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RoseWind [281]
3 years ago
13

A 0.271 g sample of an unknown vapor occupies 294 ml at 140.°c and 847 mmhg. the empirical formula of the compound is ch2. what

is the molecular formula of the compound?
Chemistry
1 answer:
sdas [7]3 years ago
6 0
When the molar mass M = mass (g)/ no.of moles (Mol)

∴ moles= 0.271 g / M

By using the gas equation:

PV = n RT

when P is the pressure = 847 mmHg / 760 = 1.11 atm

V is the volume = 0.294 L

n = 0.271 / M

R is constant = 0.0821 

T= 140+273 = 413 K

so by substitution:

when n = PV/RT

∴ 0.271/ M = 1.11 atm *0.294 L/ 0.0821 *413

∴ M = 28 


when the empirical formula of CH2 = 12+2 = 14 

∴ the exact no.of moles = 28/14 = 2

∴the molecular formula = 2(CH2) = C2H4

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5. Which of the following has variable composition<br>A. Water<br>B. sugar<br>C, soil<br>D. Salt​
erica [24]

Answer:

C. Soil

Explanation:

The choice with variable composition is the soil. Soil have many different composition.

  • Soil is made up of minerals, organic matter , water and soil air.
  • Soil minerals are derived from weathered bedrock materials that have been broken down into small pieces.
  • Organic matter is derived from dead and decaying materials from plants and animals.
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7 0
3 years ago
What is the electron configuration of the element with 27 protons?
adelina 88 [10]
<span>The electronic configuration of cobalt is :1s2 2s2 2p6 3s2 3p6 3d7 4s2 </span>
7 0
3 years ago
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How can a piece of wood floating on water illustrate the condition of lowest potential energy and maximum
drek231 [11]

Answer:

By minimizing the height of the body's center of gravity relative to its center of buoyancy

Explanation:

In hydrostatics, the equilibrium state of a floating body relates to either a maximum or minimum of the potential energy.An equilibrium is stable when the potential energy is minimum.Minimizing the height of the floating body's center of gravity relative to its center of buoyancy attains a stable equilibrium configuration.

4 0
3 years ago
What volumes of 0.200 M HCOOH and 2.00 M NaOH would make 500. mL of a buffer with the same pH as one made from 475 mL of 0.200 M
Fed [463]

<u>36 ml of NaOh and</u><u> 464 ml</u><u> of </u><u>HCOOH</u><u> would be enough to form 500 ml of a buffer with the same pH as the buffer made with </u><u>benzoic acid </u><u>and NaOH.</u>

What is benzoic acid found in?

  • Some natural sources of benzoic acid include: ​Fruits:​ Apricots, prunes, berries, cranberries, peaches, kiwi, bananas, watermelon, pineapple, oranges.
  • ​Spices:​ Cinnamon, cloves, allspice, cayenne pepper, mustard seeds, thyme, turmeric, coriander.

Calculate the amount of moles in NaOH and benzoic acid. This calculation is done by multiplying molarity by volume.

Amount of moles of NaOH -2 × 0.025 =  0.05 mol

Amount of moles of benzoic acid 2 × 0.475 = 0.095 mol

In this case, we can calculate the pH produced by the buffer of these two reagents, as follows

pH = pKa + log\frac{base}{acid}

4.2 + log\frac{0.05}{0.045} = 4.245

We must repeat this calculation, with the values shown for HCOOH and NaOH. In this case, we can calculate as follows

pH = pKa + log\frac{base}{acid}

4.245 = 3.75 + log\frac{base}{acid}

log\frac{base}{acid} = 0.5

\frac{base}{acid} = 3.162

Now we must solve the equation above. This will be done using the following values

\frac{2(0.5 - x)}{0.2x - 2(0.5 - x)} = 0.464 L

With these values, we can calculate the volumes of NaOH and HCOOH needed to make the buffer.

NaOH volume

( 0.5 - 0.464)L

0.036L .................... 36ml

HCOOH volume

500 - 36 = 464mL

Learn more about benzoic acid

brainly.com/question/24052816

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3 0
2 years ago
The man responsible for discovering that the atom is mostly space is: Millikan Dalton Bohr Einstein Rutherford
kodGreya [7K]

Answer: Rutherford.


Explanation:


It was the scientist Ernest Rutherford who, by 1911, performed the gold foil experiment in which α particles were shoot to a thin foild of gold.


That experiment showed that although most α particles passed through the thin gold foild, some of them were deviated in small angles and some other were bounced backward.


The conclusion of the experiment was that the atom contained a small dense positively charged nucleous and negative particles (electrons) surroundiing the nucleous. Being the space in between the nucleous and the electrons empty.


Before Rutherford's experiment the model of the atom was that of the plum pudding presented by J.J Thomson, in which the atom was a solid positively charged sphere with embeded negative charge uniformly distributed in it.



7 0
3 years ago
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