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Which of the following is true about a compound and its elements?

BaLLatris [955]

They can change properties completely
They can be separated
They form a new set of elements and compounds
<span>The elements become part of the original compounds</span>

6 0

4 years ago

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A 265-mL flask contains pure helium at a pressure of 751 torrs. A second flask with a volume of 465 mL contains pure argon at a

Nadya [2.5K]

Answer:

Total Pressure = 745.6 torr

Partial Pressure of He = 272.8 torr

Partial Pressure of Ar = 472.8 torr

Explanation:

Step 1: Data given

Volume of the flask helium = 265 mL

Pressure in the helium flask = 751 torr = 751/760 atm

Volume of the flask argon = 465 mL

Pressure in the argon flask = 727 torr = 727/760 atm

The total pressure exerted by a gaseous mixture is equal to the sum of the partial pressures of each individual component in a gas mixture.

Step 2: Calculate total volume

Total volume = 265 mL + 465 mL = 730 mL = 0.730 L

Step 3: Boyle's Law:

P1V1=P2V2

⇒ with P1 = total pressure gas exerts in its own flask

⇒ with V1 = volume of flask with stopcock valve closed

⇒ with P2 = partial pressure of gas exerts on total volume of both flasks when stopcock valve is opened

⇒ with V2 = total volume of both flasks with stopcock valve opened

Helium using Boyle's Law equation from above:

P1V1=P2V2

⇒ with P1 = Pressure of helium = 751 /760 = 0.98816 atm

⇒ with V1 = volume of helium = 0.265 L

⇒ with P2 = The new partial pressure of helium

⇒ with V2 = total volume = 0.730 L

(0.98816 atm)(0.265L)=P2(0.730L)

P2=0.359 atm

Argon using Boyle's Law equation from above:

P1V1=P2V2

⇒ with P1 = Pressure of argon = 727/760 = 0.95658 atm

⇒ with V1 = volume of argon = 0.465 L

⇒ with P2 = The new partial pressure of argon

⇒ with V2 = total volume = 0.730 L

(0.95658 atm)(0.465L)=P2(0.730L)

P2=0.609 atm

Step 4: Convert pressure in atm to torr

Pressure helium = 0.359 atm = 272.8 torr

Pressure argon = 0.609 atm = 472.8 torr

Step 5: Calculate Total pressure

Ptotal = P(He)+P(Ar)

⇒ Pt = total pressure of the gas mixture

⇒ P(He) = partial pressure of Helium

⇒ P(Ar) = partial pressure of Argon

Pt = 272.8 torr + 472.8 torr

Pt = 745.6 torr

Total Pressure = 745.6 torr

Partial Pressure of He = 272.8 torr

Partial Pressure of Ar = 472.8 torr

5 0

4 years ago

How many elements are found in the following chemical equation? K + Cl → KCl A. 1 B. 2 C. 3 D. 0

Gnesinka [82]

K is Potassium
Cl is Chlorine
There are 2 elements.

5 0

3 years ago

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4 Nitrogen monoxide reacts with oxygen like this:

olga2289 [7]

a. mol O₂=0.5

b. volume O₂ = 25 cm³

c. i. the total volume of the two reactants = 75 cm³

c. ii. the volume of nitrogen dioxide formed = 50 cm³

<h3>Further explanation</h3>

Reaction

2NO(gas) + O₂(gas) ⇒ 2NO₂ (gas)

a.

mol NO = 1

From the equation, mol ratio NO : O₂ = 2 : 1, so mol O₂ :

$\tt \dfrac{1}{2}\times 1=0.5$

b.

From Avogadro's hypothesis, at the same temperature and pressure, the ratio of gas volume will be equal to the ratio of gas moles

Because mol ratio NO : O₂ = 2 : 1, so volume O₂ :

$\tt \dfrac{1}{2}\times 50~cm^3=25~cm^3$

c.

i. total volume of reactants : 25 cm³+ 50 cm³=75 cm³

ii. the volume of nitrogen dioxide formed :

mol ratio NO : NO₂ = 2 : 2, so volume NO₂ = volume NO = 50 cm³

6 0

3 years ago

Draw the Lewis structure for the compound with the formula COCl2COCl2. Use lines to show bonding electrons.

stira [4]

Answer : The Lewis-dot structure of $COCl_2$ is shown below.

Explanation :

Lewis-dot structure : It shows the bonding between the atoms of a molecule and it also shows the unpaired electrons present in the molecule.

In the Lewis-dot structure the valance electrons are shown by 'dot'.

The given molecule is, $COCl_2$

As we know that carbon has '4' valence electrons, chlorine has '7' valence electron and oxygen has '6' valence electrons.

Therefore, the total number of valence electrons in $COCl_2$ = 1(4) + 2(7) + 1(6) = 24

According to Lewis-dot structure, there are 8 number of bonding electrons and 16 number of non-bonding electrons.

6 0

4 years ago