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3 years ago

Elements whose properties are between those of metals and solid nonmetals are called:

Chemistry

2 answers:

Charra [1.4K]3 years ago

6 0

Answer:

metalloids

Explanation:

they are solid at roomtempreture and alloys with metals.

examples boron,silicon,arsenic,tellurium

Tom [10]3 years ago

4 0

Answer:

mettaliods

Explanation:

It has the both property of metal and non metal so it is called mettaliod.

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Which one of the following systems has the highest entropy?

Veronika [31]

Answer: a

Explanation:

8 0

3 years ago

An ideal gas contained in a piston-cylinder assembly is compressed isothermally in an internally reversible process.

Tju [1.3M]

Answer:

a) $\Delta S$

b) entropy of the sistem equal to a), entropy of the universe grater than a).

Explanation:

a) The change of entropy for a reversible process:

$\delta S=\frac{\delta Q}{T}$

$\Delta S=\frac{Q}{T}$

The energy balance:

$\delta U=[tex]\delta Q- \delta W$

If the process is isothermical the U doesn't change:

$0=[tex]\delta Q- \delta W$

$\delta Q= \delta W$

$Q= W$

The work:

$W=\int_{V1}^{V2}P*dV$

If it is an ideal gas:

$P=\frac{n*R*T}{V}$

$W=\int_{V1}^{V2}\frac{n*R*T}{V}*dV$

Solving:

$W=n*R*T*ln(V2/V1)$

Replacing:

$\Delta S=\frac{n*R*T*ln(V2/V1)}{T}$

$\Delta S=n*R*ln(V2/V1)}$

Given that it's a compression: V2<V1 and ln(V2/V1)<0. So:

$\Delta S$

b) The entropy change of the sistem will be equal to the calculated in a), but the change of entropy of the universe will be 0 in a) (reversible process) and in b) has to be positive given that it is an irreversible process.

7 0

3 years ago

The following reaction plays a key role in the destruction of ozone In the atmosphere:

lys-0071 [83]

Answer:

19.91 J/K

Explanation:

The entropy is a measure of the randomness of the system, and it intends to increase in nature, thus for a spontaneous reaction ΔS > 0.

The entropy variation can be found by:

ΔS = ∑n*S° products - ∑n*S° reactants

Where n is the coefficient of the substance. The value of S° (standard molar entropy) can be found at a thermodynamic table.

S°, Cl(g) = 165.20 J/mol.K

S°, O3(g) = 238.93 J/mol.K

S°, O2(g) = 205.138 J/mol.K

So:

ΔS = (1*205.138 + 1*218.9) - (1*165.20 + 1*238.93)

ΔS = 19.91 J/K

6 0

3 years ago

Which of the following ions is formed when a base is dissolved in a solution?

Aneli [31]

Answer:

$\huge\boxed{\sf OH-}$

Explanation:

<u>According to Arrhenius concept of acid and base:</u>

"When a base in a solution, produces/yields OH- (Hydroxide) ions."

So, when a base is dissolved in a solution, it produces OH- ions.

<u>For example:</u>

NaOH ⇄ Na⁺ + OH⁻ (So, it is a base)

$\rule[225]{225}{2}$

Hope this helped!

3 0

2 years ago

The laws of electrostatics predict that protons will

GaryK [48]

The laws of the electrostatics were developed by Coulomb and are further detailed or subdivided into two as follows:

(1) The first one talks about the similarities in the charges of the particles and what happens to them. This states that like charges repel.

(2) The second one quantifies the field between two particles with equation showing that field is directly proportional to the masses and inversely to the square of the distance between them.

In this item, we can then say that the protons (having the same charges) will have to repel from each other in accordance to statement 1 of the law.

3 0

3 years ago