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4 years ago

Define what is vsepr theory?

Physics

1 answer:

maks197457 [2]4 years ago

6 0

Answer:

Valence shell electron pair repulsion theory

Explanation:

VSEPR stands for valence shell electron pair repulsion theory in which helps in predicting the geometric shape of a molecule based upon the number of lone pairs of electrons.

It is also called the Gillespie-Nyholm theory after its two main discoverers, Ronald Gillespie and Ronald Nyholm.

In this theory the lone pair of atoms of the valence shell repel each other and attain such an angular position which minimizes the repulsion between the lone pair of electrons and the bonded pair of electrons so that it attains a stable state.

This theory is however not related to the wave function and the orbital hybridization but is based only upon the electron density.

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Artyom0805 [142]

The vibrations of the fields are at 90° angles to the direction of the motion of the wave

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3 years ago

A proton travels with a speed of 4.2×106 m/s at an angle of 30◦ west of north. A magnetic field of 2.5 T points to the north. Fi

Arada [10]

Answer:

$8.4\cdot 10^{-13} N$

Explanation:

The magnitude of the magnetic force on the proton is given by:

$F=qvB sin \theta$

where:

$q=1.6\cdot 10^{-19} C$ is the proton charge

$v=4.2\cdot 10^6 m/s$ is the proton velocity

$B=2.5 T$ is the magnetic field

$\theta=30^{\circ}$ is the angle between the direction of v and B

Substituting into the formula, we find

$F=(1.6\cdot 10^{-19}C)(4.2\cdot 10^6 m/s)(2.5 T) sin 30^{\circ}=8.4\cdot 10^{-13} N$

6 0

3 years ago

A 238 92U nucleus is moving in the x-direction at 5.0 × 105 m/s when it decays into an alpha particle 4 2He and a 234 90Th. If t

nexus9112 [7]

Answer:

v_th = 3.1 * 10^5 m/s

Explanation:

Given:

- mass of 238-Uranium m_u = 3.952 *10^-25 kg

- mass of alpha particle m_a = 6.64 * 10^-27 kg

- mass of thorium particle m_th = 3.885*10^-25 kg

- velocity of 238-Uranium v_u = 5.0 *10^5 m/s

- velocity of alpha particle v_a = 1.4 *10^7 m/s

Find:

- The recoil velocity of the thorium particle.

Solution:

- To solve this problem we will use conservation of momentum in both x and y direction.

- Momentum conservation in x-direction:

P_i = P_f

m_u*v_u = m_a*v_a*cos(Q) + m_th*v_th,x

where v_th,x is the x component of thorium velocity:

P_i = 3.952 *10^-25 * 5.0 *10^5 = 1.976*10^-19

P_f = 6.64 * 10^-27*1.4 *10^7*cos(25.4) + 3.885*10^-25*v_th,x

P_f = 8.3974*10^-20 + 3.885*10^-25*v_th,x

Hence,

1.976*10^-19 = 9.296*10^-20 + 3.885*10^-25*v_th,x

v_th,x = 2.92473 * 10^5 m/s

- Momentum conservation in y-direction:

P_i = P_f

0 = m_a*v_a*sin(Q) + m_th*v_th,y

where v_th,x is the x component of thorium velocity:

v_th,y = m_a*v_a*sin(Q) / m_th

v_th,y = 6.64 * 10^-27*1.4 *10^7*sin(25.4) / 3.885*10^-25

Hence,

v_th,y = 1.02635 * 10^5 m/s

- The magnitude of recoil velocity:

v_th = sqrt ( v_th,x ^2 + v_th,y ^2 )

v_th = sqrt ( (2.92473 * 10^5)^2 + (1.02635 * 10^5)^2 )

v_th = 3.1 * 10^5 m/s

4 0

4 years ago

A block of lead has dimensions of 4.50cm by 5.20cm by 6.00cm. The block weighs 1587g. From this information, calculate the densi

postnew [5]

Density = Mass / Volume
Volume = Area x Length = (4.50 x 5.20) x 6.00 = 140.4
Density = 1587 x 140.4 = 222,814.8 g/cm3 (cubed)
222,814.8 / 1000 = 222.8148 kg/m3 (cubed)

4 0

3 years ago

Describe how kinetic and potential energy change as a diver climbs up to a diving board and then dives into the water below.

Dima020 [189]

A diver having mass m climbs up the diving board.
We know that Gravitational potential energy is given as PEG=mgΔh

What changes is his Gravitational potential energy due to change of height Δh with reference to the ground/water level.
While standing on the diving board his velocity is zero. As such kinetic energy is also zero.

Once he jumps off the springboard we see he gets additional energy from the springboard and falls down under action of gravity g. Due to decrease of height above the ground level Gravitational potential energy decreases and gets converted in to his kinetic energy. 1/2mv2.

While in air he encounters air resistance. Some of his energy is spent in overcoming this resistance. Gets converted in to kinetic and thermal energy of surrounding air and his body.

Once diver reaches the water, we see water splashing and hear noise of splash. Thereafter the diver comes to rest. Now his potential energy becomes zero. And converted kinetic energy has been converted in to kinetic energy, heat energy and sound energy of water.

As such energy transformation equation looks like

Gravitational PE+Elastic PE of springboard→Kinetic energy of air and water+Sound energy of splash+thermal energy

8 0

3 years ago

Read 2 more answers