Calculate the number of vacancies in gold per cubic centimeter at 1000 K, where the density and atomic weight for gold at are 18.63 g/cm3 and 196.9 g/mol, respectively, at 1000 K. The energy for vacancy formation in gold is 0.98 eV / atom. (Please express scientific notation using E to indicate the exponent - for example, 2.5E3

Answer: 20.775 g S

Explanation: 3.9x10^23 atoms = 0.648 mol

Atomic mass S = 32.08

S in grams = 20.775

Answer:

1.0 × 10⁸ ruthenium atoms

Explanation:

Step 1: Calculate the diameter (d) of an atom of ruthenium

The diameter of an atom is twice its radius.

d = 2 × r = 2 x 178 pm = 356 pm

Step 2: Convert "d" to meters

We will use the conversion factor 1 m = 10¹² pm.

356 pm × 1 m/10¹² pm = 3.56 × 10⁻¹⁰ m

Step 3: Convert the distance of the tip of a finger (D) to meters

We will use the conversion factor 1 m = 10² cm.

3.6 cm × 1 m/10² cm = 0.036 m

Step 4: Calculate the number of atoms of ruthenium required

We will use the following expression.

D/d = 0.036 m/3.56 × 10⁻¹⁰ m = 1.0 × 10⁸

The image having the complete question is attached to this answer.

Answer:

Ga

Explanation:

In order to answer this question well, we must have a good enough knowledge of the periodic table.

We know that the elements in group 3A or group 13 of the periodic table have three valence electrons in their outermost shell.

We just have to look out among the options to notice if there is any member of group 3A or 13.

Gallium is a member of this group. Hence the answer above.

Answer:

A4

B1

C3

D2

Explanation:

A4: dispersion forces occur in everything as it is variations in the electron cloud.  They are very weak and are the only intermolecular force in a non-polar molecule such as CH4.

B1: Dipole Dipole forces occur between polar molecules.  The polarity of the molecule creates a dipole which can attract each other.  they are stronger then dispersion forces.  CBr2Cl2 is a polar molecule.

C3: hydrogen bonding is a special type of dipole-dipole force and are pretty strong.  They can only occur between H-N, H-O, and H-F bonds. NH3 has N-H bonds.

D2: ion dipole forces occur between a polar molecule and ions.  They mainly occur when charged species (ions) are in a polar solvent but there are likely less common examples.

I hope this helps.  Let me know if anything is unclear.

Answer:

Mass of Cl₂  = 887.5 g

Mass of Na = 575 g

Explanation:

Given data;

Number of moles of sodium chloride produced = 25.0 mol

Mass of Na required = ?

Mass of Cl₂ required = ?

Solution:

Chemical equation:

2Na  +   Cl₂    →      2NaCl

now we will compare the moles of sodium chloride with both reactant.

                      NaCl         :          Na

                         2            :           2

                      25.0         :         25.0

                    NaCl          :          Cl₂

                       2             :           1

                      25.0        :          1/2 ×25.0 = 12.5 mol

Mass of Na:

Mass = number of moles × molar mass

Mass = 25.0 mol × 23 g/mol

Mass = 575 g

Mass of Cl₂:

Mass = number of moles × molar mass

Mass = 12.5 mol × 71 g/mol

Mass = 887.5 g

Answer:

0.13M and 0.16m.

Explanation:

Molarity is defined as the moles of solute present in 1L of solution.

Molality is the moles of solute per kg of solvent.

To solve this problem we need to convert the mass of sucrose to moles using its molar mass and finding the volume in L of the solution and the mass in kg of solvent:

Moles sucrose:

Molar mass:

12C = 12*12.01g/mol = 144.12g/mol

22H = 22*1.005g/mol = 22.11g/mol

11O = 11*16g/mol = 176g/mol

Molar mass of sucrose is 144.12g/mol + 22.11g/mol + 176g/mol = 342.23g/mol

Moles are:

19.0g * (1mol / 342.23g/mol) = 0.0555 moles of sucrose

Liters solution:

425mL * (1L / 1000mL) = 0.425L

kg solvent:

425mL * (0.82g/mol) = 348.5g * (1kg / 1000g) = 0.3485kg

Molarity:

0.0555 moles / 0.425L

Molality:

0.0555 moles / 0.3485kg

Answer:

B. Fluorine (F) element easily gains one electron to for a negative ion.

Howmuch woodwouldawoodchuckchuckifawoodchuckcouldchuckwoodwoodchuckcouldchuckwoodwoodchuck

Answer:

7 bcs atomic number of atom is its number of proton.

hope it helps.

