Chemistry, 04.06.2021 18:50 lulu5563

Identify the calculations possible using only 28.02 g/mol as a conversion factor. Select one or more:

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Answer from: demigod0701

The question is incomplete, the complete question is:

Identify the calculations possible using only 28.02 g/mol as a conversion factor. Select one or more:

(a): Calculate the grams of N_2 in 10.58 L of nitrogen gas

(b): Calculate the grams of N_2 in $5.03\times 10^{20}$ moles of nitrogen gas

(c): Calculate the moles of N_2 molecules in 3.94 grams of nitrogen gas

(d): Calculate the moles of N_2 molecules in 4.73 L of nitrogen gas

The correct options are (b) and (c).

Explanation:

We are given:

Molar mass of N_2 = 28.02 g/mol

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

At STP conditions:

1 mole of gas occupies 22.4 L of volume

For the given options:

(a): Volume is given and to calculate the mass of N_2 , we need to use both the conversion factors above.

The equation formed will be:

Mass of N_2 = $\frac{1mol}{22.4L}\times 10.58L\times 28.02 g/mol$

(b): Moles are given and to calculate the mass of N_2 , we need only the first conversion factor.

The equation formed will be:

Mass of N_2 = $(5.03\times 10^{20}mol)\times 28.02g/mol$

(c): Mass is given and to calculate the moles of N_2 molecules, we need only the first conversion factor.

The equation formed will be:

Moles of N_2 molecules = $\frac{3.94 g}{28.02g/mol}$

(d): Volume is given and to calculate the moles of N_2 molecules, we need only the second conversion factor.

The equation formed will be:

Moles of N_2 molecules = $\frac{1mol}{22.4L}\times 4.73L$

Hence, the correct option is (b) and (c)

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.