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2 years ago

The radioactive isotope U-238 has protons and neutrons.

Physics

2 answers:

Sergio039 [100]2 years ago

8 0

Answer:

92; 146

Explanation:

Uranium has 92 protons, and 238 is the mass number of the element. The mass number is the sum of the number of neutrons and protons in an element.

Thus, 238 = 92 + neutrons

neutrons = 238 - 92

= 146

Hope this helps!

Archy [21]2 years ago

4 0

Answer:

92 protons, 146 neutrons

Explanation:

Uranium will always have the same amount of protons, because that is what defines the element. Uranium has 92 protons, meaning that the rest of the mass of the atom comes from neutrons. 238-92=146 neutrons. Hope this helps!

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If an object has zero acceleration, does it have to have zero velocity?

adelina 88 [10]

Answer:

Yes, the velocity would also be zero.

Explanation:

Acceleration is the change in velocity over time, therefore, there has to be a change in velocity for something to accelerate. which means without acceleration, the object has no velocity.

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2 years ago

Which term refers to the energy that is stored or released during a change of state of water

Dima020 [189]

The appropriate term is latent heat. This energy is released as the water changes state from a gas to liquid....a liquid to solid etc. the latent heat is either absorbed or given off by the water as it changes its physical state. Latent heat of fusion is associated with freezing a liquid or melting a solid.

8 0

2 years ago

Read 2 more answers

An open container holds ice of mass 0.555 kg at a temperature of -16.6 ∘C . The mass of the container can be ignored. Heat is su

s2008m [1.1K]

Answer: A. 23.59 minutes.

B. 249.65 minutes

Explanation: This question involves the concept of Latent Heat and specific heat capacities of water in solid phase.

Latent heat of fusion is the total amount of heat rejected from the unit mass of water at 0 degree Celsius to convert completely into ice of 0 degree Celsius (and the heat required for vice-versa process).

Specific heat capacity of a substance is the amount of heat required by the unit mass of a substance to raise its temperature by 1 kelvin.

Here, given that:

mass of ice, m= 0.555 kg

temperature of ice, T= -16.6°C

rate of heat transfer, $q=820 J.min^{-1}$

specific heat of ice, $c_{i}= 2100 J.kg^{-1}.K^{-1}$

latent heat of fusion of ice, $L_{i}=334\times10^{3}J.kg^{-1}$

Asked:

1. Time require for the ice to start melting.

2. Time required to raise the temperature above freezing point.

Sol.: 1.

We have the formula:

$Q=mc\Delta T$

Using above equation we find the total heat required to bring the ice from -16.6°C to 0°C.

$Q= 0.555\times2100\times16.6$

$Q= 19347.3 J$

Now, we require 19347.3 joules of heat to bring the ice to 0°C and then on further addition of heat it starts melting.

∴The time required before the ice starts to melt is the time required to bring the ice to 0°C.

$t=\frac{Q}{q}$

$=\frac{19347.3}{820}$

= 23.59 minutes.

Sol.: 2.

Next we need to find the time it takes before the temperature rises above freezing from the time when heating begins.

Now comes the concept of Latent heat into the play, the temperature does not starts rising for the ice as soon as it reaches at 0°C it takes significant amount of time to raise the temperature because the heat energy is being used to convert the phase of the water molecules from solid to liquid.

From the above solution we have concluded that 23.59 minutes is required for the given ice to come to 0°C, now we need some extra amount of energy to convert this ice to liquid water of 0°C.

We have the equation: latent heat, $Q_{L}= mL_{i}$