In which of the following substances does a beam of light travel the fastest?

A family is another name for a<br> on the periodic table of elements.

topjm [15]

Answer:

A family in the periodic table is a group of related elements.

Explanation:

3 0

4 years ago

An aqueous solution of sodium fluoride is slowly added to a water sample that contains barium ion (2.75×10-2M ) and calcium ion

Alona [7]

Answer : The remaining concentration of the first ion to precipitate when the second ion begins to precipitate is, $1.07\times 10^{-6}M$

Explanation :

The dissociation of barium fluoride is written as:

$BaF_2\rightleftharpoons Ba^{2+}+2F^-$

The expression for solubility constant for this reaction will be,

$K_{sp}=[Ba^{2+}][F^-]^2$

As we know that at room temperature $25^oC$ the $K_{sp}$ of barium fluoride is, $1\times 10^{-6}$ .

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

$1\times 10^{-6}=(2.75\times 10^{-2})\times [F^-]^2$

$[F^-]=6.03\times 10^{-3}M=0.00603M$

The barium fluoride precipitate when fluoride ion is equal to 0.00603 M.

The dissociation of calcium fluoride is written as:

$CaF_2\rightleftharpoons Ca^{2+}+2F^-$

The expression for solubility constant for this reaction will be,

$K_{sp}=[Ca^{2+}][F^-]^2$

As we know that at room temperature $25^oC$ the $K_{sp}$ of calcium fluoride is, $3.90\times 10^{-11}$ .

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

$3.90\times 10^{-11}=(6.70\times 10^{-2})\times [F^-]^2$

$[F^-]=2.41\times 10^{-5}M=0.0000241M$

The calcium fluoride precipitate when fluoride ion is equal to 0.0000241 M.

Since, the fluoride ion concentration in calcium fluoride is less then the fluoride ion concentration in barium fluoride. That means, calcium fluoride will precipitate first.

Thus, the concentration $Ca^{2+}$ ion remaining at $F^-$ concentration (0.00603 M) is calculated as:

$K_{sp}=[Ca^{2+}][F^-]^2$

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

$3.90\times 10^{-11}=[Ca^{2+}]\times (0.00603)^2$

$[Ca^{2+}]=1.07\times 10^{-6}M$

Therefore, the remaining concentration of the first ion to precipitate when the second ion begins to precipitate is, $1.07\times 10^{-6}M$

3 0

3 years ago

The kinetic energy of all the particles in a given sample of matter is the different. Question 11 options: True False

GalinKa [24]

Answer is true I'm voting

6 0

4 years ago

A solution has a volume of 2.0 L and contains 36.0 grams of glucose (C6H12O6). If the molar mass of glucose is 180 g/mol, what i

zysi [14]

36.0 g of glucose divided by 180 g/mol = 0.200 moles of glucose

find molarity
0.200 moles of glucose / 2 liters = 0.100 molar solution

(hope this helps)

6 0

3 years ago

The chemical formula for a emerald is BeAl2(SiO3)6.<br> An emerald can be described as

grin007 [14]

Emerald can be described as a transparent, green coloured gem stone made up of mineral beryl together with trace amount of chromium or sometimes vanadium having chemical formula as $Be_3Al_2(SiO_3)_6$ .

<h3>
What is the significant of Emerald ?</h3>

Through time, the emerald has been known as a symbol of truth and love.

In ancient Greece and Rome, emerald was said to be the gemstone of the goddess Venus, purveyor of love and hope.

On the other side of the world, emeralds were revered by the Incas and believed by the Egyptians to be a source of eternal life.

Learn more about Gem stones here ;
brainly.com/question/14375301

#SPJ1

6 0

2 years ago