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3 years ago

Whitch family has full valence energy level

1 answer:

7 0

Group 0 - they are called the NOBLE GASES
(as they're very unreactive) because...

ALL of their atoms are full.
Example : Helium contains 2 electrons so it's outer shell is full

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Describe and explain how the movement and arrangement of the particles in a block of ice change as the ice melts to form liquid

-BARSIC- [3]

Answer:

Ice is water in solid phase, in this phase, the particles are very close together and relatively in fixed positions.

As the temperature starts to increase (thermal energy), also does the kinetic energy of the particles (so we have a change from thermal energy to kinetic energy), so they start to move "more", and the position of the particles starts to be less "fixed". There is a point where the particles have enough energy, and this point is where the phase of the water changes from solid to liquid phase (the fusion point). After this point the water can not hold his shape, and takes the shape of the container where it is.

4 0

3 years ago

A single-phase electrical load draws 600KVA at 0.6 power factor lagging. a) Find the real and reactive power absorbed by the loa

Whitepunk [10]

Answer:

(a). The reactive power is 799.99 KVAR.

(c). The reactive power of a capacitor to be connected across the load to raise the power factor to 0.95 is 790.05 KVAR.

Explanation:

Given that,

Power factor = 0.6

Power = 600 kVA

(a). We need to calculate the reactive power

Using formula of reactive power

$Q=P\tan\phi$ ...(I)

We need to calculate the $\phi$

Using formula of $\phi$

$\phi=\cos^{-1}(Power\ factor)$

Put the value into the formula

$\phi=\cos^{-1}(0.6)$

$\phi=53.13^{\circ}$

Put the value of Φ in equation (I)

$Q=600\tan(53.13)$

$Q=799.99\ kVAR$

(b). We draw the power triangle

(c). We need to calculate the reactive power of a capacitor to be connected across the load to raise the power factor to 0.95

Using formula of reactive power

$Q'=600\tan(0.95)$

$Q'=9.94\ KVAR$

We need to calculate the difference between Q and Q'

$Q''=Q-Q'$

Put the value into the formula

$Q''=799.99-9.94$

$Q''=790.05\ KVAR$

Hence, (a). The reactive power is 799.99 KVAR.

(c). The reactive power of a capacitor to be connected across the load to raise the power factor to 0.95 is 790.05 KVAR.

8 0

3 years ago

In which scenario does radiation occur? warming soup on a stove drying towels at the beach cooking eggs in boiling water warming

shepuryov [24]

Answer: drying towels at the beach.

Explanation:

Radiation simply has to do with the energy that is gotten from a particular source and then goes through some materials. It simply means the way energy is being transmitted as waves or heat through a certain medium.

From the options given, the scenario whereby a radiation takes place is when drying towels on the beach.

8 0

2 years ago

Read 2 more answers

A 200g(m2) mass is pulling the cart (m1) across the table as shown below. If it covers 1.12m in 4.8 seconds starting from rest,

Vsevolod [243]

Answer: 20.21 kg

Explanation:

The mass hanging from the pulley is pulling the cart. The force by which cart is being pulled is equal to weight of the hanging mass.

$F=m_2g$

⇒F=0.200 kg ×9.8 m/s²=1.96 N

Since there is no other force acting on the cart and there is no friction, so this force will pull the cart.

The Cart covers 1.12 m distance in 4.8 s.

From the equation of motion,

s = u t + 0.5 × a t²

We will find the acceleration of the cart,

Distance covered, s = 1.12 m

Initial velocity, u = 0 ( staring from rest)

Time taken, t = 4.8 s

⇒1.12 m = 0 + 0.5 × a × (4.8 s)²

⇒a = 0.097 m/s²

Now the force which causes this acceleration is:

F = ma

where m is the mass of the cart and a is the acceleration of the cart

⇒1.96 N = m×0.097 m/s²

⇒m = 20.21 kg

Hence, the mass of the cart is 20.21 kg.

4 0

3 years ago

What is the change in internal energy of the system (∆U) in a process in which 10 kJ of heat energy is absorbed by the system an

Trava [24]

Answer:

Explanation:

According to first law of thermodynamics:

∆U= q + w

= 10kj+(-70kJ)

-60kJ

, w = + 70 kJ

(work done on the system is positive)

q = -10kJ ( heat is given out, so negative)

∆U = -10 + (+70) = +60 kJ

Thus, the internal energy of the system decreases by 60 kJ.

8 0

3 years ago