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Sonbull [250]
3 years ago
12

If a sample of nitrogen gas (N2) contains 1.2 x 10^24 atoms of nitrogen, then about how many moles of nitrogen gas are in the sa

mple?
5.0
1.0
2.5
3.0
Chemistry
1 answer:
OLga [1]3 years ago
4 0

The number of moles of nitrogen gas is  1.0 mole


<u><em>calculation</em></u>

N2 is a molecule  therefore;

1  molecule  of N₂  = 2 atoms  of N

          ? molecules= 1.2 x10 ²⁴atoms

<em>by cross  multiplication</em>

=[( 1.2  x 10²⁴ atoms x 1  molecule) / 2 atoms]  = 6 x 10²³  molecules


According to Avogadro's  law  1  mole  =6.02 x 10²³  molecules

                                                                ?  moles= 6.0 x 10²³   molecules

<em>by cross  multiplication</em>


= [(6.0x 10²³  molecules  x 1  mole) / 6.02 x10²³  molecules]  =  1.0  mole


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Mercury(II) oxide (HgO) decomposes to form mercury (Hg) and oxygen (O2). The balanced chemical equation is shown below. 2HgO Rig
BigorU [14]

Taking into account the reaction stoichiometry, the correct answer is the third option: 15.63 moles of HgO are needed to produce 250 g of O₂.

In first place, the balanced reaction is:

2 HgO  → 2 Hg + O₂

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

  • HgO: 2 moles
  • Hg: 2 moles
  • O₂: 1 moles  

The molar mass of the compounds is:

  • HgO: 216.59 g/mole
  • Hg: 200.59 g/mole
  • O₂: 32 g/mole  

Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:  

  • HgO: 2 moles× 216.59 g/mole= 433.18 grams
  • Hg: 2 moles× 200.59 g/mole= 401.18 grams
  • O₂: 1 mole× 32 g/mole= 32 grams

Then the following rule of three can be applied: if by reaction stoichiometry 32 grams of O₂ are produced by 2 moles of HgO, 250 grams of O₂ are produced from how many moles of HgO?

moles of HgO=\frac{250 grams of O_{2} x2 moles of HgO}{32grams of O_{2}}

<u><em>moles of HgO= 15.625 moles≅ 15.63 moles</em></u>

Finally, the correct answer is the third option: 15.63 moles of HgO are needed to produce 250 g of O₂.

Learn more about reaction stoichiometry:

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Selenium has six valence electrons. what is the valence of selenium
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<span>4; example selenium tetrafluoride SeF4, selenium dioxide SeO2 </span>
<span>2; example selenium difluoride SeF2, selenium dichloride SeCl2 </span>
<span>and -2; example hydrogen selenide H2Se</span>
8 0
4 years ago
If the crucible originally weighs 3.715 g and 2. 000 g of hydrate are added to it , what is the weight of the water that is lost
dimulka [17.4K]
For this, you need to know 1) the mass of the hydrate and 2) the mass of the anhydrous salt. Once you have both of these, you will subtract 1) from 2) to find the mass of the water lost.

From the problem, you know that 1) = 2.000 g.

Now you need to find 2). You know that your crucible+anhydrous salt is 5.022 g. To find just the anhydrous salt, subtract the mass of the crucible (3.715 g).

1) = 5.022 g - 3.715 g = 1.307 g

Now you can complete our original task.

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4 0
4 years ago
A sample of hydrogen gas has a pressure of 1.50 atm with a volume of 5.00 L, what is the pressure if the volume is expanded to 7
miss Akunina [59]

Answer:

The pressure is 0,97 atm

Explanation:

We apply Boyle Mariotte's Law, where for a certain mass of gas, at constant temperature, the pressure and volume vary inversely proportionally:            P1x V1 = P2 x V2 P2= (P1 x V1)/V2

P2 = 1, 50 atm x 5, 00 L /7,74 L

P2= 0, 97 atm

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3 years ago
For the separation of components of a mixture, we are following different methods. What is the condition in which the process of
soldier1979 [14.2K]

Answer:

The mixture 1/ must be homogeneous where there is one or more dissolved salts; 2/ should only contain one liquid component.

Explanation:

This method drives off the liquid components from the solid components. The process typically involves heating the mixture until no more liquid remains. Prior to using this method, the mixture should only contain one liquid component, unless it is not important to isolate the liquid components. This is because all liquid components will evaporate over time. This method is suitable to separate a soluble solid from a liquid.

Note : In many parts of the world, table salt is obtained from the evaporation of sea water. The heat for the process comes from the sun.

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Hope this answer can help you. Have a nice day!

4 0
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