Which statement about Niels Bohr’s atomic model is true?

Calculate how many grams of sodium azide (NaN3) are needed to inflate a 25.0 × 25.0 × 20.0 cm bag to a pressure of 1.35 atm at a

Luden [163]

Answer : The mass of $NaN_3$ at temperature $20^oC$ 28.47 g.

The mass of $NaN_3$ at temperature $10^oC$ 29.51 g.

Solution : Given,

Pressure of gas = 1.35 atm

Temperature of gas = $20^oC=273+20=293K$ $(0^oC=273K)$

Volume of gas = $25\times 25\times 20cm=12500cm^3=12.5L$ $(1L=1000cm^3)$

Molar mass of $NaN_3$ = 65 g/mole

Part 1 : First we have to calculate the moles of gas at temperature $20^oC$ . The gas produced in the given reaction is $N_2$ .

Using ideal gas equation,

$PV=nRT$

where,

P = pressure of the gas

V = volume of the gas

T = temperature of the gas

n = number of moles of gas

R = Gas constant = 0.0821 Latm/moleK

Now put all the given values in this formula, we get

$(1.35atm)\times (12.5L)=n\times (0.0821Latm/moleK)\times (293K)$

By rearranging the terms, we get the value of 'n'

$n=0.7015moles$

The moles of $N_2$ = 0.7015 moles

The given balanced reaction is,

$20NaN_3(s)+6SiO_2(s)+4KNO_3(s)\rightarrow 32N_2(g)+5Na_4SiO_4(s)+K_4SiO_4(s)$

As, 32 moles of $N_2$ produced from 20 moles of $NaN_3$

So, 0.7015 moles of $N_2$ produced from $\frac{20}{32}\times 0.7015=0.438$ moles of $NaN_3$

Now we have to calculate the mass of $NaN_3$ .

$\text{ Mass of }NaN_3=\text{ Moles of }NaN_3\times \text{ Molar mass of }NaN_3$

$\text{ Mass of }NaN_3=(0.438moles)\times (65g/mole)=28.47g$

Therefore, the mass of $NaN_3$ needed are 28.47 g.

Part 2 : We have to calculate the moles of gas at temperature $10^oC$ and same volume & pressure.

Using ideal gas equation,

$PV=nRT$

Now put all the given values in this formula, we get

$(1.35atm)\times (12.5L)=n\times (0.0821Latm/moleK)\times (283K)$

By rearranging the terms, we get the value of 'n'

$n=0.726moles$

The moles of $N_2$ = 0.726 moles

The given balanced reaction is,

$20NaN_3(s)+6SiO_2(s)+4KNO_3(s)\rightarrow 32N_2(g)+5Na_4SiO_4(s)+K_4SiO_4(s)$

As, 32 moles of $N_2$ produced from 20 moles of $NaN_3$

So, 0.726 moles of $N_2$ produced from $\frac{20}{32}\times 0.726=0.454$ moles of $NaN_3$

Now we have to calculate the mass of $NaN_3$ .

$\text{ Mass of }NaN_3=\text{ Moles of }NaN_3\times \text{ Molar mass of }NaN_3$

$\text{ Mass of }NaN_3=(0.454moles)\times (65g/mole)=29.51g$

Therefore, the mass of $NaN_3$ needed are 29.51 g.

7 0

4 years ago

PLZ SOMEONE HELP THANKS:))))<br> materials and conclude which is best to use. Full explanation

grin007 [14]

Answer:

For quick facts use reference materials such as encyclopedias, almanacs, or dictionaries. For credible and reputable information, use online databases of academic journals, or peer-reviewed journal articles that are written by scholars and researchers for a specific discipline.

3 0

3 years ago

Can someone help me I would really appreciate it

slega [8]

The condensed formula would be CH3-CH(CH4)-CH2-CH(CH4)-CH2-CH(CH4)-CH3. The molecular formula would be C10H25.

8 0

4 years ago

How many moles of h2o will be produced from 42.0 grams of h2o2

lisabon 2012 [21]

The answer is 44.6 mol

5 0

4 years ago

Read 2 more answers

Particle Mass

dimaraw [331]

Answer:

(i) Protons, Neutrons

(ii) Mass number = 15

(iii) Atomic number = 12

(iv) Neutrons present in the atom = 17

(v) Nuclear symbol for the silicon isotope with mass number, A = 29 is ²⁹₁₄Si

Explanation:

(i) An atom is composed of three fundamental sub-particles: electrons, protons and neutrons. Electrons are found in orbits or energy levels some distance away from The nucleus of the atom. The nucleus of an atom contains the protons and neutrons which accounts for the mass of the atom.

(ii) The mass number of an atom of an element is the sum of the protons and neutrons present jn the nucleus of the atom.

The mass number of an atom of oxygen with proton or atomic number 8 and neutron number 7 is 8 + 7 = 15

(iii) Atomic number of an atom of an element is equal to the number of protons in the atom of the element.

Mass number = proton number + neutron number

Proton number = mass number - proton number

Proton number = 25 - 13 = 12

(iv) In the atom of sulfur represented bymthe symbol, the number in superscript is the mass number A, and the number in subscript is the atomic number Z.

Mass number = proton number + neutron number

Neutron number = Mass number - proton number

Neutron number = 33 - 16 = 17

(v) The nuclear symbol for the silicon isotope with mass number, A = 29 is ²⁹₁₄Si

Where the number in superscript is the mass number A, and the number in subscript is the atomic number Z.

5 0

3 years ago