Chemistry, 20.07.2019 00:30 xcncxgnfxg6487

The vapor pressure of pure ethanol at 60 °c is 0.459 atm. raoult's law predicts that asolution prepared by dissolving 10.0 mmol naphthalene (nonvolatile) in 90.0 mmol ethanol willhave a vapor pressure of atm.

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Answer from: jay13212

Raoult's law is stated as the partial vapor pressure of each component in the mixture of ideal liquids is equal to the vapor pressure of the pure component multiplied by its mole fraction in the mixture. Mathematically, it is expressed as

P = Xi Pi

where P= vapor pressure of solution
Xi = mole fraction of i component
Pi = vapor pressure of pure i component.

In present case, P1 = 0.459 atm and n1 = number of mole of ethanol = 0.090
n2 = number of mole of naphthalene = 0.01

∴ Mole fraction of ethanol = $\frac{n1}{\text{n1 + n2}}$ = $\frac{0.090}{\text{0.090 + 0.010}}$ = 0.9

Thus, vapor pressure of solution = 0.9 X 0.459 = 0.4131 atm.

The vapor pressure of pure ethanol at 60 °c is 0.459 atm. Raoult's law predicts that a solution prepared by dissolving 10.0 mmol naphthalene (nonvolatile) in 90.0 mmol ethanol will have a vapor pressure of 0.4131 atm.

Answer from: Quest

assuming that your periodic table has eighteen columns, you should highlight the four elements in the third column from the left of the table.

explanation

neutral atoms of elements after calcium contain d electrons. the energy of d orbitals of a particular main shell lies between the energy of the s and p orbitals of the next main shell. for example, electrons in the $3d$ have energy higher than those in the $4 s$ orbital while lower than those of the $4 p$ orbital.

by the aufbau principle, electrons fill orbitals one at a time, starting from those of the lowest energy. the $4s$ orbital is therefore filled right after $3p$ orbitals and before $3 d$ orbitals.

potassium has electron configuration $[\text{ar}] 4 s^{1}$ and calcium $[\text{ar}] 4 s^{2}$ . the s orbital of a main shell holds a maximum of two electrons. the next element would thus have the electron configuration $[\text{ar}] 4 s^{2} \; 3d^{1}$ and satisfy the requirements.

a neutral atom of the element contains three electrons on top of the most recent noble gas element. it should thus be placed in the third column of the periodic table. both scandium and yttrium would satisfy the conditions. an aufbau diagram indicates that the 4f orbital is filled before the 5d. however, it appears that exceptions exists for both lanthanum and actinium. neutral atoms of the two d-block elements also demonstrate the $ns^{2} \; (n-1) p^{1}$ and should be highlighted as well.