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blagie [28]
3 years ago
10

În ce raport de mase trebuie amestecate două cantități din același lichid, având temperaturile t1=10 grade Celsius, respectiv t2

=65 grade Celsius, pentru a obține o temperatură de echilibru t=45 grade Celsius?
Physics
1 answer:
Brilliant_brown [7]3 years ago
8 0

Răspuns:

7: 4

Explicaţie:

Formula pentru calcularea cantității de căldură absorbită este exprimată ca;

Q = mc∆t

m este masa substanței

c este capacitatea termică specifică

∆t este schimbarea temperaturii

Conform legii calorimetriei, căldura pierdută de substanța rece = căldura câștigată de substanța fierbinte.

Folosind formula

(mc∆t) rece = (mc∆t) fierbinte

McCw∆tc = MhCw∆th

Deoarece au aceeași capacitate de căldură specifică, se vor anula. Ecuația devine;

Mc∆tc = Mh∆th ...... 1

Pentru apa rece;

∆tc = 45 ° C - 10 ° C

∆tc = 35 ° C

Pentru apa fierbinte:

∆th = 65 ° C - 45 ° C

∆th = 20 ° C

Înlocuiți în ecuația 1;

Mc (35) = Mh (20)

35Mc = 20Mh

Luând raportul dintre masa apei reci și cea fierbinte:

Mh / Mc = 35/20

Mh / Mc = 7/4

Prin urmare, lichidul trebuie amestecat împreună în raportul 7: 4

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b)

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c)

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f)

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When a glass rod is rubbed with silk, charging by friction occurs, similar to part a). However in this case, the glass rod gives off electrons to the silk: therefore, the glass rod remains positively charged.

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h)

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3 years ago
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