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4 years ago

QUESTION 45

Chemistry

1 answer:

notka56 [123]4 years ago

3 0

Answer:

Silicone rubber impression materials exhibiting strength, elasticity and dimensional stability were discovered in 1955 in University of Liverpool by S.L. Pearson.

Explanation:

• Silicone rubber is a high-performance elastomers which characterized by an unusual combination of properties.

• Excellent electrical insulation properties as well as its transparency, these properties range from high temperature performance to durability.

• Rubber like material composed of silicone containing silicone together with other molecule like, hydrogen, carbon and oxygen.

• Its structure always comprises silicone-oxygen chain and an organic moiety bound to the silicon e.

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Answer:

(a) rate = -(1/3) Δ[O₂]/Δt = +(1/2) Δ[O₃]/Δt

(b) Δ[O₃]/Δt = 1.07x10⁻⁵ mol/Ls

Explanation:

By definition, t<u>he reaction rate for a chemical reaction can be expressed by the decrease in the concentration of reactants or the increase in the concentration of products:</u>

aX → bY (1)

$rate= -\frac{1}{a} \frac{\Delta[X]}{ \Delta t} = +\frac{1}{b} \frac{\Delta[Y]}{ \Delta t}$

<em>where, a and b are the coefficients of de reactant X and product Y, respectively. </em>

(a) Based on the definition above, we can express the rate of reaction (2) as follows:

3O₂(g) → 2O₃(g) (2)

$rate = -\frac{1}{3} \frac{\Delta[O_{2}]}{\Delta t} = +\frac{1}{2} \frac{ \Delta[O_{3}]}{ \Delta t}$ (3)

(b) From the rate of disappearance of O₂ in equation (3), we can find the rate of appearance of O₃:

$rate = +\frac{1}{2} \frac{\Delta[O_{3}]}{ \Delta t} = -\frac{1}{3} \frac{\Delta[O_{2}]}{ \Delta t}$

$+\frac{\Delta[O_{3}]}{ \Delta t} = -\frac{2}{3} \frac{\Delta[-1.61 \cdot 10^{-5}]}{ \Delta t}$

$\frac{\Delta[O_{3}]}{ \Delta t} = 1.07 \cdot 10^{-5} \frac{mol}{Ls}$

So the rate of appearance of O₃ is 1.07x10⁻⁵ mol/Ls.

Have a nice day!

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