Determing Valence Electrons

Which is the best example of a new substance forming?

Hunter-Best [27]

Answer:

lighting a match is the answer.

8 0

3 years ago

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The solubility product of PbI2 is 7.9x10^-9. What is the molar solubility of PbI2 in distilled water?

Agata [3.3K]

Answer: The molar solubility of $PbI_2$ is $1.25\times 10^{-3}mol/L$

Explanation:

Solubility is defined as the maximum amount of solute that can be dissolved in a solvent at equilibrium.

Solubility product is defined as the product of concentration of ions present in a solution each raised to the power its stoichiometric ratio.

The balanced equilibrium reaction for the ionization of calcium fluoride follows:

$PbI_2\rightleftharpoons Pb^{2+}+2I^-$

s 2s

The expression for solubility constant for this reaction will be:

$K_{sp}=[Pb^{2+}][I^-]^2$

We are given:

$K_{sp}=7.9\times 10^{-9}$

Putting values in above equation, we get:

$7.9\times 10^{-9}=(s)\times (2s)^2\\\\7.9\times 10^{-9}=4s^3\\\\s=1.25\times 10^{-3}mol/L$

Hence, the molar solubility of $PbI_2$ is $1.25\times 10^{-3}mol/L$

3 0

3 years ago

What is the correct formula for calcium sulfate dihydrate?

Murljashka [212]

Answer:

It is CaSO4.2H2O

Explanation:

Calcium has a valence of 2 because it has only two valency electrons.

Sulphate ( SO4)^2- is a radical with a valence value of 2.

When Calcium combines with sulphate in bonding,

Formular ==>  Ca2(SO4)2

But the 2 cancel out.

Overall formular==> CaSO4

For hydrated, ==> CaSO4.H2O

3 0

3 years ago

Which one of these statements about cell division is not accurate?

Masja [62]

The answer is b damaged tissue can not be repaired

7 0

3 years ago

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Trick to change word equation to chemical equation

Elden [556K]

Answer:

actually word equation has the names and we need to write molecular formula in chemical eqn. so I don't think there is sort of trick.You just need to memorise the molecular formula of chemicals.

6 0

3 years ago