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3 years ago

5

Calculate the average atomic mass of element X using the table below. Then use the periodic table to identify the element. Separ

ate your answers with a comma.

1 answer:

Ksenya-84 [330]3 years ago

4 0

Answer:

126.8, Iodine

Explanation:

mass ×abundance/100
(126.9045×80.45/100)+(126.0015×17.23/100)+(128.2230×2.23/100)
102.1+21.7+3=126.8

<em>IODINE</em><em> </em><em>has</em><em> </em><em>an</em><em> </em><em>atomic</em><em> </em><em>mass</em><em> </em><em>of</em><em> </em>126.8 or 126.9

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Rank the following solutions in order of increasing acidity (least acidic to most acidic): I: [H3O+] = 1x10−5 II: [OH−] = 1x10−1

kozerog [31]

Answer: option C) II < III < I

i.e [OH−] < [H3O+] < I

Explanation:

First, obtain the pH value of I and II, then compare both with III.

For I

Recall that pH = -log (H+)

So pH3O = -log (H3O+)

= - log (1x10−5)

= 4

For II

pOH = - log(OH-)

= - log(1x10−10)

= 9

For III

pH = 6

Since, pH range from 1 to 14, with values below 7 to be acidic, 7 to be neutral, above 7 to be alkaline: then, 9 < 6 < 4

Thus, the following solutions from least acidic to most acidic is II < III < I

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3 years ago

A 515cm^3 flask contains 0.460 g of a gas at a pressure of 153 kPa and a temperature of 322K. What is the molecular mass of this

erastovalidia [21]

Answer:

Molecular mass, $M=28.89\ \text{g/mol}$

Explanation:

Given that,

Mass of gas, m = 0.46 g

Volume of the container, V = 515 cm^3

Pressure, P = 153 kPa

Temperature, T = 322 K

We need to find the molecular mass of this gas. We know that,

PV =nRT

n = no of moles

$n=\dfrac{PV}{RT}\\\\n=\dfrac{153\ kPa\times 0.515\ L}{8.31447\ LkPaK^{-1}{mol^{-1}}\times (322+273)\ K }\\\\n=0.01592\ \text{moles}$

No of moles = mass/molecular mass

Let molecular mass is M

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So, the molecular mass of this gas is $28.89\ \text{g/mol}$

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Answer:

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Explanation:

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Diazomethane has the molecular formula CH2N2. Draw the preferred Lewis structure for diazomethane and assign formal charges to a

Alja [10]

Answer:

See explanation

Explanation:

We define the formal charge on an atom in a molecule as the charge it carries assuming that electrons in all chemical bonds of the molecule were shared equally between atoms irrespective of the electronegativity of each atom.

The formula for calculating the formal charge on an atom in a molecule is;

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The Lewis structure of the molecule is shown in the image attached.

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