Why are the melting and boiling points of an
element or a compound are called its fixed points.

A GEL is a semisolid preparation that contains very small solid particles that are suspended in a liquid. A gel always contains an agent (e.g., agarose) that provides stiffness to the preparation.

A gel is a semisolid preparation that contains a gelling agent which provides stiffness to the preparation.

The gelling agent can be, for example, agarose (this gelling agent is used to prepare gels in electrophoresis).

In an agarose gel, agarose molecules are organized into three-dimensional (3D) structures similar to pores, which allow the passage of DNA fragments during electrophoresis.

Learn more about agarose gel here:

https://brainly.com/question/5661562

Answer:

the nature of the bond is covalent.

covalent bonds are bonds between 2 NON-METAL elements. since phosphorus and oxygen are both non-metals, the bond formed between them is covalent.

hope this answers your question!

Answer:

the answer is C

Explanation:

This is because group6 elements are diatomic and when they are chemically combined their subscript 2 cancels out

Answer:

5 significant figures

Explanation:

The zeros as considered when they are in between or after numbers greater than zero.

Ex1: 0.005 = 1 significant figure

Ex2: 0.0050 = 2 significant figure

Ex3: 0.05500= 4 significant figure

Ex4: 5.00 = 1 significant figure

This problem is providing describing a room in which air has a total pressure of 0.987 atm and the partial pressure of nitrogen is asked, turning out to be 0.746 atm.

In such a case, we can start by looking at the provided table, which shows the composition of dry air in mass basis, which means we must convert the composition of nitrogen to mole fraction by knowing that the average molar mass of air is 28.9647 g/mol, and thus, we infer that the mole fraction of nitrogen in air is about 0.755 according to:

[tex]x_{N_2}=\frac{0.781*14.0067g/mol*2}{28.9647g/mol} =0.755[/tex]

Then, we recall the Dalton's law version that relates total pressure, partial pressure and mole fraction written for nitrogen:

[tex]P_{N_2}=x_{N_2}P[/tex]

Finally, we plug in the previously calculated mole fraction and the total pressure of air to obtain:

[tex]P_{N_2}=0.755*0.987 atm\\\\P_{N_2}=0.746atm[/tex]

Learn more:

Answer:

0.1 M

Explanation:

(25 mL) (0.20 M) / 50 mL = 0.1 M

It requires 60 mL of 0.20 M sodium hydroxide [tex](NaOH)[/tex] to neutralize 25 mL of carbonic acid [tex](H_2CO_3)[/tex], hence the carbonate ions concentration is [tex]0.24M[/tex].

Given:

Reaction:

[tex]\to \bold{2NaOH + H_2CO_3 \to Na_2CO_3 + 2H_20 }[/tex]

[tex]NaOH[/tex] volume [tex](V_B) = 60 \ ml[/tex]  

[tex]H_2CO_3[/tex] Volume [tex](V_A) = 25\ ml[/tex]  

[tex]NaOH[/tex] Molarity [tex](C_B) = 0.20\ M[/tex]

[tex]H_2CO_3[/tex] moles [tex](n_A) = 1[/tex]

[tex]NaOH[/tex] moles [tex](n_B) = 2[/tex]

To find:

[tex]H_2CO_3[/tex] Molarity [tex](C_A) =?[/tex]

Solution:

Using the neutralization reaction:  

[tex]\to \frac{C_AV_A}{C_BV_B} =\frac{n_A}{n_B} \\\\[/tex]

[tex]\to C_B = 0.2\ M \\\\ \to n_A = 1 \\\\ \to n_B = 2 \\\\ \to V_B = 60\ ml \\\\ \to V_A = 25\ ml[/tex]

Calculating the [tex]C_A[/tex]:

 [tex]\to \frac{C_A \times 25}{0.2 \times 60} =\frac{1}{2} \\\\\to C_A =\frac{1 \times 0.2 \times 60}{2 \times 25} \\\\\to C_A =\frac{1 \times 2 \times 12}{2 \times 5 \times 10} \\\\ \to C_A =\frac{ 12}{ 5 \times 10} \\\\\to C_A = \frac{6}{5 \times 5} \\\\\to C_A = \frac{6}{25} \\\\\to C_A=0.24\ M[/tex]

Therefore, the concentration of carbonic acid is "0.24M".

Learn more about the concentration:  

brainly.com/question/9889034

The concentration of carbonic acid( H₂CO₃) is 0.24 M.

The given reaction:

2 NaOH + H₂CO₃ → Na₂CO₃ + 2H₂O

Volume of NaOH  = 60mL

Volume of H₂CO₃ = 25 mL

Molarity of NaOH= 0.20M

To find:

Molarity of H₂CO₃=?

2 moles of NaOH and 1 mol of H₂CO₃ reacts to give 1 mol of Na₂CO₃.

Using the neutralization reaction:  

Consider A to be NaOH and B to be  H₂CO₃

[tex]\frac{\text{Number of moles of A}}{\text{Number of moles of B}} =\frac{\text{Molarity of A*Volume of A}}{\text{Molarity of B*Volume of B}}[/tex]

On substituting the values in order to calculate molarity of H₂CO₃:

[tex]\text{Molarity of B}=\frac{1*0.2*60}{2*25} \\\\\text{Molarity of B}=0.24M[/tex]

Therefore, the concentration of H₂CO₃ is 0.24 M.

Learn more:

brainly.com/question/19943363

Answer:

we do the best possible in our

Answer: Semiconductors

Explanation:

Answer:

A

Explanation:

I think it's the answer

a.

The atomic radius of iridium is 1.355 Å

For a face-centered cubic unit cell, with edge length, a and atomic radius r,

we have a² + a² = (4r)²

2a² = 16r²

r² = a²/8

r = a/√8

Since a = 3.833 Å,

Substituting this into the equation, we have

r = a/√8

r = 3.833 Å/√8

r = 3.833 Å/2.828

r = 1.355 Å

So, the atomic radius of iridium is 1.355 Å

b.

