What is the uppermost, horizontal area of a page?

I have little or no rainfall for long periods of time. I cause death to all living things because of lack of water. What am I?

Doss [256]

Answer:

a drought !

- little to no water causes it

- it causes for organisms to die and organisms need water !

4 0

3 years ago

Compound Y has a distribution coefficient of 4.0 when extracted from water with chloroform, with Y being more soluble in chlorof

Aleks04 [339]

Answer:

There are needed 3 extractions to extract at least 95%

Explanation:

The distribution coefficient of a compound is defined as the ratio in concentration of the compound in the organic solvent and the concentration in the aqueous solution:

K = Concentration organic solvent / Concentration in water

Assuming as initial amount of the organic solvent: 100% and X as the amount of Y that is extracted

First extraction:

4 = X / 10mL / (100-X) / 50mL

4 = 50X / 1000-X

4000 - 4X = 50X

4000 = 54X

X = 74.1%

In the first extraction, 74.1% of Y is extracted

And will remain: 100 - 74.1 = 25.9%

Second extraction:

4 = X / 10mL / (25.9-X) / 50mL

4 = 50X / 259-X

1036 - 4X = 50X

1036 = 54X

X = 19.2%

In the second extraction, 19.2% of Y is extracted

And will remain: 25.9 - 19.2 = 6.7%

Third extraction

4 = X / 10mL / (6.7-X) / 50mL

4 = 50X / 67-X

268 - 4X = 50X

268 = 54X

X = 5.0%

In the first extraction, 5.0% of Y is extracted

And are extracted:

74.1% + 19.2% + 5.0% = 98.3%

That means there are needed 3 extractions to extract at least 95%

4 0

2 years ago

II. Binding Forces A. Write a brief, one or two sentence, description of each binding force listed below. 1. London dispersion f

Leya [2.2K]

Answer:

All description is given in explanation.

Explanation:

Van der Waals forces:

It is the general term used to describe the attraction or repulsion between the molecules. Vander waals force consist of two types of forces:

1. London dispersion forces

2. Dipole-dipole forces

1. London dispersion forces:

These are the weakest intermolecular forces. These are the temporary because when the electrons of atoms come close together they create temporary dipole, one end of an atom where the electronic density is high is create negative pole while the other becomes positive . These forces are also called induce dipole- induce dipole interaction.

2. Dipole-dipole forces:

These are attractive forces , present between the molecules that are permanently polar. They are present between the positive end of one polar molecules and the negative end of the other polar molecule.

Hydrogen bonding:

It is the electrostatic attraction present between the atoms which are chemically bonded. The one atom is hydrogen while the other electronegative atoms are oxygen, nitrogen or flourine. This is weaker than covalent and ionic bond.

Ionic bond or electrostatic attraction:

It is the electrostatic attraction present between the oppositely charged ions. This is formed when an atom loses its electron and create positive charge and other atom accept its electron and create negative charge.

Hydrophobic interaction:

It is the interaction between the water and hydrophobic material. The hydrophobic materials are long chain carbon containing compound. These or insoluble in water.

Covalent bond:

These compounds are formed by the sharing of electrons between the atoms of same elements are between the different element's atoms. The covalent bond is less stronger than ionic bond so require less energy to break as compared to the energy require to break the ionic bond.

5 0

3 years ago

What are essential elements in plants?

madam [21]

Answer:

Chlorophyll is one. I can't quite remember other

5 0

3 years ago

Draw an energy diagram for an endothermic and exothermic reaction and label the diagram

just olya [345]

Energy diagram for and endothermic and exothermic reaction