Answer: Mendeleev's periodic law : The properties of element are a periodic function of the atomic masses . Limitations:-(1)positions of hydrogen is not correctly placed. (2) The positions of isotopes could not be explained . For ex:- cl35 are cl37 are placed in the same group.

Explanation:

Answer:

The higher up an object is the greater its gravitational potential energy. ... As most of this GPE gets changed into kinetic energy, the higher up the object starts from the faster it will be falling when it hits the ground. So a change in gravitational potential energy depends on the height an object moves through.

Answer:

The 3rd one " C " because it surrounds the nucleus it's not known the inside

An electron is found in the space surrounding the nucleus.

An electron is a sub-atomic particle which is found in the extra-nuclear part of an atom. They are found revolving int the shells which surround the nucleus.It carries a negative charge of  minus 1 .

They are the elementary particles as they do not  have known components or structure. It has a mass which is approximately equal 1/1836 th that of proton.No two electrons can occupy the same  quantum state according to the Pauli exclusion principle.

As all elementary particles, it too does possess both particle and wave characteristics. They can collide with each other and cause diffraction . Wave properties of electrons are easier to observe  with aid of experiments, because of lower mass and longer de Broglie wavelength.

Learn more about electrons, here:

https://brainly.com/question/2845051

#SPJ2

Answer:

See explanation and image attached

Explanation:

We know that some substituted benzene reacts faster than benzene towards electrophillic substitution. This is often due to the activation of the benzene ring towards electrophillic substitution by resonance.

-OCH3 directs an incoming electrophile (such as during bromination) to the ortho or para position. This is made possible by resonance (mesomeric) effect as shown in the image attached to this answer.

Image credit: pinterest

Answer:Option (b) is the correct answer.

Explanation:

When a neutral element loses an electron then it acquires a positive charge and it is known as a cation.

For example, when a neutral iron atom loses three electrons then it forms a  ion.

On the other hand, when a neutral element gains an electron then it acquires a negative charge and it is known as a anion.

For example, a sulfate ion means  ion.

Thus, we can conclude that out of the given options sulfate is not a cation.

Explanation:

Answer:

In order to create a Bohr model for carbon, you must start in the first shell of electrons. The first shell can hold up to 2 of carbons 6 electrons. After filling up the first shell you can move on to the second that can hold up to 8 electrons. The finished Bohr model would have 2 electrons in the first shell and 4 in the second shell.

Explanation:

Answer:

elemnt b

Explanation:

Answer:

(a) 0.135 nm; 135 pm

(b) 3.70 × 10⁶ Au atoms

Explanation:

The radius of an atom of gold (Au) is about 1.35 A. (a) Express this distance in nanometers (nm) and in picometers (pm). (b) How many gold atoms would have to be lined up to span 1.0 mm.

(a)

Step 1: Convert the radius to meters

We will use the conversion factor 1 m = 10¹⁰ A.

1.35 A × 1 m/10¹⁰ A = 1.35 × 10⁻¹⁰ m

Step 2: Convert the radius from m to nm

We will use the conversion factor 1 m = 10⁹ nm.

1.35 × 10⁻¹⁰ m × 10⁹ nm/1 m = 0.135 nm

Step 3: Convert the radius from m to pm

We will use the conversion factor 1 m = 10¹² pm.

1.35 × 10⁻¹⁰ m × 10¹² pm/1 m = 135 pm

(b)

Step 1: Convert "1.0 mm" to meters

We will use the conversion factor 1 m = 10³ mm.

1.0 mm × 1 m/10³ mm = 1.0 × 10⁻³ m

Step 2: Calculate how many gold atoms would have to be lined up to span 1.0 × 10⁻³ m

We will divide 1.0 × 10⁻³ m by 2 times the radius (diameter) of an atom of gold.

1.0 × 10⁻³ m / (2 × 1.35 × 10⁻¹⁰ m) = 3.70 × 10⁶

Answer:

5.14 * 10^24 molecules H2O

Explanation:

8.54 moles of H2O contains 8.54 x 6.022 x 10^23 = 5.14 x 10^24 molecules of H2O.

Answer:

K < Si < O < H

Explanation:

The ionization energy is regarded to be the amount of energy required to remove an electron in an atom from its ground state. The factor that determines the Ionization energy atomic radius. This is because the larger the atomic radius, the smaller the Ionization energy because of the shielding effect or screening effect of the inner shell electrons.  Across the period, the ionization energy increases progressively from left to right due to decreasing atomic radii caused by the increased nuclear charge. Also, down the period the ionization energy decreases because of increasing atomic radii and increasing shielding effect or screening effect of the inner shell electrons.

