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1 year ago

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A pure sample of bromine was vaporized and injected into a mass spectrometer and the data was plotted on the graph below. The ma

ss value for Br-79 is 78 918 amu Find the mass of Br-81.

1 answer:

Whitepunk [10]1 year ago

4 0

Answer:

$m_{Br-81}=80.945amu$

Explanation:

Hello,

In this case, since the percent abundance of Br-79 is 51.1% and that of the Br-81 is 48.9 %, we can write:

$m_{Br}=m_{Br-79}*51.1\%+m_{Br-81}*48.9\%$

Taking into account that the mass of bromine from the periodic table is 79.909 amu, the mass of Br-81 turns out:

$m_{Br-81}=\frac{m_{Br}-m_{Br-79}*51.1\%}{48.9\%} =\frac{79.909amu-78.918*0.511}{0.489} \\\\m_{Br-81}=80.945amu$

Best regards.

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An organic acid is composed of carbon (68.84%), hydrogen (4.96%), and oxygen (26.20%). Its molar mass is 122.12 g/mol. Determine

nekit [7.7K]

Answer:

The molecular formula of the compound is $C_{7}H_{6}O_{2}$ .

Explanation:

Let consider that given percentages are mass percentages, so that mass of each element are determined by multiplying molar massof the organic acid by respective proportion. That is:

Carbon

$m_{C} = \frac{68.84}{100}\times \left(122.12\,\frac{g}{mol} \right)$

$m_{C} = 84.067\,g$

Hydrogen

$m_{H} = \frac{4.96}{100}\times \left(122.12\,\frac{g}{mol} \right)$

$m_{H} = 6.057\,g$

Oxygen

$m_{O} = \frac{26.20}{100}\times \left(122.12\,\frac{g}{mol} \right)$

$m_{O} = 31.995\,g$

Now, the number of moles ( $n$ ), measured in moles, of each element are calculated by the following expression:

$n = \frac{m}{M}$

Where:

$m$ - Mass of the element, measured in grams.

$M$ - Molar mass of the element, measured in grams per mol.

Carbon ( $m_{C} = 84.067\,g$ , $M_{C} = 12.011\,\frac{g}{mol}$ )

$n = \frac{84.067\,g}{12.011\,\frac{g}{mol} }$

$n = 7$

Hydrogen ( $m_{H} = 6.057\,g$ , $M_{H} = 1.008\,\frac{g}{mol}$ )

$n = \frac{6.057\,g}{1.008\,\frac{g}{mol} }$

$n = 6$

Oxygen ( $m_{O} = 31.995\,g$ , $M_{O} = 15.999\,\frac{g}{mol}$ )

$n = \frac{31.995\,g}{15.999\,\frac{g}{mol} }$

$n = 2$

For each mole of organic acid, there are 7 moles of carbon, 6 moles of hydrogen and 2 moles of oxygen. Hence, the molecular formula of the compound is:

$C_{7}H_{6}O_{2}$

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1 year ago

Check all the boxes that describe the electron sea model. It is the simplest metal bonding model. It is the most complicated met

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Answer:

Another view could be from this definition: (Electron Sea Model) : The metallic bond consists of a series of metals atoms that have all donated their valence electrons to an electron cloud that permeates the structure. This electron cloud is frequently referred to as an electron sea. It might help to visualize the electron sea model as if it were a box of marbles that are surrounded by water. The marbles represent the metal atoms and the water represents the electron sea.

Explanation:

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2 years ago

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Answer:

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Explanation:

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So, fraction of original pressure = $\frac{1}{2}^2$

n here is number of half life

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Answer:

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X = 6.0 * 10∧12 cells / 6.022 * 10∧23 cells

X = 9,963 * 10∧-12 moles of cells per person

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2 years ago

A mixture of three gases has a total pressure at 298 K of 1560 mm Hg. the mixture is analyzed and is found to contain 1.50 mol N

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Partial Pressure of Xe=452.4mmHg

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1 year ago