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Sphinxa [80]
3 years ago
9

What is an exothermic chemical reaction? A. It is a reaction that converts matter to heat. B. It is a reaction that requires hea

t to proceed. C. It is a reaction that draws heat from its surroundings. D. It is a reaction that releases heat to its surroundings.
Physics
2 answers:
alukav5142 [94]3 years ago
4 0

Answer: The answer is

D. It is a reaction that releases heat to its surroundings.

Explanation:

An exothermic reaction is a reaction in which the overall standard enthalpy change to negative. And  Exothermic reactions usually release heat and entail the replacement of weak bonds with stronger ones.

nordsb [41]3 years ago
3 0

it is D exo means realease

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The centripetal force exerted on stunt motorcyclist Biker Bob while riding on the inner vertical surface of a circular track is:
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Answer:

option C

Explanation:

The correct answer is option C.

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7 0
3 years ago
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.

<em>Latent heat </em><em>of fusion </em>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).

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

Here, <u>given that</u>:

  • 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}

<u>Asked:</u>

1. Time require for the ice to start melting.

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

Sol.: 1.

<u>We have the formula:</u>

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.

<em>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.</em>

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.

<u>We have the equation:</u> latent heat, Q_{L}= mL_{i}

Q_{L}= 0.555\times334\times10^{3}= 185370 J

<u>Now  the time required for supply of 185370 J:</u>

t=\frac{Q_{L}}{q}

t=\frac{185370}{820}

t= 226.06 minutes

∴ The time it takes before the temperature rises above freezing from the time when heating begins= 226.06 + 23.59

= 249.65 minutes

8 0
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Ronch [10]

Correct answer choice is :



B) Able to travel through a vacuum.



Explanation:



Electromagnetic waves are applied to carry long/short/FM wavelength radio waves, and TV/telephone/wireless signals or services. They are also effective for transferring energy in the form of microwaves, infrared radiation, visible light, ultraviolet light, X-rays, and gamma rays. Electromagnetic waves change from mechanical waves in that they do not need a medium to generate. This means that electromagnetic waves can move not only in the air and solid matters but also in the void of space.


Read more on Brainly.com - brainly.com/question/1697984#readmore

4 0
3 years ago
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