Consider the heating curve for water. A graph of the heating curve for water has time in minutes on the horizontal axis and Temp
erature in degrees Celsius on the vertical axis. A line runs through the following points: 0 minutes, negative 20 degrees; 0.5 minutes, 0 degrees; 2 minutes, 0 degrees; 4 minutes, 100 degrees; 8 minutes, 100 degrees; 9.5 minutes, 160 degrees. At what temperature does the solid start melting? –20°C 0°C 20°C 80°C
1 answer:
Answer:
0°C.
Explanation:
Hello,
In this case, given the heating curve of water on the attached document, we can notice that at 0 °C the solid starts melting, which means that the melting point is reached. Melting point is known as a physical change whereby a solid changes to liquid by the addition of heat as it allows the molecules to separate to each other.
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If the coulombs are supplied at 1.44 V, then 4.766 × 10¹¹ joules are produced.
(a) The reaction is
2H₂O + 2e⁻ → H₂ + 2OH⁻
According to the reaction, 2 moles of electrons flow per mole of reaction,
(b) Given
T = 25°C
Change Celsius into Kelvin
T = 25°C
= (25 + 273 ) K
= 298 K
<h3>What is Ideal Gas Law ?</h3>It is expressed as
PV = nRT
Hence ,
n =
=
= 1.7176 ×10⁶ mole
Now, From the given reaction we can say that ,1 mole of H₂ is produced by 2 moles of electron
Hence, 1.7176 × 10⁶ mole of H₂ is produced by
= 2 × 1.7176 × 10⁶ moles of electron
= 3.435 ×10⁶ moles of electron
We know that
charge = moles of electron × F
= (3.435 ×10⁶ × 96500) C
= 3.31 × 10¹¹ C
(c) We know that,
Voltage = =
1.44 V =
Energy = 1.44 V × 3.31 × 10¹¹ C
= 4.766 × 10¹¹ Joules
Thus from the above conclusion we can say that, coulombs are supplied at 1.44 V, then 4.766 × 10¹¹ joules are produced.
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Question : Car manufacturers are developing engines that use H₂ as fuel. In Iceland, Sweden, and other parts of Scandinavia countries, where hydroelectric plants produce inexpensive electric power, the H₂ can be made industrially by the electrolysis of water.
a) How many moles of electrons flow per mole of reaction ?
b) How many coulombs are needed to produce 3.53X10⁶ L of H₂ gas at 12.0 atm and 25°C.
c) If the coulombs are supplied at 1.44 V, how many joules are produced?