So, the increasing order of Ionization energy of the given elements are:

K < Si < O < H

Answer:

When it is absorbed, it is converted into heat energy, and the object heats up.

Explanation:

When the photon is absorbed, it is released as heat energy.

Answer:

A. A solid mixture is heated. One component transitions directly between solid and gas ---> Sublimation

B. A liquid is carefully poured out, leaving the solid behind in the container ----> Decantation

C. A solvent is added to dissolve only one mixture component and then the liquids are separated ----> solvent extraction

D. A solid is caught on paper or a membrane while the liquid passes through ---> Filtration using filter paper

Explanation:

A. Sublimation is a process of separating solids which sublimes (solids turning directly to gases) from a a mixture of other solids which do not sublime. When the mixture is heated, the solids which sublime are separated and those which do not are left behind. examples of solids which sublime are naphthalene, Iodine crystals, etc.

B. Decantation is the process of carefully pouring out a liquid from a mixture of it with a solid, leaving the solid behind. Example, a mixture of sand and water where water can be easily decanted, leaving the sand behind.

C. In the process of solvent extraction, a mixture of solids which are soluble in different solvent, one of the components is dissolved in a solvent in which it is soluble while the others are not. The solution is then filtered out and the solid is then separated from the solvent by evaporation.

D. In filtration using a filter paper, the solid-liquid mixture is passed through a filter paper which has pores the size through which liquids can pass through but the solid can not. therefore, the solid remains behind on the paper while the liquid passes through.

A is sublimation, B is decantation, C is solvent extraction, and D is filtration.

Chemical mixtures are separated in different ways.

More on separation of mixtures can be found here: https://brainly.com/question/863988

hope it's helpful

Explanation:

its is classified as ionic cyrstal

Answer:

For question 15, we use cloths, heat-resistant gloves. (From what I know, I am just a 7th grader. Forgive me.)

For question 16, we use bowls to drink soup, metal cans which we use to drink soda from, we use lunch boxes which are insulated or thermos can be used for bringing to school to eat lunch and keeping food warm, we use aluminium foil containers to keep food warm.

For question 17, I think it's related to chart above question 15 and etc, if it isn't then I don't think I may be able to help.

Answer:

8.6 mol

Explanation:

number of moles = molar concentration x volume in litre

number of moles = 2.33 M x 3.70 L = 8.6 mol

Answer:

64

Explanation:

mass number =proton + neutron

=30+34=64

Answer: A = atomic number = 12

Explanation: A (atomic number) defines the chemical element. It is the numbervof protons or electrons. Neutron numbers may vary, produving isotopes of differing atomic mass. This isotope has atomic mass 28. The atomic number 12 = carbon. C28 does not really exist. If it could be produced it would be radioactive with an almost zero halflife.

x = 10, y = 20/6

Given

one number is three times of the other

their arithmetic mean is 10

Required

The numbers

Solution

Suppose the numbers you are looking for are x and y, then :

x = 3y (equation 1)

The arithmetic mean : the average of values

(x+3y)/2=10

x+3y = 20 (equation 2)

Substitute equation 1 into equation 2

3y+3y=20

6y=20

y = 20/6

from equation 1 :

x= 3 x 20/6

x = 60/6

x = 10

Answer:

The formula of the magnesium halide is MgF₂

Explanation:

All halides, X, produce a salt with Mg with the formula:

MgX₂

-There are 2 moles of the halide ion per mole of Mg-

With the mass of the MgSO₄ we can find moles of magnesium sulfate  = Moles Mg.

With moles of Mg we can know the moles of the halide -1 mole Mg = 2 moles of Halide-

And we can find the mass of Mg in the 0.0776g sample. Subtracting we can find the mass of the halide and, with the mass and moles of the halide we can find its molecular weight and its identity:

Moles MgSO₄ -Molar mass: 120.366g/mol- = Moles Mg:

0.150g * (1mol / 120.366g) = 1.2462x10⁻³ moles Mg

Moles halide:

1.2462x10⁻³ moles Mg * 2 = 2.4924x10⁻³ moles Halide

Mass Mg -Molar mass: 24.305g/mol:

1.2462x10⁻³ moles Mg * (24.305g / mol) = 0.0303g Mg

Mass halide:

0.0776g - 0.0303g Mg = 0.0473g

Molecular weight of the halide:

0.0473g / 2.4924x10⁻³ moles =

18.98g/mol

This molecular weight is the molecular weight of Fluoride ion, F⁻,

Answer

Cold Climates

Explanation:

It can go slow