Answer: 4.18925 kJ heat is needed to convert 25.0 g of solid ethanol at -135 °C to liquid ethanol at -50°C.
Explanation:
Temperature of Solid
Melting temperature of Solid
Temperature of liquid
Specific heats of solid ethanol = 0.97 J/gK
Specific heats of liquid ethanol = 2.3 J/gK
Heat required to melt the the 25 g solid at 159 K
= 159 K - 138 K = 21 K
Heat required to melt and raise the temperature of upto 223 K
= 223 K - 159 K = 64 K
Total heat to convert solid ethanol to liquid ethanol at given temperature :
(1kJ=1000J)
Hence, 4.18925 kJ of heat will be required to convert 25.0 g of solid ethanol at -135 °C to liquid ethanol at -50°C.
D. It is the heat required to change a gram of substance from a liquid to a gas.
Explanation:
The heat of vaporization is the heat required to change a gram of substance from a liquid to a gas.
- It is also known as the enthalpy of vaporization.
- The heat of vaporization is the quantity of heat needed to change one gram of a substance from liquid to gas.
- This heat of vaporization is dependent on the pressure conditions the process is taking place.
- Different liquids have their heat of vaporization.
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Heat of vaporization brainly.com/question/9529654
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When a gas changes into a liquid, it is called Condensation, and the speed of the molecules is slower.
Hope this helps you :)))
Answer:
See figure 1
Explanation:
For this question, we can start with the structure of <u>pyruvic acid</u>. In this molecule, we have two functional groups, the <u>ketone group</u>, and a <u>carboxylic acid group</u>.
In the acid group, we have an acidic hydrogen. That is, this hydrogen can leave the molecule to produce a <u>hydronium ion</u> ().
Now, to know what is the pH at which this hydrogen leaves the molecule we must look for the <u>pKa value</u>. Which for the case of this molecule is <u>2.45</u>
If there is a pH value greater than 2.45, the molecule will lose hydrogen. In this case, we will have a value above 2.45 (7.4), which is why the conjugated acid of pyruvic acid will be produced, which is <u>pyruvate</u>.
Therefore, in the structure, we will have a negative charge on the acid group.
See figure 1
I hope it helps!