Which of the following amino acids have more than one asymmetric center?

Explain why the product at the negative electrode is not always a metal.

Elena-2011 [213]

Answer:

Whether you get the metal or hydrogen during electrolysis depends on the position of the metal in the reactivity series: the metal will be produced if it is less reactive than hydrogen. hydrogen will be produced if the metal is more reactive than hydrogen.

3 0

3 years ago

Which one of the following represents a decrease in entropy?

Leni [432]

Answer:

D

Explanation:

There are principally three states of matter. These are the solid, liquid and gaseous states. The gaseous state has the highest degree of disorderliness as gas particles can move randomly while the solid state has the highest level of compactness.

Hence, we need to be adequately fed with information as regards the phase change to know if entropy has decreased or increased.

A. is wrong

Evaporation is a change of state to the gaseous state meaning there is an increased entropy.

B. is wrong

Sublimation is a change of state which means a solid substance like iodine or naphthalene changes its state directly to the gaseous state. There is an increased entropy here too.

C is wrong

Melting of ice means going from ice block to liquid water. This is synonymous to going from the solid state to the liquid state which is an increased entropy

D is correct

Condensation involves going from the gaseous state to the liquid state. This means going from a less ordered state to a more ordered state. This is accompanied by an entropy decrease.

E is wrong

While there are some processes that increase entropy, we also have some process that decrease entropy.

7 0

3 years ago

PLEASE HELP ASAP

erma4kov [3.2K]

In the so called rain shadow effect we have interaction between all of the four major Earth spheres. When we have a coastal region where there's a high mountain range, the part of the mountain that is facing the sea will differ a lot from the part of the mountain that is on the other side. The water from the sea evaporates. The water vapor makes the air wet. The warm and wet air masses from the sea will come to the coastline, once they reach the mountain they will start to accumulate as they can not pass through it. As they accumulate rainfall appears. The rainfall contributes to a lush vegetation on this side of the mountain (windward side). The rain shadow effect appears on the leeward side of the mountain, and it mostly gets dry, strong, downward winds. These conditions result in drier climate, much less vegetation, and much increased erosion. Thus we can easily see that we have in this case interaction between the hydrosphere (the sea and the rainfall), the geosphere (the ground, soil, rocks), biosphere (the vegetation), and atmosphere (the winds, the clouds).

6 0

3 years ago

A bomb calorimetric experiment was run to determine the enthalpy of combustion of ethanol. The reaction is The bomb had a heat c

gulaghasi [49]

Answer:

The enthalpy of combustion of ethanol in kJ/mol is -1419.58 kJ/mol.

Explanation:

The heat absorbed by the bomb and water is equal to the product of the heat capacity and the temperature change. Working with this equation, and assuming no heat is lost to the surroundings, we write :

qcal= Ccal × ΔT= 490 J/K × 276.7 K= 135,583 J = 135.58 kJ

Note we expressed the temperature change in K, because the heat capacity is written in K.

Now that we have the heat of combustion, we need to calculate the molar heat.

Because qsystem = qrxn + qcal and qrxn = -qcal, the heat change of the reaction is -135.58 kJ.

This is the heat released by the combustion of 4.40 g of ethanol ; therefore, we can write the conversion factor as 135.58 kJ/ 4.40 g.

The molar mass of ethanol is 46.07 g, so the heat of combustion of 1 mole of ethanol is :

molar heat of combustion= -135.58 kJ/4.40 g x 46.07 g/ 1 mol= -1419.58 kJ/mol

Therefore, the enthalpy of combustion of ethanol in kJ/mol is -1419.58 kJ/mol.

3 0

3 years ago

Which nonmetals have similar chemical properties? Check all that apply.

alisha [4.7K]

Answer:

Sulfur

Selenium

Oxygen

Explanation:

You’re welcome:)

7 0

3 years ago

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