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You have 50 ml of a complex mixture of weak acids that contains some HF (pKa = 3.18) and some HCN (pKa = 9.21). Which is larger,

telo118 [61]

Answer:

$\frac{[F^{-}]}{[HF]}$ is larger

Explanation:

$pK_{a}=-logK_{a}$ , where $K_{a}$ is the acid dissociation constant.

For a monoprotic acid e.g. HA, $K_{a}=\frac{[H^{+}][A^{-}]}{[HA]}$ and $\frac{[A^{-}]}{[HA]}=\frac{K_{a}}{[H^{+}]}$

So, clearly, higher the $K_{a}$ value , lower will the the $pK_{a}$

In this mixture, at equilibrium, $[H^{+}]$ will be constant.

$K_{a}$ of HF is grater than $K_{a}$ of HCN

Hence, $(\frac{F^{-}}{[HF]}=\frac{K_{a}(HF)}{[H^{+}]})>(\frac{CN^{-}}{[HCN]}=\frac{K_{a}(HCN)}{[H^{+}]})$

So, $\frac{[F^{-}]}{[HF]}$ is larger

8 0

4 years ago

Haley has been having difficulty breathing. She is having difficulty with the gas exchange in the respiratory system. Which orga

Aleksandr-060686 [28]

Answer:

Lungs.

Explanation:

This is because the lungs are respiratory organs in the body that are located at the either side of the thorax or chest. These are organs that are incharge of exchange of gases. The air is breathe in through the trachea i.e oxygen is inhaled and carbondioxide which is the waste product is exhaled. Gas exchange take place in the lungs.

8 0

3 years ago

Call each of your flowers as water employee increase rate of growth

IceJOKER [234]

Okay ...................x

4 0

3 years ago

A student measures the mass of an 8 cm block of brown sugar to be 12.9 g. What is the density of

horrorfan [7]

Answer:

0.0025g/cm³

Explanation:

Given parameters:

Mass of the brown sugar = 12.9g

dimension of the sugar = 8cm

unknown:

density of the sugar = ?

Solution

Density is defined as the mass per unit volume of a substance. The expression is given below:

Density = $\frac{mass}{volume}$

We know the mass of the substance but the volume is unknown:

Volume of the brown sugar = l x bx h = 8x8x8 = 512cm³

Density of the brown sugar = $\frac{12.9}{512}$ = 0.0025g/cm³

8 0

3 years ago

Notice that "SO4" appears in two different places in this chemical equation. SO42− is a polyatomic ion called "sulfate." What nu

masya89 [10]

Answer : The number placed in front of $CuSO_4$ should be, three (3).

Explanation :

Balanced chemical reaction : It is defined as the number of atoms of individual elements present on reactant side must be equal to the product side.

The given unbalanced chemical reaction is,

$CaSO_4+AlCl_3\rightarrow CaCl_2+Al_2(SO_4)_3$

This chemical reaction is an unbalanced reaction because in this reaction, the number of atoms of chloride and sulfate ion are not balanced.

In order to balanced the chemical reaction, the coefficient 3 is put before the $CuSO_4$ , the coefficient 2 is put before the $AlCl_3$ and the coefficient 3 is put before the $CaCl_2$ .

Thus, the balanced chemical reaction will be,

$3CaSO_4+2AlCl_3\rightarrow 3CaCl_2+Al_2(SO_4)_3$

Therefore, the number placed in front of $CuSO_4$ should be, three (3).

5 0

4 years ago