Change each percent abundance into decimal form by dividing by 100. Multiply this value by the atomic mass of that isotope. Add together for each isotope to get the average atomic mass.

Explanation:

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8 0

2 years ago

What two elements comprise most of a nebula? question 5 options: hydrogen and helium hydrogen and nitrogen oxygen and hydrogen c

OleMash [197]

hydrogen and helium and the most abundant elements in a nebula.

5 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]

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

<u>Explanation:</u>

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

How many moles of C2H2 are needed to react completely with 84 mol O2

Butoxors [25]

Balanced chemical equation:

2 C2H2 + 5 O2 = 4 CO2 + 2 H2O

2 moles C2H2 ---------------- 5 moles O2
moles C2H2 ------------------ 84 moles O2

moles C2H2 = 84 * 2 / 5

molesC2H2 = 168 / 5 => 33.6 moles of C2H2

4 0

3 years ago