Teach me

[Kenny Pollock 10+ year member]

I'm stuck on these problems, can you tell me how to get the answer?

An air conditioning unit contains 2.38 kg of water at room temperature. If the specific heat of water is 4.186 J/gºC, how much heat does the water lose to cool down from 30ºC to 4ºC?

259.03 x 103 Joules

259.03 Joules

45.73 x 103 Joules

14.78 x 103 Joules

0.25903 Joules

200.0 Joules of heat is required to raise the temperature of an object sample by 3.00ºC. If the specific heat of the object is .01490 J/gºC, what is the mass of the sample in kilograms?

0.993 x 10-3 kg

4474.3 kg

4.474 kg

40.268 kg

0.067 kg

The specific heat of a special ceramic tile is 140,000 J/g°C. If 20.0 grams of this ceramic material had a temperature gain of 20°C, how much heat was absorbed by this material?

28,000 cal

56,000,000 Joules

48,000,00 Joules

None are correct.

A 2.00-kg metal object requires 5020 J of heat to raise its temperature from 20.0°C to 40.0°C. What is the specific heat capacity of the metal?

126 J/(kg • °C)

106 KJ/(kg • °C)

126 cal/(kg • °C)

142 kcal(kg • °C)

1146 joules of heat is released when a 100.0 gram sample of an unknown metal cools from 95.00°C to 65.00°C. Determine the specific heat of a metal.

0.755 J/g°C

1.22 J/g°C

.887 J/g°C

.3820 J/g°C

Click to read more...

 

[Kenny Pollock 10+ year member]

Anyone?

 

[crunktimes.com 5,000+ posts]

...............

 

[thecaraudioguy]

google.com

Find the formula for specific heat. It should be pretty strait forward.

 

[thecaraudioguy]

google.com

Find the formula for specific heat. It should be pretty strait forward.

 

[Kenny Pollock 10+ year member]

Thank you, I got a 14/20 thanks to the formula.

Stupidly I put 4000kg in one question, when it's really 4kg

 

[Kenny Pollock 10+ year member]

Now I have to figure out how to do this:

Electromagnetic radiation at the blue end of the visible spectrum has a wavelength of 400 nm. Calculate the frequency of the radiation.

 

[mikey060 10+ year member]

Q = mc delta t?

lol for the origional questions

 

[Kenny Pollock 10+ year member]

Reading over the notes... they have C (velocity) = ^V (wave length x frequency)

So 2.99792x10^8 = (400)(x) solve for x? Or what?

 

[mikey060 10+ year member]

Now I have to figure out how to do this:Electromagnetic radiation at the blue end of the visible spectrum has a wavelength of 400 nm. Calculate the frequency of the radiation.

conver nm to m..then divide the speed of light by it

 

[Kenny Pollock 10+ year member]

4 nm = .0000004 meters?

So

299,792,458 / .0000004 = 7.49481145 × 10^14?

 

[Kenny Pollock 10+ year member]

What is the fuel for the nuclear reaction in the sun?

What type of nuclear reaction takes place in a nuclear reactor?

This is simple I think, but I think I'm wrong..

Fuel for nuclear reaction... I don't know what fuels fusion, unless fusion is the answer

And I'm pretty sure fission occurs in the nuclear reactor

 

[mikey060 10+ year member]

the reaction in the sun is the fusion of hydrogen. same with atomic bombs, they are also called hydrogen bombs

i dotn remeber what nuclear reactions are. i think they are fusion

 

[Kenny Pollock 10+ year member]

A pot of water (2.5 Liters of water) initially at 25.0 degrees C is heated to boiling. How much energy is needed to heat the water? The density of water is 1 g/ml.

So 2.5L = 2500mL, which is 2500g in this equation, correct?

Boiling is 100 degrees C, so difference between them is 75 degrees, right?

So 75 = (x)(2500)(75)? Or no?