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2 years ago

Use the table to calculate ΔH°rnx for the following reaction

Chemistry

1 answer:

alexdok [17]2 years ago

7 0

Answer:

The answer to your question is ΔH° rxn = -1343.9 kJ/mol

Explanation:

P₄O₆ (s) + 2 O₂ (g) ⇒ P₄O₁₀

ΔH°rxn = ?

Formula

ΔH°rxn = ∑H° products - ∑H° reactants

H° P₄O₆ = -1640.1 kJ/mol

H° O₂ = 0 kJ/mol

H° P₄O₁₀ = -2984 kJ/mol

-Substitution

ΔH° rxn = (-2984) - (-1640.1) - (0)

-Simplification

ΔH° rxn = -2984 + 1640.1

ΔH° rxn = -1343.9 kJ/mol

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What is the empirical formula of the compound with the molecular formula c18h36?

emmasim [6.3K]

When we write a formula of a compound in its simplest form, it is empirical formula.
Given the molecular formula is = C₁₈H₃₆
Now we can relate both empirical and molecular formula as;
Molecular formula = n x empirical formula
C₁₈H₃₆ = 18 x CH₂
So the empirical formula of C₁₈H₃₆ is CH₂

6 0

3 years ago

HELP QUICK ILL GIVE YOU BRAINLIEST AND 25 POINTS! bromine (br) has four energy levels. name 2 other elements that would have fou

Temka [501]

Answer:

titanium and potassium

Explanation:

6 0

3 years ago

Read 2 more answers

A quantity of NaCl was dissolved in 100 cm of solution to obtain

soldi70 [24.7K]

Answer:

2.93g

Explanation:first, let us calculate the number of mole of NaCl present in the solution. This is illustrated below:

Molarity = 0.5M

Volume = 100cm^3 = 100/1000 = 0.1L

Mole =?

Molarity = mole /Volume

Mole = Molarity x Volume

Mole of NaCl = 0.5 x 0.1 = 0.05mole

Now we can obtain the mass of NaCl as follows:

Molar Mass of NaCl = 23 + 35.5 = 58.5g/mol

Mole of NaCl = 0.05mol

Mass of NaCl =?

Mass = number of mole x molar Mass

Mass of NaCl = 0.05 x 58.5

Mass of NaCl = 2.93g

7 0

3 years ago

Ultraviolet radiation and radiation of shorter wavelengths can damage biological molecules because they carry enough energy to b

Alja [10]

Answer:

439.7nm

Explanation:

Energy of a quantum can be calculated using below formula

E=hv...........eqn(1)

But v=λ/ c .........eqn(2)

If we substitute eqn(2) into eqn(1) we have

E= hc/(λ)

Where E= energy

h= Plank's constant= 6.62607004 × 10-34 m2 kg / s

c= speed of light

c= 2.998 × 10^8 m/s

λ= wavelength= ?

But the energy was given in Kj , it must be converted to Kj/ photon for unit consistency.

Energy E= 272 kJ/mol × 1mol/6.02× 10^23

Energy= 451.83× 10^-24 Kj/ photon

E= hc/(λ)...........eqn(1)

If we make λ subject of the formula

λ= hc/E

Then substitute the values we have

λ= [(6.626 × 10^-34) × (2.998 × 10^8)]/451.83× 10^-24

λ=(0.00043965) × (1Kj/1000J) × (10^9nm/1m)

λ=439.7nm

Hence, the longest wavelength of radiation with enough energy to break carbon-sulfur bonds is 439.7nm

4 0

2 years ago

A 13.5g sample of gold is heated, then placed in a calorimeter containing 60g of water. The temperature of water increases from

sweet-ann [11.9K]

Answer:

$T_i~=163.1$ ºC

Explanation:

We have to start with the variables of the problem:

Mass of water = 60 g

Mass of gold = 13.5 g

Initial temperature of water= 19 ºC

Final temperature of water= 20 ºC

Initial temperature of gold= Unknow

Final temperature of gold= 20 ºC

Specific heat of gold = 0.13J/gºC

Specific heat of water = 4.186 J/g°C

Now if we remember the heat equation:

$Q_H_2_O=m_H_2_O*Cp_H_2_O*deltaT$

$Q_A_u=m_A_u*Cp_A_u*deltaT$

We can relate these equations if we take into account that all heat of gold is transfer to the water, so:

$m_H_2_O*Cp_H_2_O*deltaT=~-~m_A_u*Cp_A_u*deltaT$

Now we can put the values into the equation:

$60~g*4.186~J/g{\circ}C*(20-19)~{\circ}C=-(13.5~g*0.13~J/g{\circ}C*(20-T_i)~{\circ}C)$

Now we can solve for the initial temperature of gold, so:

$T_i~=(\frac{60~g*4.186~J/g{\circ}C*(20-19)~{\circ}C}{13.5~g*0.13~J/g{\circ}C})+20$

$T_i~=163.1$ ºC

I hope it helps!

5 0

3 years ago