The density of iridium metal is 22.67 g/cm³

To find the density of the iridium metal, we need to find the mass of atoms per unit cell.

So, for the face centered cubic iridium atom, there are 6 faces per unit cell × 1/2 atoms per face + 4 corners per unit cell × 1/4 atoms per corner = 3 atoms + 1 atom = 4 atoms per unit cell.

So, the mass of the atoms in the unit cell is m = number of atoms/cell × number of moles/atom × molar mass of Iridium

= 4 atoms/cell × 1 mol/6.022 × 10²³ atoms × 192.22 g/mol

= 768.88/6.022 × 10²³ g/cell

= 127.68 × 10⁻²³ g/cell

= 1.2768 × 10⁻²¹ g/cell

Next, we need to find the volume of the unit cell which is V = a³

= (3.833 Å)³

= (3.833 × 10⁻¹⁰ m)³

= 56.314 × 10⁻³⁰ m

= 5.6314 × 10⁻²⁹ m

So, the density of iridium = mass of unit cell/volume of unit cell

= m/V

= 1.2768 × 10⁻²¹ g/cell ÷ 5.6314 × 10⁻²⁹ m

= 0.2267 × 10⁸ g/m³

= 0.2267 × 10⁸ g/m³ × 10⁻⁶ m³/cm³

= 0.2267 × 10² g/cm³

= 22.67 g/cm³

So, the density of iridium metal is 22.67 g/cm³

Learn more about face-centered cubic unit cell here:

https://brainly.com/question/17192154

Answer:

O it's not

Explanation:

Have a great day!

Molecules are formed when two or more atoms chemically bond together. In 3H₂(SO)₄, three molecules are present.

Molecules are the smallest unit present in any compound and are formed by a group of atoms. A number denoted in front of the chemical species is the coefficient that represents the number of molecules.

The coefficient present in front of the reactant or the product in a chemical reaction gives the number of the molecules present in a compound. As three is denoted in front of the sulphuric acid, hence will be the number of the molecules.

Therefore, there are three molecules present in sulphuric acid.

Learn more about molecules here:

https://brainly.com/question/22055640

#SPJ1

the release of energy

Answer:

pl

saponification palmitate

Answer: the answer is  b

Explanation:I took the test and got it

pls mark as brainliest if correct for you

Answer:

Hey mate.....

Explanation:

This is ur answer.....

A triple bond is made of two pi bonds and one sigma bond. Examples of compounds with triple bonds include nitrogen gas, the cyanide ion, acetylene and carbon monoxide.

Hope it helps!

Brainliest pls!

Follow me! :)

The intermolecular bonding for HF is van der Waals, whereas for HCL, the intermolecular bonding is hydrogen. Since the van der Waals bond is stronger than hydrogen, HF will have a higher boiling temperature. Since the covalent bond is stronger than van der Waals, HF will have a higher boiling temperature.

Answer:

cellular respiration

Explanation:

hope this helps :)

brainliest plzzzzzzz

Answer:

Ok the poprtion would look like this :  x                   23  

                                                          -----------   =     ----------

                                                            230                 100

Explanation:

So for the last fill in it could be 52.9 or 60

i hope i got it correct lol pretty sure i did

When perfume or cologne is sprayed into the air, it turns into a gas and its particles mix with other air particles that quickly move around the room. This is because gas is the least dense of the three states of matter. It moves quickly into any space or volume because it has the least density. This is called diffusion, when molecules or particles move from areas with high concentration to low concentration areas. 

Answer:

[tex]FeCl_{2} +H_{2} S->FeS + 2HCl[/tex]

Explanation:

I am assuming that we have to balance this equation. On the left side, we have one Fe, 2 H, 2 Cl, and 1 S. On the right side, we have 1 Fe, 1 H, 1 Cl, and 1 S. Adding a 2 as a coefficient in front of the HCl on the right side will make 2 H and 2 Cl instead, balancing the overall equation.

FeCl_{2} +H_{2} S- > FeS + 2HClFeCl 2 +H 2 S−>FeS+2HCl

Answer:

a hydrogen atom contains only one proton in it's nucleus, while atoms of all other elements contain more than one proton

Brainliest plzz

Answer:

In the picture A kettle is boiling water and evaporating it we can see the water vapours coming out of the kettle and there is a paper on top of the kettle from where the water vapours are coming out .

Explanation:

is this right ?? i hope it helps

The statement is true in this situation is C. The size of Ffric is the same as the size of Fapp:

From the diagram, since the body is in equilibrium, the sum of vertical forces equals zero. Also, the sum of horizontal forces equal zero.

So, ∑Fx = 0 and ∑Fy = 0

Since Fapp acts in the negative x - direction and Ffric acts in the positive x - direction,

∑Fx = -Fapp + Ffric = 0

-Fapp + Ffric = 0

Fapp = Ffric

Also, since Fgrav acts in the negative y - direction and Fnorm acts in the positive y - direction,

∑Fy = Fnorm + (-Fgrav) = 0

Fnorm - Fgrav = 0

Fnorm = Fgrav

So, we see that the size of Fapp equals size of Ffric and the size of Fnorm equals the size of Fgrav.

So, the correct option is C

The statement which is true in this situation is C. The size of Ffric is the same as the size of Fapp.

Learn more about equilibrium of forces here:

https://brainly.com/question/12980489

Answer:

it's a chemistry change

Explanation:

this is because heat is causing permanent changes and can no longer be changed back to its original atate

Answer:

4 meters

Explanation:

4 centimeters and millimeters are too small, while 4 kilometers is too large.