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2 years ago

Item 3

Chemistry

1 answer:

svetoff [14.1K]2 years ago

6 0

Answer:

Semiconductors are poor conductors at low temperatures, but their resistance decreases with increasing temperature.

Explanation:

A semiconductor can be defined as a crystalline solid substance that has its conductivity lying between that of a metal and an insulator, due to the effects of temperature or an addition of an impurity. Semiconductors are classified into two main categories;

1. Extrinsic semiconductor.

2. Intrinsic semiconductor.

The statement which best describes the electrical conductivity of metals and semiconductors is that semiconductors are poor conductors at low temperatures, but their resistance decreases with increasing temperature.

This ultimately implies that, semiconductors are typically an insulator (poor conductor) at low temperatures and a good conductor at high temperatures.

Additionally, conduction involves the transfer of electric charge or thermal energy due to the movement of particles. When the conduction relates to electric charge, it is known as electrical conduction while when it relates to thermal energy, it is known as heat conduction.

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for the reaction HCI+NaOH➡️NaCi+H2O, how many moles of hydrochloric acid are required to produce 150 g. of water?

Ne4ueva [31]

Answer: 8.33 mol of HCl (Hydrochloric Acid)

Explanation:

150 g H2O x __1 mol__ x __1 mol HCl__ = 8.33 mol of HCl

18.016 g 1 mol H2O

6 0

2 years ago

The standard cell potential Ec for the reduction of silver ions with elemental copper is 0.46V at 25 degrees celsius. calculate

Cloud [144]

Answer : The $\Delta G$ for this reaction is, -88780 J/mole.

Solution :

The balanced cell reaction will be,

$Cu(s)+2Ag^+(aq)\rightarrow Cu^{2+}(aq)+2Ag(s)$

Here, magnesium (Cu) undergoes oxidation by loss of electrons, thus act as anode. silver (Ag) undergoes reduction by gain of electrons and thus act as cathode.

The half oxidation-reduction reaction will be :

Oxidation : $Cu\rightarrow Cu^{2+}+2e^-$

Reduction : $2Ag^++2e^-\rightarrow 2Ag$

Now we have to calculate the Gibbs free energy.

Formula used :

$\Delta G^o=-nFE^o$

where,

$\Delta G^o$ = Gibbs free energy = ?

n = number of electrons to balance the reaction = 2

F = Faraday constant = 96500 C/mole

$E^o$ = standard e.m.f of cell = 0.46 V

Now put all the given values in this formula, we get the Gibbs free energy.

$\Delta G^o=-(2\times 96500\times 0.46)=-88780J/mole$

Therefore, the $\Delta G$ for this reaction is, -88780 J/mole.

7 0

3 years ago

When chemists convert ethene (C2H2) to ethanol (CH3CH2OH), they have a mixture of the two gaseous substances. Why do chemists th

emmainna [20.7K]

Answer:

to collect liquid ethanol and leave ethene as a gas because ethanol has hydrogen bonds

Explanation:

The chemist would be lesser than the temperature of the mixture as to collect the liquid ethanol and then leave ethene as a gas since the ethanol is a bond that should be hydrogen. Also -OH that available in the ethanol would be responsible for the hydrogen bonds also it is the main and significant molecular forice

So as per the given situation the above represent the answer

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3 years ago

Unit processes in charge of smelting

Svet_ta [14]

Answer:

Smelting, process by which a metal is obtained, either as the element or as a simple compound, from its ore by heating beyond the melting point, ordinarily in the presence of oxidizing agents, such as air, or reducing agents, such as coke.

Hope I helped!

Explanation:

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3 years ago

Consider the formula for glucose: C6H12O6. What does this indicate about the relationship of the reactants to glucose?

stellarik [79]

The correct option is D.

The reactants that combine together to form glucose are carbon dioxide, water and energy from the sun. Six molecules of carbon dioxide combine with six molecules of water in the presence of sunlight to form glucose. The chemical equation for the reaction is given below"

6CO2 + 6H2O + Sunlight = C6H12O6.

6 0

3 years ago

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