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3 years ago

Describe the nuclear model of the atom

1 answer:

7 0

An atom consist of mainly two parts, namely nucleus and electrons. In the nucleus, there are groups of protons and neutron DENSELY packed, each element has its own atomic number(number of protons) but can have different no. of neutron (isotop). within the proton and neutron, there are subatomic particles called quarks. Talking about the electrons, they move very quickly arround the nucleus and there are different energy level for electron to switch between. In chemical reaction, we are only concerning the no. of valence electrons.
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Which equilibrium system has HCO3- acting as a Brønsted-Lowry base?

IrinaVladis [17]

A Brønsted-Lowry base is a base is a proton acceptor.

In the only case where this is done is when HCO3- accepts a proton and becomes H2CO3.

In the other cases, HCO3- is donating a proton which makes it an acid.

8 0

3 years ago

Ultraviolet radiation and radiation of shorter wavelengths can damage biological molecules because they carry enough energy to b

Alja [10]

Answer:

439.7nm

Explanation:

Energy of a quantum can be calculated using below formula

E=hv...........eqn(1)

But v=λ/ c .........eqn(2)

If we substitute eqn(2) into eqn(1) we have

E= hc/(λ)

Where E= energy

h= Plank's constant= 6.62607004 × 10-34 m2 kg / s

c= speed of light

c= 2.998 × 10^8 m/s

λ= wavelength= ?

But the energy was given in Kj , it must be converted to Kj/ photon for unit consistency.

Energy E= 272 kJ/mol × 1mol/6.02× 10^23

Energy= 451.83× 10^-24 Kj/ photon

E= hc/(λ)...........eqn(1)

If we make λ subject of the formula

λ= hc/E

Then substitute the values we have

λ= [(6.626 × 10^-34) × (2.998 × 10^8)]/451.83× 10^-24

λ=(0.00043965) × (1Kj/1000J) × (10^9nm/1m)

λ=439.7nm

Hence, the longest wavelength of radiation with enough energy to break carbon-sulfur bonds is 439.7nm

4 0

2 years ago

Not the best in chemistry please help

aliya0001 [1]

The answer is B the highest point

3 0

3 years ago

Read 2 more answers

Which process is an oxidation?

Zarrin [17]

<span>The problem has to do with oxidation states of the matter. The oxidation state of oxygen will always be -2 with the exception of peroxides which will have a state of -1. The overall balanced state of chemical compounds will be 0, so the oxidation state of Mn in MnO2 will be +4. The oxidation state of MnO4- will then be +7 to balance out to the negative one charge. The state change from +4 to +7 is 3, thus three electrons have to be lost in order for this to happen; a loss of a charge of -3 results in an increase of charge of 3. Oxidation is always the process of 'losing' electrons.

</span><span>E] MnO2(s) MnO4-(aq</span>

4 0

3 years ago

How much energy must be supplied to break a single 21Ne nucleus into separated protons and neutrons if the nucleus has a mass of

love history [14]

Answer:

1)There is 2.68 * 10^-11 J of energy needed

2) The nuclear binding energy for 1 mol of Ne is 1.6 *10^13 J/mol

Explanation:

Step 1: Data given

The nucleus of a21Ne atom has a amass of 20.98846 amu.

Step 2: Calculate number of protons and neutrons

The number of electrons and protons in an 21Ne atom = 10

The number of neutrons = 21 -10 =11

Step 3: mass of the atom

Mass of a proton = 1.00727647 u

Mass of a neutron = 1.0086649 u

The mass of the atom = mass of all neutrons + mass of protons

Mass of atom = 11*1.0086649 + 10*1.00727647 = 21.1680786 amu

Step 4: Calculate change of mass

The change in mass = Mass of atom - mass of neon

Δmass = 21.1680786 - 20.98846

Δmass = 0.1796186

Step 5: Calculate mass for a single nucleus

The change of mass for a single nucleus is = Δmass / number of avogadro

Δmass of nucleus = 0.1796186 / 6.022*10^23

Δmass of nucleus =2.98 * 10^-25 grams = 2.98 * 10^-28 kg

Step 6: Calculate energy to break a Ne nucleus

Calculate the amount of energy to break a Ne nucleus

ΔEnucleus = Δmass of nucleus * c²

⇒ with c = 2.9979 *10^8 m/s

ΔEnucleus = 2.98 * 10^-28 kg * (2.9979*10^8)² = 2.68 * 10^-11 J

What is the nuclear binding energy for 1 mol of Ne?

ΔE= ΔEnucleus * number of avogadro

ΔE= 2.68 * 10^-11 J * 6.022*10^23

ΔE= 1.6 *10^13 J/mol

3 0

3 years ago