Chemistry, 12.02.2020 20:24, favre22fs

A liquid solvent is added to a flask containing an insoluble solid. The total volume of the solid and liquid together is 87.0 mL. The liquid solvent has a mass of 49.7 g and a density of 0.865 g/mL. Determine the mass of the solid given its density is 2.75 g/mL.

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answered: jmitial

The mass of solid is 81.24 grams

Explanation:

We are given:

Volume of solid and liquid together = 87.0 mL

To calculate density of a substance, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$ ......(1)

For liquid:

Density of liquid solvent = 0.865 g/mL

Mass of liquid solvent = 49.7 g

Putting values in equation 1, we get:

$0.865g/mL=\frac{49.7g}{\text{Volume of liquid solvent}}\\\\\text{Volume of liquid solvent}=\frac{49.7g}{0.865g/mL}=57.46mL$

For Solid:

Density of solid = 2.75 g/mL

Volume of solid = [87.0 - 57.46] mL = 29.54 mL

Putting values in equation 1, we get:

$2.75g/mL=\frac{\text{Mass of solid}}{29.54mL}\\\\\text{Mass of solid}=(2.75g/mL\times 29.54mL)=81.24g$

Hence, the mass of solid is 81.24 grams

answered: Guest

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.

answered: Guest

Heat is involved in chemical change in two ways; chemical changes either result in heat being added to or removed from an object, and chemical changes require a certain amount of heat before they can take place.