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1 year ago

How many moles of n2(g) would contain exactly 4.0 moles of nitrogen atoms?

2 answers:

4 0

Each nitrogen molecule had 2 Nitrogen atoms.
So 2 moles of nitrogen gas molecules will have 4 moles of nitrogen atoms.Answer is 2moles

kaheart [24]1 year ago

4 0

Answer : The number of moles of $N_2$ contains are, 2 moles.

Explanation : Given,

Moles of nitrogen atoms = 4 moles

First we have to calculate the number of nitrogen atoms.

As, 1 mole of nitrogen atom contains $6.022\times 10^{23}$ number of nitrogen atoms

So, 4 mole of nitrogen atom contains $4\times 6.022\times 10^{23}$ number of nitrogen atoms

Now we have to calculate the moles of $N_2$ atoms.

As, $2\times 6.022\times 10^{23}$ number of nitrogen atoms present in 1 mole of $N_2$ atoms

As, $4\times 6.022\times 10^{23}$ number of nitrogen atoms present in $\frac{4\times 6.022\times 10^{23}}{2\times 6.022\times 10^{23}}=2$ mole of $N_2$ atoms

Therefore, the moles of $N_2$ atoms contains are, 2 moles

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One crystalline form of silica (SiO2) has a cubic unit cell, and from X-ray diffraction data it is known that the cell edge leng

Sav [38]

Answer:

8 Silicon atom are present in unit cell.

16 oxygen atoms are present unit cell.

Explanation:

Number of atoms in unit cell = Z =?

Density of silica = tex]2.32 g/cm^3[/tex]

Edge length of cubic unit cell = a = 0.700 nm = $0.700\times 10^{-7} cm$

$1 nm=10^{-7} cm$

Molar mass of Silica = $28.09 g/mol+16.00\times 2=60.09 g/mol$

Formula used :

$\rho=\frac{Z\times M}{N_{A}\times a^{3}}$

where,

$\rho$ = density

Z = number of atom in unit cell

M = atomic mass

$(N_{A})$ = Avogadro's number

a = edge length of unit cell

On substituting all the given values , we will get the value of 'a'.

$2.32 g/cm3=\frac{Z\times 60.09 g/mol}{6.022\times 10^{23} mol^{-1}\times (0.700\times 10^{-7}cm)^{3}}$

$Z = 8$

1 silicon is 2 oxygen atoms. then 8 silicon atoms will be 16 oxygen atoms.

5 0

2 years ago

B5H9(l) is a colorless liquid that will explode when exposed to oxygen. How much heat is released when 0.211 mol of B5H9 reacts

n200080 [17]

Answer:

Heat realesed is - 2192.7 kJ

Explanation:

First lets have the chemical equation balanced, and then solve the question based on the fact that the enthalpy change for a reaction is the sum of the enthalpies of formation of products minus reactants.

B₅H₉ (l) + O₂ (g) ⇒ B₂O₃ (s) + H₂O(l)

B atoms we have 5 reactants and 2 products, so the common mltiple is 10 and we have

2 B₅H₉ (l) + O₂ (g) ⇒ 5 B₂O₃ (s) + H₂O(l)

Now balance H by multiplying by 9 the H₂O

2 B₅H₉ (l) + O₂ (g) ⇒ 5 B₂O₃ (s) + 9 H₂O(l)

Finally, balance the O since we have 24 in products by multiplying by 12 the

O₂ ,

2 B₅H₉ (l) + 12 O₂ (g) ⇒ 5 B₂O₃ (s) + 9 H₂O

ΔHrxn = 5 x ΔHºf B₂O₃ + 9 x ΔHºf H₂O - ( 2 x ΔHºf B₅H₉ + 12 x ΔHºf O₂ )

We have all the ΔHºf s except oxygen but remember the enthalpy of formation of a pure element in its standard estate is cero.

ΔHrxn = 5 mol x ( -1272 kJ/mol )+ 9 mol x ( -285.4 kJ/mol ) - ( 2mol x 732 kJ/mol )

= -8928.6 kJ - 1464 kJ = -10,392 kJ

Now this enthalpy change was based in 2 mol reacted according to the balanced equation, so for 0.211 mol of B₅H₉ we will have:

-10,392 kJ/ 2 mol B₅H₉ x 0.211 mol B₅H₉ = - 2192.7 kJ

8 0

1 year ago

Read 2 more answers

When 2.36g of a nonvolatile solute is dissolved in 100g of solvent, the largest change in freezing point will be achieved when t

nignag [31]

Answer:

Option c → Tert-butanol

Explanation:

To solve this, you have to apply the concept of colligative property. In this case, freezing point depression.

The formula is:

ΔT = Kf . m . i

When we add particles of a certain solute, temperature of freezing of a solution will be lower thant the pure solvent.

i = Van't Hoff factor (ions particles that are dissolved in the solution)

At this case, the solute is nonvolatile, so i values 1.

ΔT = Difference between fussion T° of pure solvent - fussion T° of solution.

T° fussion paradichlorobenzene = 56 °C

T° fussion water = 0°

T° fussion tert-butanol = 25°

Water has the lowest fussion temperature and the paradichlorobenzene has the highest Kf. But the the terbutanol, has the highest Kf so this solvent will have the largest change in freezing point, when all the molalities are the same.

3 0

2 years ago

The hydrogen and oxygen atoms of a water molecule are held together by ________ bonds. The hydrogen and oxygen atoms of a water

Aleksandr [31]

Answer: HYDROGEN BONDS

Explanation:

Water molecules attract each other happily thanks to their polarity. A hydrogen atom plus end associates an oxygen atom minus end.

These attractions are an example of hydrogen bonds, weak interactions forming between a partially positive charged hydrogen and a more electronegative atom like oxygen. The hydrogen atoms involved in bonding with hydrogen need to be bound to electronegative atoms such as Oxygen and fluorine

3 0

1 year ago

Read 2 more answers

A different student is given a 10.0g sample labeled CaBr2 that may contain an inert (nonreacting) impurity. Identify a quantity

grandymaker [24]

Answer:

Mass of Ca in sample, Mass of Br in sample, Number of moles of Ca in sample, Number of moles of Br in sample, Mass or moles of element other than Ca or Br in sample

Explanation:

The AP Classroom will not count your answer to this question as correct unless it includes at least one of the answers listed above. If you say that theanswer to this question is density, it will be marked as incorrect, I found that out the hard way when I used the answers that brainly gave me.

Good luck,

I applaud you for using the sources avalible to you, which is /definetly not/ cheeting.

8 0

1 year ago