Which of the following terms best describes an atom which is chemically unreactive?

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

2 years ago

“The chemical formula in the structure of phosphorus is shown below. This represents a(n)....”

den301095 [7]

Answer:

element made up of four (4) similar atoms.

Explanation:

An element is made up of one kind of atom. A compound is made up of 2 or more different kinds of atoms that are chemically together.

5 0

2 years ago

What type of reaction occurs in a hand warmer?<br> Exothermic<br> Endothermic

storchak [24]

Answer:

The reaction is exothermic.

Explanation:

8 0

2 years ago

Which is the following is a decomposition reaction

lora16 [44]

The equation that is a decomposition reaction is

PbCO3(s) ---> PbO(s) + CO2(g)

That is option D.

<h3>Properties of a decomposition reaction</h3>

A chemical reaction is defined as the combination of substances called reactants to form a product. The various types of chemical reaction include:

synthesis reaction

combustion reaction

decomposition reaction

single or double replacement reaction

Decomposition reaction is that type of chemical reaction in which the reactant breaks down to form two or more products.

Therefore the heating of lead (II) carbonate is a decomposition reaction.

Learn more about decomposition reaction here:

brainly.com/question/15229375

5 0

1 year ago

Where would you have the least weight?

Vikki [24]

In a place with no gravity

Explanation:

Weight is a force exerted by a body in the presence of gravity.

Weight = mass x gravity

Without gravity, there is no force of weight. The more the gravity, the more the weight of a body.

A body will experience weightlessness in a place without no gravity.

Therefore, one will experience the least weight in a place without the pull of gravity.

Learn more:

weight and mass brainly.com/question/5956881

#learnwithBrainly

8 0

3 years ago