calorimeter containing 4250 mL of water at 2

Answer:

La masa molar del compuesto es: 168.82 g/mol

La masa molar del gas es: 16.38 g/mol

Explanation:

(a)

Utilizando la ecuación de gases ideales:

donde,

P es la presión

V es el volumen

n es el número de moles

T es la temperatura

R es la constante de los gases, cuyo valor es = 0.0821 L.atm/K.mol

Además,

Moles = masa (m) / Masa molar (M)

La densidad (d) = Masa (m) / Volumen (V)

Así, la ecuación de gases ideales se puede expresar como:

Dado que:-

Presión = 20 kPa = 20000 Pa

La expresión para la conversión de presión en Pascal a presión en atm se muestra a continuación:

P (Pa) = P (atm)

20000 Pa = atm

Presión = 0.1974 atm

Temperatura = 330 K

d = 1.23 kg/m³ = 1.23 g/L

Masa molar =?

Aplica la fórmula:

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

⇒M = 168.82 g/mol

La masa molar del compuesto es: 168.82 g/mol

(b)

Dado que:

Presión = 152 Torr

Temperatura = 298 K

Volumen = 250 cm³ = 0.25 L

Utilizando la ecuación de gases ideales:

R =

Aplicando la fórmula:

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

⇒n = 0.002045 moles

Dado que:

Masa del gas = 33.5 mg = 0.0335 g

Masa molar =?

La fórmula para calcular los moles se muestra a continuación:

Así,

La masa molar del gas es: 16.38 g/mol

While the original inquiry is incomplete, the comprehensive question is:

Many chemicals can illustrate spots on a TLC plate that have been processed and dried. The permanganate used in the video creates yellow spots against a purplish background, taking advantage of the oxidizing capability of basic permanganate (MnO4), which outperforms chromic acid as an oxidizing agent. Chromic acid can also be employed to visualize spots, resulting in a green hue on the yellow background, indicating oxidation. So, can chromic acid be conveniently used to visualize spots when tracking a reaction converting an alcohol into a ketone? What observations are anticipated if one attempts this? Furthermore, if a small amount of alcohol is included in a solvent mixture for eluting your TLC plate, why must the plate be fully dried before visualizing the spots with an oxidizing agent like permanganate or chromic acid?

Answer:

Typically, using chromic acid to visualize spots during the conversion of alcohol to ketone is not feasible. The alcohol (substrate) will convert into its respective ketone due to the presence of chromic acid, causing the spots for the product and the reactant to align horizontally. This alignment complicates differentiation between the spots, making chromic acid unsuitable for this purpose.

It's vital to ensure that the plate is completely dry before observing spots with an oxidizing agent, even if alcohol is present in the solvent mixture. Incomplete drying could lead to oxidation of the alcohol by the oxidizing agent, resulting in transformation to carboxylic acid or ketone, thereby creating a new spot.

Answer: 0.0007 moles of are released when the temperature rises.

Explanation:

To determine the moles, we utilize the ideal gas law, as follows:

where,

P = gas pressure = 1.01 bar

V = gas volume = 1L

R = gas constant =

• Calculated moles at T = 20° C

The gas temperature = 20° C = (273 + 20)K = 293K

Substituting values into the equation gives:

• Calculated moles at T = 25° C

The gas temperature = 25° C = (273 + 25)K = 298K

Substituting values into the equation gives:

• Released moles =

Therefore, 0.0007 moles of are released when the temperature increases from 20° C to 25° C.

Question 1.

The accurate statement is " Aluminium, as it belongs to group 13 and contains three valence electrons. The Lewis dot structure illustrates the number of valence electrons in a single atom. By referencing the periodic table, we identify the element based on its valence electrons. Indeed, aluminium possesses 3 valence electrons and is located in Group 13 of the periodic table.

Question 2.

The correct count is 5. The outer layer of electrons is termed the valence shell, containing what we refer to as valence electrons. Here, the outermost shell corresponds to n=3, meaning all electrons in this layer are classified as valence electrons. While we do have subshells (3s and 3p), they indicate the spatial region where an electron may be located but do not clarify valence.

Question 3.

Chlorine possesses 7 valence electrons, Neon has 8 valence electrons, Phosphorus contains 5 valence electrons, Sulfur has 6 valence electrons. The position of an element in the periodic table aids in determining its electron configuration, and the group number provides insights into the number of valence electrons. By merely checking the periodic table's group number, we can ascertain the valence electrons.

Question 4.

The assertion is True. As atomic orbitals fill, the energy levels extend farther from the nucleus. The outermost orbital capable of being filled with electrons is known as the valence shell, and the electrons within are termed valence electrons. This characteristic defines the reactivity of particular elements.

Question 5.

The atom with the electron configuration contains an unpaired electron in its 3s orbital, rendering it unstable. Meanwhile, the element with 7 valence electrons requires just one additional electron to complete its octet. Therefore, the atom loses an electron to bond with the element holding 7 valence electrons. Consequently, the element acquires a positive charge, while the one with 7 valence electrons becomes negatively charged, leading to the formation of an ionic bond.

Answer:

Joe correctly mixed the solution.

Explanation:

When evaluating both procedures, it's evident that both Jennifer and Joe weighed the same amount of potassium phosphate, which isn’t the variable here.

The difference is that Jennifer added the solid to 1.0 liters of water, resulting in a final volume greater than 1.0 L, thus her concentration will be lower than 1.0 M.

Joe's solution has a final volume of 1.0 L, which is why his preparation is accurate.