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3 years ago

SEP Develop Models Each helium atom has two protons. Sketch models

Chemistry

1 answer:

RSB [31]3 years ago

6 0

Protons and neutrons are located in the nucleus of the atom while the electrons move in the trajectory of the shell

<h3>Further explanation </h3>

Isotopes are atoms whose no-atom has the same number of protons while still having a different number of neutrons.

So Isotopes are elements that have the same Atomic Number (Proton)

Isotopes of Helium : helium-3 and helium-4

₂³He :

protons = 2

electrons=protons=2

neutron=mass number-atomic number=3-2=1

₂³He :

protons = 2

electrons=protons=2

neutron=mass number-atomic number=3-2=1

₂⁴He

protons = 2

electrons=protons=2

neutron=mass number-atomic number=4-2=2

Protons and neutron in the nucleus, electrons in the shell

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Ultraviolet radiation has a frequency of 6.8×1015 Hz. What is the energy associated with this frequency?

stellarik [79]

Use Planck's equation (E=hv) to solve. where frequency (v) of ultrviolet radiation is 6.8 × 1015 1/s. The variable h is a constant equal to 6.63 × 10-34 J·s
E= (6.8 × 1015 1/s)x(6.63 × 10-34 J·s)

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3 years ago

Are the bases on the interior or the exterior of the double helix? Are they randomly arranged or neatly stacked?

Lemur [1.5K]

the double helix is hydrogen bonded through the bases only so the bases are inside the helix only

as adenine combines with thymine and guanine with cytosine

phosphate are in the exterior of it

sugar groups constitute the double helix.

3 0

3 years ago

Read 2 more answers

Neutral atoms of argon, atomic number 18, have the same number of electrons as each of the following items except: Cl- S -2 K+ C

irinina [24]

Answer:

Ne.

Explanation:

Neutral argon, atomic number 18, has 18 electrons.

Cl⁻:

Neutral atom of Cl, atomic number 17, has 17 electrons.

When it gains electron and be Cl⁻, then it has 18 electrons a neutral Ar.

S²⁻:

Neutral atom of S, atomic number 16, has 16 electrons.

When it gains 2 electrons and be S²⁻, then it has 18 electrons a neutral Ar.

K⁺:

Neutral atom of K, atomic number 19, has 19 electrons.

When it losses electron and be K⁺, then it has 18 electrons a neutral Ar.

Ca²⁺:

Neutral atom of Ca, atomic number 20, has 20 electrons.

When it losses 2 electrons and be Ca²⁺, then it has 18 electrons a neutral Ar.

Ne:

It is a noble gas that has 10 electrons.

So, the right choice is: Ne.

3 0

2 years ago

In the reaction A + B C, doubling the concentration of A doubles the reaction rate and doubling the concentration of B does not

frutty [35]

Answer:

rate = k[A]

Explanation:

The equation that relate reaction rate with reactant concentrations is known as the rate law.

for a reaction:

A + B → C

the rate law can be expressed as:

Rate = k[A]ᵃ[B]ᵇ

The proportionality constant, k, is known as the rate constant, the powers a and b is the reaction order with respect to reactants A and B, respectively.

for this reaction doubling the concentration of A doubles the reaction rate that means

Rate₂ = 2 *Rate₁ and [A]₂ = 2 [A]₁

Rate₁ = k[A]₁ᵃ[B]ᵇ → eq. 1

Rate₂ = k[A]₂ᵃ[B]ᵇ → eq. 2

Dividing eq. 2 by eq. 1 one can get

(Rate₂ / Rate₁) = (k [A]₂ᵃ[B]ᵇ) / (k[A]₁ᵃ[B]ᵇ)

using

Rate₂ = 2 *Rate₁ and [A]₂ = 2 [A]₁

∴ (2 Rate₁ / Rate₁) = ( k [2]ᵃ[B]ᵇ) / (k[1]ᵃ[B]ᵇ)

(2) = (2)ᵃ
taking log of both sides
log (2) = a Log (2)
0.693 = a * 0.693
a =1

∴ order of reaction with respect to A is first (=1) → (1)

Doubling the concentration of B does not affect the reaction rate.

that means

Rate₂ = Rate₁ and [B]₂ = 2 [B]₁

Rate₁ = k[A]ᵃ[B]₁ᵇ → eq. 1

Rate₂ = k[A]ᵃ[B]₂ᵇ → eq. 2

Dividing eq. 2 by eq. 1 one can get

(Rate₂ / Rate₁) = (k [A]ᵃ[B]₂ᵇ) / (k[A]ᵃ[B]₁ᵇ)

using

Rate₂ = Rate₁ and [B]₂ = 2 [B]₁

∴ (Rate₁ / Rate₁) = ( k [A]ᵃ[2]ᵇ) / (k[A]ᵃ[1]ᵇ)

(1) = (2)ᵇ
taking log of both sides
log (1) = b Log (2)
0 = 0.693 * b
b = 0

∴ order of reaction with respect to B is zero → (2)

So, from 1 and 2 the right choice is rate = k[A]¹[B]⁰= k[A]

6 0

3 years ago

Two identical dump trucks are at a work site. One is returning with a full load, and the other is empty. Both are traveling at 3

elena55 [62]

Answer:

The one with the full load.

Explanation: We can prove this by doing V^2 X M = KE

where V= velocity M= mass and KE= kinetic energy.

is both are traveling at the same speed (let's say 2kmph) and one has a mass of 50 kg with the other having a mass of 100kg.

(plug in the values) . 2^2 X 50 = KE and 2^2 X 100= KE

(simplify) 200=KE and 400=KE

This proves that a dump truck with a larger load (if traveling at the same speed) will always contain more energy than a dump truck with a smaller load.

8 0

2 years ago