Calculate the molality of a solution containing 22.75 g of glycerol (C3H8O3) in 79.6 g of ethanol (C2H5OH).

Answers

Answer 1
Answer:

Answer:

3.11 mol/kg

Explanation:

Molality M = number of moles of solute, n/mass of solvent, m

To calculate the number of moles of glycerol (C₃H₈O₃) in 22.75 g of glycerol, we find its molar (molecular) mass, M',

So, M' = 3 × atomic mass of carbon + 8 × atomic mass hydrogen + 3 × atomic mass of oxygen

= 3 × 12 g/mol + 8 × 1 g/mol + 3 × 16 g/mol = 36 g/mol + 8 g/mol + 48 g/mol = 92 g/mol.

So, number of moles of glycerol, n = m'/M' where m' = mass of glycerol = 22.75 g and M' = molecular mass of glycerol = 92 g/mol

So, n = m'/M'

n = 22.75 g/92 g/mol

n = 0.247 mol

So, the molality of the solution M = n/m

Since m = mass of ethanol = 79.6 g = 0.0796 kg, substituting the value of n into the equation, we have

M = 0.247 mol/0.0796 kg

M = 3.11 mol/kg

So, the molality of the solution is 3.11 mol/kg.


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You are given a glass rod that is negatively charged and a pinwheel that has a negative charge. What will happen when the glass rod is brought close to the pinwheel? Why? ​

Answers

Answer:

they will repel each other

Explanation:

When these two are brought close to one another they will repel each other. This is similar to what happens with magnets, when two objects share the same polarity one object will create a repulsive force upon the second object and push it away. This repellent force is caused by an electric field from the same charged electrons in the atoms of the object. Since in this case both the glass rod and the pinwheel have a negative charge they will repel each other when they come into proximity of one another.

In the United States, volume of irrigation water is usually expressed in acre-feet. One acre-foot is a volume of water sufficient to cover 1 acre of land to a depth of 1 ft (640 acres = 1 mi2, 1 mi = 5280 ft). The principal lake in the California Water Project is Lake Oroville, whose water storage capacity is listed as 3.54 x 106 acre-feet. Express the volume of Lake Oroville in (a) cubic feet, (b) cubic meters, and (c) US gallons.

Answers

Answer:

a) V = 1.542 E11 ft³

b) V = 4367011968 m³

c) V = 1.1535 E12 us gal

Explanation:

Acre surface is defined as 66 by 660 feet at a depth of one foot:

⇒ Vacre-foot = 66ft*660ft*1ft = 43560 ft³

lake:

a)  V = 3.54 E6 acre-feet * ( 43560 ft³ / acre-foot ) = 1.542 E11 ft³

b) V = 1.542 E11 ft³ * ( 0.02832m³ / ft³ ) = 4367011968 m³

c) V = 1.542 E11 ft³ * ( 7.48052 us gal/ft³ ) = 1.1535 E12 us gal

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Answers

Answer: The agents of soil erosion are the same as of other types of erosion for example water, ice, wind, and gravity. Soil erosion is more likely where the ground has been disturbed by agriculture, grazing animals, logging, mining, construction, and recreational activities.Basically what I mean is some causes of solid loss is mining, construction

Give an example of coupling reaction​

Answers

Answer:

An example is the formation of ATP, which is an endergonic process and is coupled to the dissipation of a proton gradient.

Explanation:

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Of the following elements, which one has the lowest first ionization energy?boron carbon aluminum silicon

Answers

Answer:

Boron

Explanation:

Because it has a complete 2s orbital and therefore, an increased shielding of the 2s orbital will reduce the ionisation energy.

Final answer:

Among boron, carbon, aluminum, and silicon, aluminum has the lowest first ionization energy due to its position on the periodic table, which is further to the left and in a higher period than the other elements.

Explanation:

Ionization energy refers to the energy necessary to remove an electron from an atom in its gaseous state. The element with the lowest first ionization energy among boron, carbon, aluminum, and silicon is aluminum. Ionization energy increases from left to right across a period in the periodic table and from bottom to top in a group. Thus, aluminum, being to the left of boron, carbon, and silicon, has the lowest first ionization energy. Furthermore, aluminum is in the third period, which is below boron and carbon's second period.

Learn more about Ionization Energy here:

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Which is the best description of a molecule?

Answers

Answer:

a molecule is the smallest particle in a chemical element or compound that has the chemical properties of that element or compound. Molecules are made up of atoms that are held together by chemical bonds. These bonds form as a result of the sharing or exchange of electrons among atoms

Answer:

: A molecule is the smallest particle in a chemical element or compound that has the chemical properties of that element or compound. Molecules are made up of atoms that are held together by chemical bonds. These bonds form as a result of the sharing or exchange of electrons among atoms.

Explanation:

i hope its right