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1 day ago

The temperature of the areas surrounding Farmington before Storm 1 and before Storm 2 was about 8°C, and there was the same amou

nt of water vapor in the air. Storm 1 had more rainfall than Storm 2.

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A characteristic feature of any form of chromatography is the ________.a. calculation of an Rf value for the molecules separated

castortr0y [3046]

Answer: The right choice is (c) application of both a mobile phase and a stationary phase.

Explanation:

Chromatography: This refers to a technique for separating a mixture where the mixture is distributed between two phases at varying rates, one being stationary and the other moving.

Mobile phase: The component in which the mixture is dissolved is referred to as the mobile phase.

Stationary phase: This is an adsorbent medium that remains in place while a liquid or gas passes over its surface, thus remaining stationary.

Consequently, a key characteristic of any chromatography technique involves utilizing both a mobile and a stationary phase.

4 0

3 months ago

"A sample of silicon has an average atomic mass of 28.084amu. In the sample, there are three isotopic forms of silicon. About 92

lorasvet [2795]

Answer: The percentage abundance for $_{14}^{30}\textrm{Si}$ isotope is 3.09 %.

Explanation:

The average atomic mass of an element is calculated by taking the sum of the masses of all isotopes weighted by their respective natural fractional abundances.

To compute average atomic mass, the following formula is applied:

$\text{Average atomic mass }=\sum_{i=1}^n\text{(Atomic mass of an isotopes)}_i\times \text{(Fractional abundance})_i$ .....(1)

From the information provided:

Let the fractional abundance for $_{14}^{28}\textrm{Si}$ isotope be 'x'

For $_{14}^{28}\textrm{Si}$ isotope:

Mass of $_{14}^{28}\textrm{Si}$ isotope = 27.9769 amu

Percentage abundance of $_{14}^{28}\textrm{Si}$ isotope = 92.22 %

Fractional abundance for $_{14}^{28}\textrm{Si}$ isotope = 0.9222

For $_{14}^{29}\textrm{Si}$ isotope:

Mass of $_{14}^{28}\textrm{Si}$ isotope = 28.9764 amu

Percentage abundance for $_{14}^{28}\textrm{Si}$ isotope = 4.68%

Fractional abundance of $_{14}^{28}\textrm{Si}$ isotope = 0.0468

For $_{14}^{30}\textrm{Si}$ isotope:

Mass of $_{14}^{30}\textrm{Si}$ isotope = 29.9737 amu

Fractional abundance for $_{14}^{30}\textrm{Si}$ isotope = x

The average atomic mass of silicon is 28.084 amu

By inserting these values into equation 1, we derive:

$28.084=[(27.9769\times 0.9222)+(28.9764\times 0.0468)+(29.9737\times x)]\\\\x=0.0309$

To convert this fractional abundance into a percentage, multiply by 100:

$\Rightarrow 0.0309\times 100=3.09\%$

This shows that the percentage abundance for $_{14}^{30}\textrm{Si}$ isotope is 3.09 %.

6 0

3 months ago

How much energy is required to vaporize 1.5 KG of aluminum

castortr0y [3046]

The energy needed to vaporize 1.5 kg of aluminum amounts to 16.345 GJ. The heat of vaporization for aluminum is given as ΔHvap = 294000 kJ/mol. The mass of aluminum in this case equals 1.5 kg which converts to 1500 g. We can calculate the number of moles of aluminum using the formula: Mass of aluminum/(Molar Mass of aluminum). The Molar Mass of aluminum stands at 26.98 g/mol. Using this information, Number of moles calculates to 1500/26.98, which equals 55.6 moles. The total energy required can be expressed as the product of the heat of vaporization and the number of moles of aluminum, so the energy required calculates to 294000 × 55.6, resulting in 16345441.0675 kJ or approximately 16.345 GJ.

5 0

2 months ago