Not the best in chemistry please help

Which factor is generally responsible for high melting points?

kherson [118]

The factor that is generally responsible for higher melting point is intermolecular forces. The compounds that are covalent in nature are made of molecules rather than ions. It has been seen that some of the covalent compounds have polar molecules at one end, due to which the one end has more electronegative force than the other. The electrostatic force that is bounding the compound is the main cause of higher melting point of this compound. So it is true that with the increase of polarity of a compound creates higher melting point. .. hope I helped

3 0

2 years ago

What is the vapor pressure of the solution if 35.0 g of water is dissolved in 100.0 g of ethyl alcohol at 25 ∘C? The vapor press

masya89 [10]

Answer: The vapor pressure of the solution is 43.55 mmHg

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

For water:

Given mass of water = 35.0 g

Molar mass of water = 18 g/mol

Putting values in equation 1, we get:

$\text{Moles of water}=\frac{35.0g}{18g/mol}=1.944mol$

For ethyl alcohol:

Given mass of ethyl alcohol = 100.0 g

Molar mass of ethyl alcohol = 46 g/mol

Putting values in equation 1, we get:

$\text{Moles of ethyl alcohol}=\frac{100.0g}{46g/mol}=2.174mol$

Total moles of solution = [1.944 = 2.174] moles = 4.118 moles

Mole fraction of a substance is given by:

$\chi_A=\frac{n_A}{n_A+n_B}$

For water:

$\chi_{\text{water}}=\frac{n_{\text{water}}}{n_{\text{water}}+n_{\text{ethyl alcohol}}}$

$\chi_{water}=\frac{1.944}{4.118}=0.472$

For ethyl alcohol:

$\chi_{\text{ethyl alcohol}}=\frac{n_{\text{ethyl alcohol}}}{n_{\text{water}}+n_{\text{ethyl alcohol}}}$

$\chi_{\text{ethyl alcohol}}=\frac{2.174}{4.118}=0.528$

Dalton's law of partial pressure states that the total pressure of the system is equal to the sum of partial pressure of each component present in it.

To calculate the vapor pressure of the solution, we use the law given by Dalton, which is:

$P_T=\sum_{i=1}^n (p_i\times \chi_i)$

Or,

$P_T=[(p_{\text{water}}\times \chi_{\text{water}})+(p_{\text{ethyl alcohol}}\times \chi_{\text{ethyl alcohol}}$

We are given:

Vapor pressure of water = 23.8 mmHg

Vapor pressure of ethyl alcohol = 61.2 mmHg

Putting values in above equation, we get:

$p_T=[(23.8\times 0.472)+(61.2\times 0.528)]\\\\p_T=43.55mmHg$

Hence, the vapor pressure of the solution is 43.55 mmHg

4 0

3 years ago

Given pH = 3.50 Find: [H3O+] and [OH-] Is this acidic, basic or neutral?

lys-0071 [83]

Answer:

Explanation:

Given parameters:

pH = 3.50

Unknown:

concentration of [H₃0⁺] = ?

concentration of [OH⁻] = ?

Solution:

In order to find the unknown, we use some simple expressions which best explains the pH scale and the equilibrium systems of aqueous solutions.

pH = -log₁₀[H₃O⁺]

[H₃O⁺] = inverse log₁₀ (-pH) = $10^{-pH}$ = $10^{-3.5}$

[H₃O⁺] = 3.2 x 10⁻⁴moldm⁻³

For the [OH⁻]:

we use : pOH = -log₁₀ [OH⁻]

Recall: pOH + pH = 14

pOH = 14 - pH = 14 - 3.5 = 10.5

Now we plug the value of pOH into pOH = -log₁₀ [OH⁻]

[OH⁻] = $10^{-pOH}$

[OH⁻] = $10^{-10.5}$ = 3.2 x 10⁻¹¹moldm⁻³

The solution is acidic as the concentration of H₃0⁺ is more than that of the OH⁻ ions.

8 0

3 years ago

2. Fluorine gas exerts a pressure of 1.2 atm. When the

Mariana [72]

Answer:

look at the photo........................

6 0

2 years ago

7th grade Science//POINTS AND BRAINLIEST...AND plz hurry... Function of Organelles- Give the functions of the listed organelles:

vova2212 [387]

Answer: Chloroplast - The organelles are only found in plant cells and some protists such as algae. ... Chloroplasts work to convert light energy of the Sun into sugars that can be used by cells. The entire process is called photosynthesis and it all depends on the little green chlorophyll molecules in each chloroplast.

Mitochondria - are known as the powerhouses of the cell. They are organelles that act like a digestive system which takes in nutrients, breaks them down, and creates energy rich molecules for the cell. The biochemical processes of the cell are known as cellular respiration.

The cell membrane- controls the movement of substances in and out of cells and organelles. In this way, it is selectively permeable to ions and organic molecules.

Cytoplasm - is present within the cell membrane of all cell types and contains all organelles and cell parts. Cytoplasm has various functions in the cell. ... Cytoplasm is responsible for giving a cell its shape. It helps to fill out the cell and keeps organelles in their place.

Nucleus - This organelle has two major functions: it stores the cell's hereditary material, or DNA, and it coordinates the cell's activities, which include growth, intermediary metabolism, protein synthesis, and reproduction (cell division). Only the cells of advanced organisms, known as eukaryotes, have a nucleus.

Ribosomes - are a cell structure that makes protein. Protein is needed for many cell functions such as repairing damage or directing chemical processes. Ribosomes can be found floating within the cytoplasm or attached to the endoplasmic reticulum. ... Proteins are an essential part of all cells.

Endoplasmic reticulum (ER) - in biology, a continuous membrane system that forms a series of flattened sacs within the cytoplasm of eukaryotic cells and serves multiple functions, being important particularly in the synthesis, folding, modification, and transport of proteins .

Vacuoles - are membrane-bound sacs within the cytoplasm of a cell that function in several different ways. In mature plant cells, vacuoles tend to be very large and are extremely important in providing structural support, as well as serving functions such as storage, waste disposal, protection, and growth.

Lysosome - Inside a cell, numerous organelles function to remove wastes. One of the key organelles involved in digestion and waste removal is the lysosome. Lysosomes are organelles that contain digestive enzymes. They digest excess or worn out organelles, food particles, and engulfed viruses or bacteria.

Chromosomes - are the thread-like structure found in the nuclei of both animal and plant cells. They are made of protein and one molecule of deoxyribonucleic acid (DNA) Chromosomes are important to this process to ensure the DNA is accurately replicated.

The nucleolus - makes ribosomal subunits from proteins and ribosomal RNA, also known as rRNA. It then sends the subunits out to the rest of the cell where they combine into complete ribosomes. Ribosomes make proteins; therefore, the nucleolus plays a vital role in making proteins in the cell.

Vesicles - are small cellular containers that perform a variety of functions. They can be used to move molecules, secrete substances, digest materials, or regulate the pressure in the cell.

The cell wall - is the protective, semi-permeable outer layer of a plant cell. A major function of the cell wall is to give the cell strength and structure, and to filter molecules that pass in and out of the cell.

Took some time hope it helped !!! <3

Explanation:

6 0

3 years ago