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3 years ago

What is an atomic nucleus

Chemistry

2 answers:

kakasveta [241]3 years ago

5 0

Answer:

The atomic nucleus is the small, dense region consisting of protons and net at the center of an atom.

Explanation:

The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment. ... Protons and neutrons are bound together to form a nucleus by the nuclear force.

bearhunter [10]3 years ago

5 0

Answer:

The atomic nucleus is the small , dense region consisting of protons and neutrons at the center of an atom .

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Answer the question briefly: How can atom collapse and why are atoms stable?

kykrilka [37]

The nuclei of atoms become unstable when the repelling forces of the protons cannot be balanced by the number of neutrons in the nucleus. It then re-arranges itself randomly to a more stable configuration by emitting any of a series of particles. During radioactive decay, an atom does not collapse.

Since an atom is mostly empty space - that is it’s nucleus is relatively distant from the electron shells so, in the presence of extreme forces such as gravity inthe collapse of a large star, the inward pressures on the atom overcome the natural balance of the atomic structure and the ‘empty space’ disappears as nuclei are mashed together by the intense pressures and a neutron star is formed. Under even more external pressure, even the neutron star can collapse to form a black hole.

8 0

3 years ago

What is the overall energy transformation in a coal-fired power plant?.

polet [3.4K]

Answer: When coal is burned, chemical potential energy is transformed into thermal energy, light energy, and sound energy. Only the thermal energy is used for electricity production. Light and sound energy dissipate into the environment, immediately reducing efficiency.

Hope this helps.

7 0

2 years ago

Propane is often used to heat homes. The combustion of propane follows the following reaction: C3H8(g) + 5O2(g)  3CO2 (g) + 4H

swat32

Answer:

To release 7563 kJ of heat, we need to burn 163.17 grams of propane

Explanation:

Step 1: Data given

C3H8 + 5O2 -----------> 3CO2 + 4H2O ΔH° = –2044 kJ

This means every mole C3H8

Every mole of C3H8 produces 2044 kJ of heat when it burns (ΔH° is negative because it's an exothermic reaction)

Step 2: Calculate the number of moles to produce 7563 kJ of heat

1 mol = 2044 kJ

x mol = 7563 kJ

x = 7563/2044 = 3.70 moles

To produce 7563 kJ of heat we have to burn 3.70 moles of C3H8

Step 3: Calculate mass of propane

Mass propane = moles * Molar mass

Mass propane = 3.70 moles * 44.1 g/mol

Mass propane = 163.17 grams

To release 7563 kJ of heat, we need to burn 163.17 grams of propane

7 0

3 years ago

An ionic bond forms when atoms blank electrons

8_murik_8 [283]

Answer:

An ionic bond forms when atoms transfer electrons.

Explanation:

Ionic bonds are formed when atoms transfer electrons. (In contrast, covalent bonds are formed when atoms share electrons.)

There's a distinction between the two: when two atoms react to form an ionic bond, one atom would completely lose one electron, while the other would completely gain that electron. The atom that loses the electron becomes a positively-charged ion called a cation, whereas the atom that gains the electron becomes a negatively-charged ion called an anion.

For example, consider the reaction between a sodium $\rm Na$ atom and a chlorine $\rm Cl$ atom: $\rm Na + Cl \to NaCl$ .

When the sodium atom and the chlorine atom encounter, the sodium atom would lose one electron to form a positively-charged sodium ion, $\rm Na^{+}$ . The chlorine atom would gain that electron to form a negatively-charged chlorine ion $\rm Cl^{-}$ .

These two ions will readily attract each other because of the opposite electrostatic charges on them. This electrostatic attraction (between two ions of opposite charges) is an ionic bond.

Overall, it would appear as if the sodium $\rm Na$ atom transferred an electron to the chlorine $\rm Cl$ atom to form an ionic bond.

In contrast, when two atoms react to form a covalent bond, they share electrons without giving any away completely. Therefore, it is possible to break certain covalent bonds apart (using a beam of laser, for example) and obtain neutral atoms.

On the other hand, when an ionic bond was broken, the result would be two charged ions- not necessarily two neutral atoms. The electron transfer could not be reversed by simply breaking the bond.

For example, when table salt $\rm NaCl$ is melted (at a very high temperature,) the ionic bond between the sodium ions and chloride ions would (mostly) be broken. However, doing so would only generate a mixture of $\rm Na^{+}$ and $\rm Cl^{-}$ ions- not sodium and chlorine atoms.

7 0

2 years ago

What is the longest wavelength in the Balmer series? (Hint: the Rydberg constant for Hydrogen is 1.096776×107 1/m, and the Balme

boyakko [2]

Answer: The longest wavelength of light is 656.5 nm

Explanation:

For the longest wavelength, the transition should be from n to n+1, where: n = lower energy level

To calculate the wavelength of light, we use Rydberg's Equation:

$\frac{1}{\lambda}=R_H\left(\frac{1}{n_i^2}-\frac{1}{n_f^2} \right )$

Where,

$\lambda$ = Wavelength of radiation

$R_H$ = Rydberg's Constant = $1.096776\times 10^7m^{-1}$

$n_f$ = Higher energy level = $n_i+1=(2+1)=3$

$n_i$ = Lower energy level = 2 (Balmer series)

Putting the values in above equation, we get:

$\frac{1}{\lambda }=1.096776\times 10^7m^{-1}\left(\frac{1}{2^2}-\frac{1}{3^2} \right )\\\\\lambda =\frac{1}{1.5233\times 10^6m^{-1}}=6.565\times 10^{-7}m$

Converting this into nanometers, we use the conversion factor:

$1m=10^9nm$

So, $6.565\times 10^{-7}m\times (\frac{10^9nm}{1m})=656.5nm$

Hence, the longest wavelength of light is 656.5 nm

4 0

3 years ago