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3 years ago

How many grams of a 5.5% solution can be prepared from 25 kg KCl

Chemistry

1 answer:

AnnZ [28]3 years ago

7 0

Answer:

The percentage concentration of any solution is most commonly expressed as mass percent:

Mass % of any component of the solution =

(Mass of the component in the solution / Total mass of the solution) x 100

Other methods are:

Volume percentage:

Volume % of a component =

(Volume of the component/Total volume of the solution) x 100

Mass by volume percentage:

It is the mass of solute dissolved in 100 mL of the solution.

i.e. Mass by Volume percentage =

(Mass of solute in grams/Volume of solution in mL) x 100

Here's a point to be kept in mind :

Whenever we say mass or volume of the solution, you need to add the respective masses and volumes of ALL the components of the solution. Do NOT commit the error of taking the mass or volume of only the solute or solvent in the denominators of the above expressions.

The concentration of a solution is most of the time expressed as the number of moles of solute present in 1 Liter of the solution (also called molarity )

(There are also other ways to express concentration. Please follow this link. )

EXAMPLE:

(a) If 25 moles of NaCl are present in 100 L of a solution wherein H2O is the solvent, then the concentration of the solution is

100

0.25

mol⋅L

−

(b) What is the molarity of a solution prepared by dissolving 15.0 g of sodium hydroxide in enough water to make a total of 225 mL of solution?

Solution

Calculate the number of moles of solute present.

Moles of NaOH = 15.0 g NaOH ×

mol NaOH

40.00

g NaOH

= 0.375 mol NaOH

Calculate the number of litres of solution present.

Volume = 225 mL ×

1000

= 0.225 L soln

Divide the number of moles of solute by the number of litres of solution.

Molarity =

0.375

mol

0.225

= 1.67 mol/L

Explanation:

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Vapor dispersion:

Contact [7]

Answer:

c. reduces the concentration of the hazardous material in the air.

Explanation:

Pollution can be defined as the physical degradation or contamination of the environment through an emission of harmful, poisonous and toxic chemical substances.

Particulate population is a form of pollution that is responsible for the degradation of the environment.

Particulate matter is also referred to as particle pollution or atmospheric aerosol particles and it can be defined as a complex microscopic mixture of liquid droplets and solid particles that are suspended in air. Other forms of particle pollution includes space debris and marine debris.

Some examples of particulate pollution are dusts, soot, dirt, smoke, etc.

Basically, various anthropogenic activities such as construction and agriculture are primary sources of particulate matter because they're capable of causing particle pollution on their own. The other sources of particle pollution is the secondary source which includes factories, cars, trucks, etc.

Vapor dispersion can be defined as a process which is typically used for removing particle pollutants from the atmosphere through the use of vapor or steam.

Hence, vapor dispersion when adopted, reduces the concentration of the hazardous material such as soot, dusts, smoke, etc., in the air.

5 0

3 years ago

Which statement about the temperatures of phase changes and electrostatic forces holding the molecules is correct?(1 point)

lubasha [3.4K]

The temperature at which phase changes occur is highly dependent on the electrostatic forces between the molecules in the substance.

The forces that hold molecules together are called intermolecular forces. These intermolecular forces affect the temperature at which phase changes occur. The statement about phase changes and electrostatic forces that is correct is that; "the temperatures at which a substance changes phases indicate the relative strength of the forces between molecules in the substance."

There are three states of matter, solid liquid and gas. The order of intermolecular forces in all the states of matter are not the same. The order of strongest collective electrostatic forces to weakest collective electrostatic forces is; solid, liquid, gas.

When water boils, the forces between water molecules break, and the bonds between the atoms in water are unchanged.

When a sample of calcium carbonate is cooled, the forces strengthen, and the molecule structure becomes more rigid.

If the boiling point of acetone is lower than the boiling point of ethanol, then, the intermolecular forces in ethanol are stronger than the intermolecular forces in acetone.

Learn more about phase changes: brainly.com/question/671212

4 0

2 years ago

explain why the first ionization energy of krypton is greater than the first ionization energy of bromine

4vir4ik [10]

Answer:

The atomic radius of krypton is similar to that of bromine. However, the effective nuclear charge of krypton is greater than that of bromine.

Explanation:

Ionizing an atom require moving an electron from the electron cloud of the atom to a point infinitely far away from the atom. The first ionization energy of this atom is the energy change in this process.

The electron and the nucleus are oppositely-charged. There is an electrostatic force between the two. Removing the electron requires overcoming this attraction. The size of the energy input depends on the electrostatic potential energy of the electron (the gravitational potential energy is much smaller than the electrostatic potential energy.) The separation between the electron and the nucleus is much larger than their radii. Both objects can be considered as point charges. Coulomb's Law gives the electrostatic potential energy of the two point charge that are close to each other.

$\displaystyle \text{Electrostatic Potential Energy} = -\frac{k\cdot (q_1\cdot q_2)}{r}$ ,

where

$k$ is Coulomb's constant,
$q_1$ and $q_2$ are the two charges, and
$r$ is the separation between the two charges.

Krypton and bromine are right next to each other in the same period. Their atomic radii will be similar to each other. The separation $r$ between the outermost electron and the nucleus will also be similar for the two elements.

The first charge $q_1$ can be the electron. However, data show that for elements after helium, the second charge $q_2$ is smaller than the sum of charges on all protons in the nucleus. It turns out that the inner shell electrons (all of which are also negative) repel electrons in the outermost valence shell. The effective nuclear charge $Z_\text{eff}$ of a neutral atom is <em>approximately</em> the same as the number of protons minus the number of non-valence electrons. That number will be slightly larger for krypton than for bromine. As a result, the electrostatic potential energy on a 4p (the outermost orbital for both Kr and Br) electron of krypton will be more negative than that on a 4p electron in bromine. Removing that electron will take more energy in Kr than in Br. The first ionization energy of Kr is hence greater than that of Br.

8 0

3 years ago

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Why do people use symbols and numbers instead of equations in chemistry?

AleksAgata [21]

Answer:

people can answer quicker withought writing out the equation.

C6H1206 or a hexagon??

6 0

4 years ago

Fission creates large amounts of: A.uranium B.air pollution C.carbon dioxide D.radioactive waste

Vaselesa [24]

Answer: -

Fission creates large amounts of radioactive waste.

Explanation: -

During nuclear fission, by products are formed. These by products are radioactive in nature. They give radiation. These radiation causes a lot of harm to humans including cancer and mutations.

Thus, Fission creates large amounts of radioactive waste.

5 0

4 years ago

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