Write the empirical formula for at least four ionic compounds that could be formed from the following ions: NO3, Pb^4+, NH4, SO4

Which of the following statements best explains the trends in boiling points?

A. The atomic size increases down the group, and this decreases the strength of the intermolecular forces.

                                           A is incorrect

B. The total number of electrons decreases down the group, and this decreases the strength of the intermolecular forces.

                                            B is incorrect

C. The total number of electrons increases down the group, and this increases the strength of the intermolecular forces.

                                             C is correct

D. The chances of forming a permanent dipole increases down the group, and this increases the strength of the intermolecular forces.

                                              D is incorrect

The boiling point increase down a group because the total number of electrons increases down the group, and this increases the strength of the intermolecular forces. Hence option C is correct.

Boiling point of a substance is the temperature at which the substance changes from its liquid state to vapour state. Boiling point of a molecule or compounds depends on the bond type, molecular weight, temperature and pressure.

For ionic compounds, boiling point will be higher since ionic bonds are stronger than covalent compounds. There is a periodic trend for the physical properties such as boiling point for elements in periodic table.

Down a group, the number of electrons increases and the atomic size also as well as the ionic character increases down a group . These two facts leads to higher intermolecular attraction, thus more temperature have to applied to weaken the bonds.

Higher temperature to be applied means the boiling point of the substance is higher. Therefore, boiling point down a group increases because of the higher intermolecular attraction as said in option C.

To find more about boiling point, refer the link below:

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Answer:

-1

Explanation:

Answer:

The blue star is the hottest star.

Explanation:

Red stars are cooler than the sun, with surface temperatures of 3,500 K for a bright red star and 2,500 K for a dark red star. The hottest stars are blue, with their surface temperatures falling anywhere between 10,000 K and 50,000 K

Answer:

False  grams is not used

Explanation:

IDEAL GAS LAW

The ideal gas law states that PV = NkT, where P is the absolute pressure of a gas, V is the volume it occupies, N is the number of atoms and molecules in the gas, and T is its absolute temperature.  

It is necessary to use Kelvin for the temperature and it is conventional to use the SI unit of liters for the volume. However, pressure is commonly measured in one of three units:  kPa ,  atm , or  mmHg . Therefore,  R  can have three different values.

Answer:

If a body is accelerated by 10m/s^2, it means that the body's speed (or velocity to be precise) is increasing by 10m/s every second. That is, if the initial ...

Explanation:

a) m (metre)

b) mm (millimeter)

Hope my answer is helpful to you ☺️

Answer:

An endothermic reaction is when heat is needed by the reaction, so it draws heat from its surroundings, making them feel cold. Just like a ice pack.

Answer:

option b

Explanation:

answer from gauth math

Answer:

AgNo3+Mgcl2--->Agcl2+Mg(No3)2

I hope this helps

the universe formed through the big bang explosion, all of the elements on Earth have been cooked for billions of years in stars and then released in the universe through super- nova explosions.

Burning a sugar cube is a chemical change. Fire activates a chemical reaction between sugar and oxygen. The oxygen in the air reacts with the sugar and the chemical bonds are broken. Burning sugar leads to reaction of sugar with oxygen in air and leads to formation of carbon dioxide and water. The change is irreversible and is thus a chemical change

Answer:

0.19875

Explanation:

nFe2O3=0.099375

nFe=2nFe2O3=0.19875

Answer:

you have to use the avogadro's constant of 6.023×10^23 to calculate the number of molecules of carbon dioxide.and you also have to use the molecular mass which is 44.

