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3 years ago

Is a faded picture a chemical or physical change?

Chemistry

2 answers:

sweet-ann [11.9K]3 years ago

7 0

QUIMIC. (Química) :)

nalin [4]3 years ago

5 0

It is a chemical change

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Ñspent fuelî that can no longer be used to create energy.<br> nuclear waste ?

svetoff [14.1K]

Spent fuel that can no longer be used to create energy is waste.

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3 years ago

What is the measure of the efficiency of a chemical reaction? percent yield annual yield actual yield theoretical yield

artcher [175]

Answer:

Precent yield

Explanation:

This is takes into account how much of a substance should have been created (theoretical yield) and compares it to what was actually created (the actual yield).

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3 years ago

What is 25mg in grams

Viktor [21]

Kilo
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25 milligrams equal 0.025 grams

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3 years ago

The equilibrium constant Kc for the reaction PCl3(g) + Cl2(g) ⇌ PCl5(g) is 49 at 230°C. If 0.70 mol of PCl3 is added to 0.70 mol

Ymorist [56]

Answer : The correct option is, (B) 0.11 M

Solution :

First we have to calculate the concentration $PCl_3$ and $Cl_2$ .

$\text{Concentration of }PCl_3=\frac{\text{Moles of }PCl_3}{\text{Volume of solution}}$

$\text{Concentration of }PCl_3=\frac{0.70moles}{1.0L}=0.70M$

$\text{Concentration of }Cl_2=\frac{\text{Moles of }Cl_2}{\text{Volume of solution}}$

$\text{Concentration of }Cl_2=\frac{0.70moles}{1.0L}=0.70M$

The given equilibrium reaction is,

$PCl_3(g)+Cl_2(g)\rightleftharpoons PCl_5(g)$

Initially 0.70 0.70 0

At equilibrium (0.70-x) (0.70-x) x

The expression of $K_c$ will be,

$K_c=\frac{[PCl_5]}{[PCl_3][Cl_2]}$

$K_c=\frac{(x)}{(0.70-x)\times (0.70-x)}$

Now put all the given values in the above expression, we get:

$49=\frac{(x)}{(0.70-x)\times (0.70-x)}$

By solving the term x, we get

$x=0.59\text{ and }0.83$

From the values of 'x' we conclude that, x = 0.83 can not more than initial concentration. So, the value of 'x' which is equal to 0.83 is not consider.

Thus, the concentration of $PCl_3$ at equilibrium = (0.70-x) = (0.70-0.59) = 0.11 M

The concentration of $Cl_2$ at equilibrium = (0.70-x) = (0.70-0.59) = 0.11 M

The concentration of $PCl_5$ at equilibrium = x = 0.59 M

Therefore, the concentration of $PCl_3$ at equilibrium is 0.11 M

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3 years ago

What information is presented inside each square of the periodic table?

Verdich [7]

The symbol, the atomic mass, the number of protons and electrons

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3 years ago