Physical change does not make a new chemical/object. A chemical change does.

Chemical Change example: Combining liquid and liquid to create a new substance

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3 years ago

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The compound trimethylamine, (CH3)3N, is a weak base when dissolved in water. Write the Kb expression for the weak base equilibr

GREYUIT [131]

Answer:

The $K_b$ expression for the weak base equilibrium is:

$K_b=\frac{[(CH_3)_3NH^+][OH^-]}{[(CH_3)_3N]}$

Explanation:

$(CH_3)_3N(aq)+H_2O(l)\rightlefharpoons (CH_3)_3NH^++OH^-(aq)$

The expression of the equilibrium constant of base $K_c$ can be given as:

$K_c=\frac{[(CH_3)_3NH^+][OH^-]}{[(CH_3)_3N][H_2O]}$

] $K_b=K_c\times [H_2O]=\frac{[(CH_3)_3NH^+][OH^-]}{[(CH_3)_3N]}$

As we know, water is pure solvent, we can put $[H_2O]=1$

$K_b=K_c\times 1=\frac{[(CH_3)_3NH^+][OH^-]}{[(CH_3)_3N]}$

So, the the $K_b$ expression for the weak base equilibrium is:

$K_b=\frac{[(CH_3)_3NH^+][OH^-]}{[(CH_3)_3N]}$

6 0

3 years ago

The average atomic mass of copper is 63.55 amu. If the only two isotopes of copper have masses of 62.94 amu and 64.93 amu, what

IgorLugansk [536]

Explanation:

Let relative ratio of one isotope (62.94 u) be X

Then, relative ratio of other isotope (64.93) will be (1 - X)

Now,

(62.94)x + (64.93)(1 - x) = 63.55

1.99x = 1.38

X = 0.69

Relative Abundance :

(62.94 u) isotope = 69 %

(64.93 u) isotope = 31 %

7 0

3 years ago