35.5/44×6.023×10^23

=4.85×10^23

I hope this helps and sorry if it's wrong

Answer:

Pressure on Surface A > Pressure on Surface B

Explanation:

Pressu

re on Surface B > Pressure on Surface A

Answer:

The molar mass of gas Q is 43.923 g/mol

Explanation:

The given volume of ethane gas that diffuses through a porous plug in 100 seconds = 100 cm³

Therefore;

The rate of diffusion of ethane gas through the porous plug, [tex]v_{ethane}[/tex], is given as follows;

[tex]v_{ethane}[/tex] = (100 cm³/100 s) = 1 cm³/s

The molar mass of ethane, C₂H₆ = 2×12 g/mol + 6×1 g/mol = 30 g/mol

The given volume of gas, Q, that diffuses through a porous plug in 121 seconds = 100 cm³

∴ The rate of diffusion of the gas, Q, [tex]v_Q[/tex] = 100/121 cm³/s

Graham's Law of diffusion states that the rate of diffusion of a gas is inversely proportional to the square root of the molecular mass of the gas

Mathematically, we have;

[tex]\dfrac{v_A}{v_B} =\sqrt{\dfrac{m_B}{m_A} }[/tex]

Where;

[tex]v_A[/tex] = The rate of diffusion of gas A

[tex]v_B[/tex] = The rate of diffusion of gas B

[tex]m_A[/tex] = The molar mass of the gas A

[tex]m_B[/tex] = The molar mass of the gas B

Therefore, for ethane and gas Q, measured under the same condition, we have;

[tex]\dfrac{v_{ethane}}{v_Q} =\sqrt{\dfrac{m_Q}{m_{ethane}} }[/tex]

[tex]\dfrac{1 \ cm^3/s}{\dfrac{100}{121} \ cm^3/s} =\sqrt{\dfrac{m_Q}{30 \ g/mol} }[/tex]

[tex]m_Q = \left ({\dfrac{121}{100} } \right) ^2 \times 30 \ g/mol = 43.923 \ g/mol[/tex]

The molar mass of gas Q, [tex]m_Q[/tex] = 43.923 g/mol.

Answer:

Explanation:

D = mass/volume.

for the units, I'll take it in g/L but I don't know which units you want.

4.44*10^5 mg =  0.444 grams.

0.444/7 = 0.0634 g/L

C.

This is basically the definition of percent composition which is how much mass a element contributes to a specific molecule.

Answer: B.

Explanation:

the relative amount of mass an atom contributes to a molecule

Answer:

In atomic physics and quantum chemistry, the electron configuration is the distribution of electrons of an atom or molecule in atomic or molecular orbitals.

Answer:

don't know

Explanation:

try it your self

try it your self

try it your self

try it your self

try it your self

try it your self

Answer:

K°(g)* + 419 Kj/mole => K⁺(g) + e⁻

Explanation:

1st ionization step for potassium is the ionization of the 4s¹ electron. This requires 419 Kj/mole energy (endothermic). The reaction equation is ...

K°(g)* + 419 Kj/mole => K⁺(g) + e⁻

*note: Ionization of group IA metals requires they be in gas phase. That is, as shown by the Born-Haber Cycle** for formation of ionic compounds ...

K°(s) + 89.24 Kj/mole => K°(g); then ...

K°(g) + 419 Kj/mole => K⁺(g).

**Recommend review of Born-Haber cycle for formation of ionic compounds.

Answer:

62.5 moles of O₂.

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

2C₈H₁₈ + 25O₂ —> 16CO₂ + 18H₂O

From the balanced equation above,

2 moles of C₈H₁₈ reacted with 25 moles of O₂.

Finally, we shall determine the number of mole of O₂ needed to react with 5 moles of C₈H₁₈. This can be obtained as shown below:

From the balanced equation above,

2 moles of C₈H₁₈ reacted with 25 moles of O₂.

Therefore, 5 moles of C₈H₁₈ will react with = (5 × 25) / 2 = 62.5 moles of O₂.

Thus, 62.5 moles of O₂ is needed for the reaction.

Answer:

Answer: Atoms of chlorine (CI) and magnesium (Mg)

Answer: Atoms of chlorine (CI) and magnesium (Mg)is your answer

Answer:c

Explanation:

Answer: C

i think none of these

Explanation:

Answer:

C. Lithium

Explanation:

This image describes the trend in reactivity. Group 1 metals are always the most reactive so yeah :)

Answer:

The answer for ka is 5.26x10^-5

Explanation:

Fill in 5.26x10^-5