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SpyIntel [72]
3 years ago
9

HELP ME PLEASE ASAP IVE POSTED THIS LIKE FIVE TIMES AND NO ONES RESPONDED PLEASE!!!!!!!!!!

Chemistry
2 answers:
skelet666 [1.2K]3 years ago
8 0

Answer:

ΔH=9.2 KJ

Explanation:

2NO₂→N₂O₄  ΔH=-57 KJ/mol

N₂ + O₂→2NO ΔH=180.6 KJ/mol

2NO + O₂→2NO₂ ΔH= -114.4 (notice this was reversed and sign changed

_____________________________________________

N₂+2O₂→N₂O₄ ΔH= 9.2 KJ

By reversing the third equation, we can get the O₂ on the left side or the (reactant side) so that we can get a total of 2O₂ in the final equation on the bottom. Cross out 2NO₂ on the first equation on the reactant side and 2NO₂ in equation 2 on the product side. You also want to cross out 2NO in the third equation on both the reactant and product side. This leaves the same above the line as below the line.

Since you reverse equation 3, the change in enthalpy will change sign so you input -57, 180.6 and -114.4 to get 9.2 KJ

Hope that helps.

frez [133]3 years ago
4 0
Im answering so this person can get Brainly
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PLEASE HELP ME WILL DO ANYTHING ‼️‼️
deff fn [24]

Answer:

In first shell 2 electrons are present and 7 electrons are present in last shell

Explanation:

6 0
3 years ago
Which of the following combinations would produce a neutralization reaction?
tresset_1 [31]

Answer:

it is option b

Explanation:

this is because neutralisation reaction takes place only between a base and an acid.

now, in OPTION A it is a neutral and base

OPTIONB  it is acid and base

OPTION C both are base

OPTION D  IT IS NOT POSSIBLE

7 0
3 years ago
A space air is at a temperature of 75 oF, and the relative humidity (RH) is 45%. Using calculations, find: (a) the partial press
earnstyle [38]

Answer:

A) Partial Pressure of dry air = 13.32 KPa

Partial Pressure of water vapour = 1.332 KPa

B) Humidity ratio; X = 0.0691

C) V_p = 0.8384 m³/Kg

Explanation:

A) We are given;

Temperature = 75°F

Relative Humidity = 45%

Now,to calculate the partial pressure, we will use the relationship;

Relative Humidity = (Partial Pressure/Vapour Pressure) × 100%

Making partial pressure the subject;

Partial Pressure = Relative Humidity × Vapour Pressure/100%

From the first table attached, at temperature of 75°F, the vapor pressure is 29.6 × 10^(-3) bar = 29.6 KPa

Thus;

Partial Pressure of dry air = (45 × 29.6)/100

Partial Pressure of dry air = 13.32 KPa

From online values, vapour pressure of water vapour at 75°F = 2.96 KPa

Thus;

Partial Pressure of water vapour = (45 × 2.96)/100 = 1.332 KPa

B) humidity ratio of moist air is given as;

X = 0.62198 pw / (pa - pw)  

where;

pw = partial pressure of the water vapor in moist air

pa = atmospheric pressure of the moist air

Thus;

X = (0.62198 × 1.332)/(13.32 - 1.332)  

X = 0.0691

C) Formula for moist air specific volume is;

V_p = (1 + (xRw/Ra) × RaT/p

Where;

V_p is specific volume

T is temperature = 75°F = 297.039 K

p is barometric pressure which in this case is standard sea level pressure = 101.325 KPa

pw is partial pressure of the water vapor in moist air = 1.332 KPa

Rw is individual gas constant for water = 0.4614 KJ/Kg.K

Ra is individual gas constant for air = 0.2869 KJ/Kg.K

V_p = (1 + (0.0691 * 0.4614/0.2869)) × 0.286.9 * 297.039/101.325

V_p = 0.8384 m³/Kg

6 0
3 years ago
How many moles are in 458 grams of na2so4
shtirl [24]

# moles = mass (g) / Mr (relative atomic mass)

# moles = 458 / ((23*2)+32+(16*4)

# moles= 458 /  142 = 3.2253521126760...

= 3.23 moles

5 0
3 years ago
Which of the following variables has the least effect on the rate a substance dissolved in a container of water?
Lelechka [254]
I think it’s A. The force of the stirring
4 0
3 years ago
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