Because of metallic bonding, when light is pointed at metals, they become

What mass of potassium hypochlorite (FW-90.6 g/mol) must be added to 4.50 x 10 mL of water to give a solution with pH 10.20? [Ka

marta [7]

Answer : The mass of potassium hypochlorite is, 4.1 grams.

Explanation : Given,

pH = 10.20

Volume of water = $4.50\times 10^2ml=0.45L$

The decomposition of KClO will be :

$KClO\rightarrow K^++ClO^-$

Now the further reaction with water $(H_2O)$ to give,

$ClO^-+H_2O\rightarrow HClO+OH^-$

First we have to calculate the pOH.

$pH+pOH=14\\\\pOH=14-pH\\\\pOH=14-10.20=3.8$

Now we have to calculate the $OH^-$ concentration.

$pOH=-\log [OH^-]$

$3.8=-\log [OH^-]$

$[OH^-]=1.58\times 10^{-4}M$

Now we have to calculate the base dissociation constant.

Formula used : $K_b=\frac{K_w}{K_a}$

Now put all the given values in this formula, we get :

$K_b=\frac{1.0\times 10^{-14}}{4.0\times 10^{-8}}=2.5\times 10^{-7}$

Now we have to calculate the concentration of $ClO^-$ .

The equilibrium constant expression of the reaction is:

$K_b=\frac{[OH^-][HClO]}{[ClO^-]}$

As we know that, $[OH^-]=[HClO]=1.58\times 10^{-4}M$

$2.5\times 10^{-7}=\frac{(1.58\times 10^{-4})^2}{[ClO^-]}$

$[ClO^-]=0.0999M$

Now we have to calculate the moles of $ClO^-$ .

$\text{Moles of }ClO^-=\text{Molarity of }ClO^-\times \text{Volume of solution}$

$\text{Moles of }ClO^-=0.0999mole/L\times 0.45L=0.0449mole$

As we know that, the number of moles of $ClO^-$ are equal to the number of moles of KClO.

So, the number of moles of KClO = 0.0449 mole

Now we have to calculate the mass of KClO.

$\text{Mass of }KClO=\text{Moles of }KClO\times \text{Molar mass of }KClO$

$\text{Mass of }KClO=0.0449mole\times 90.6g/mole=4.07g\approx 4.1g$

Therefore, the mass of potassium hypochlorite is, 4.1 grams.

6 0

3 years ago

If you see trapped bubbles ,you have to tap the cover slip using a

trapecia [35]

Answer:

?.............?...............

5 0

3 years ago

Calculate the theoretical yield of iron(III) oxide expected for this reaction if 0.50 mol of iron is reacted with excess oxygen

a_sh-v [17]

When you are dealing with mole calculations, whatever you do to one side of the equation you must also do to the other. .5Fe is 1/8th of 4Fe, so in order to determine what it will yield you must divide the given amount of Fe2O3 and divide THAT by 1/8th, leaving you with .25 mol of Fe2O3.

6 0

4 years ago

Compare the costs of using renewable resources to the costs of using nonrenewable resources.

Vitek1552 [10]

Answer:

Sample response:

The costs of using both renewable and nonrenewable resources depend on the extent of the use. If renewable resources are managed wisely, the use of the resource will not exceed the rate at which it is replenished. In this instance the cost of using renewable resources can be minimized, if not entirely eliminated. The cost of using nonrenewable resources is harder to minimize because nonrenewable resources cannot be replenished at the rate at which they are used. The environmental impact of using nonrenewable resources such as fossil fuels is greater than just the loss of the resource itself. Other impacts such as acid rain, global warming, and atmospheric pollution can result from the use of nonrenewable resources.

Explanation:

2021 edge

have a nice day

8 0

3 years ago

Read 2 more answers

Liters of a 2.40 M

kotykmax [81]

Answer:

1.42 L

Explanation:

Step 1:

The following data were obtained from the question :

Molarity of KBr = 2.40 M

Mole of KBr = 3.40 moles

Volume of solution =?

Step 2:

Determination of the volume of the solution.

Molarity of solution is simply the mole of the solute per unit volume the of solution. It is given as :

Molarity = mole /Volume

Volume = mole /Molarity

Volume = 3.4/2.4

Volume = 1.42 L

Therefore, the volume of the solution is 1.42 L

6 0

3 years ago