CHEMISTRY HIGH SCHOOL

Calculate the number of atoms in 4g of bromine molecule.(Br).(avogadro 's constant =6.02 x 10²³ mol-¹; Br=80)

Answers

Answer 1

Answer:

Answer:

$\n N=n * N_(A)$

We do not have $n$ - the amount of substance.

$n=(m)/(M)\n$

The molecular weight ( $M$ ) of Bromine is 80.

$n=(4)/(80) = 0.05 \text{ mol}$

$N = 0.05 * 6.02 * 10^(23) = 0.301 * 10^(23)$

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The crystal lattice structure of ionic compounds is responsible for which set of characteristic properties?

Answers

Answer:

The characteristic properties are hard and brittle solids having high melting and boiling point

Explanation:

Ionic compounds are the type of chemical compounds that are formed by ionic bonding. An ionic compound is composed of two oppositely charged ions that are held together by electrostatic forces of attraction.

They are solids at room temperature and usually have a crystalline structure and have high melting and boiling point. Ionic compounds are hard but also brittle.

If your using Plato the answer is E.

Which subatomic particles orbit the nucleus

Answers

the answer is electrons

Electrons are that sub-atomic particles

when 200 grams of water cools from 50 c to 25 c the total amount of heat energy released by the water is?

Answers

Answer : The heat released by the eater is, $2.1* 10^4J$ [/tex]

Explanation :

Formula used :

$Q=m* c* \Delta T$

or,

$Q=m* c* (T_2-T_1)$

where,

Q = heat released = ?

m = mass of water = 200 g

c = specific heat of water = $4.184J/g^oC$

$T_1$ = initial temperature = $50^oC$

$T_2$ = final temperature = $25^oC$

Now put all the given value in the above formula, we get:

$Q=200g* 4.184J/g^oC* (25-50)^oC$

$Q=20920J=2.1* 10^4J$ [/tex]

Therefore, the heat released by the eater is, $2.1* 10^4J$ [/tex]

Specific Heat:
Heat Energy= Mass of substance X Specific Heat X Change in Temp.
1. change in temp |50-25| = 25
2. specific heat of Water(H2O) = cal/g (Celsius) 1.000
heat energy= 200g X 1.000 X 25
Heat energy = 5000cal

When compared with the energy of an electron in the first shell of a carbon atom, the energy of an electron in the second shell of a carbon atom is(1) less(2) greater(3) the same

Answers

When compared with the energy of an electron in the first shell of a carbon atom, the energy of an electron in the second shell of a carbon atom is $\boxed{\left( {\text{2}} \right){\text{ greater}}}$ .

Further explanation:

Quantum numbers:

Quantum numbers govern the size, energy, shape, and orientation of an orbital. The four quantum numbers are as follows:

1. Principal Quantum Number (n): It denotes the principle electron shell. The values of n are positive integers (1, 2, 3,…).

2. Angular Momentum Quantum Number (l): It represents the shape of an orbital. The value of l is an integer from 0 to (n-1).

3. Magnetic Quantum Number $\left( {{m_l}} \right)$ : This quantum number represents the orientation of the orbital in space. The value of ${m_l}$ lies between –l to +l. The formula to calculate the value of ${m_l}$ is as follows:

${m_l} = - l,( - l + 1),.....,0,1,2,.....,(l - 1),l$

Therefore, the total number of ${m_l}$ values for a given value of l is 2l+1.

4. Electron Spin Quantum Number $({m_s})$ : It represents the direction of the electron spin. Its value can be $+ (1)/(2)$ or $- (1)/(2)$ .

The formula to calculate the energy of an electron in an atom is as follows:

${{\text{E}}_{\text{n}}} = \frac{{ - 13.6{{\text{Z}}^2}}}{{{{\text{n}}^{\text{2}}}}}{\text{eV}}$ …… (1)

Here,

E is the energy of an electron.

Z is the atomic number of atom.

n is the principal quantum number.

Calculation of energy of an electron in the first shell of carbon atom.

The value of Z is 6.

The value of n is 1.

Substitute these values in equation (1) to calculate the energy of electron in the first shell.

$\begin{aligned}{{\text{E}}_2}&=\frac{{ - 13.6{{\left( 6 \right)}^2}}}{{{{\left( 1 \right)}^{\text{2}}}}}{\text{eV}}\n&=\boxed{-489.6\;{\text{eV}}}\n\end{aligned}$

Calculation of energy of an electron in the second shell of carbon atom.

The value of Z is 6.

The value of n is 2.

Substitute these values in equation (1) to calculate the energy of an electron in the second shell.

$\begin{aligned}{{\text{E}}_1}&=\frac{{-13.6{{\left( 6 \right)}^2}}}{{{{\left( 2 \right)}^{\text{2}}}}}{\text{eV}\n&=\boxed{-122.{\text{4 eV}}}\n\end{aligned}$

The negative sign in the energy of the electron in both the shells indicates that the electron is bound to the nucleus of an atom. So the energy of electron in the second shell of carbon atom is greater than its energy in the first shell of carbon atom and therefore option (2) is correct.

Learn more:

1. Which transition is associated with the greatest energy change? brainly.com/question/1594022

2. Describe the spectrum of elemental hydrogen gas: brainly.com/question/6255073

Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Atomic structure

Keywords: energy of electron, n^2, Z^2, -13.6, n, Z, -122.4 eV, -489.6 eV, 6, 1, 2, first shell, second shell.

The answer is (2) greater. The energy of an electron will increase when the number of valence shell increases. So the energy of an electron in the second shell of a carbon atom is greater than in the first shell.

What is the difference between an atom in the ground state and an atom in an excited state? A. The atom in the ground state has less energy and is less stable than the atom in an excited state. B. The atom in an excited state has one fewer electron than the atom in the ground state. C. The atom in an excited state has more energy and is less stable than the atom in the ground state. D. The atom in an excited state has one more electron than the atom in the ground state.

Answers

The correct option is C.

An atom can be either in the ground state or in an excited state. An atom is said to be in the ground state, if the total energy of its electron can not be lowered by moving one or more electrons into different orbitals. At the ground state, the electrons in the atom have the lowest energy possible and they are stable. On the other hand, an atom is said to be in an excited state, if the energy of its electrons can be lowered by transferring one or more electrons into different orbitals. An atom in an excited state has more energy and is less stable.

The difference between an atom in the ground state and an atom in an excited state is being revealed by the third option C. The atom in an excited state has more energy and is less stable than the atom in the ground state.

Which of the following is NOT a pure substance?a. solution
b. element
c. molecule
d. compound

Answers

Answer:

A) Solution

Explanation:

Final answer:

A solution is not a pure substance, while elements, molecules, and compounds are examples of pure substances. The correct option is A.

Explanation:

The correct answer is a. solution. A solution is a mixture of two or more substances, so it is not a pure substance. Examples of solutions include saltwater and sugar water. On the other hand, elements, molecules, and compounds are all examples of pure substances. An element is a substance that cannot be broken down into simpler substances, such as gold or oxygen. A molecule is a combination of two or more atoms held together by chemical bonds, like water (H₂O) or carbon dioxide (CO₂). Lastly, a compound is a substance made up of two or more different elements chemically bonded together, like table salt (NaCl) or water (H₂O).