All categories

2 years ago

A scientist measures the standard enthalpy change for the following reaction to be -139.5 kj :

Chemistry

1 answer:

jeyben [28]2 years ago

7 0

Answer:

A scientist measures the standard enthalpy change for the following reaction to be -139.5 kj :

h2(g) + c2h4(g)c2h6(g)

based on this value and the standard enthalpies of formation for the other substances, the standard enthalpy of formation of c2h4(g) is _____ kj/mol

Explanation:

Hydrogen ΔHof (kJ/mol) ΔGof (kJ/mol) So (J/mol K)

H2 (g)

130.7

Carbon ΔHof (kJ/mol) ΔGof (kJ/mol) So (J/mol K)

C2H6 (g)

-84.7

-32.8

229.6

You might be interested in

The system co2(g) + h2(g) ⇀↽ h2o(g) + co(g) is at equilibrium at some temperature. at equilibrium a 4.00 l vessel contains 1.00

Marina CMI [18]

Answer: The moles of $CO_2$ added to the system is 7.13 moles

Explanation:

We are given:

Moles of $CO_2$ at equilibrium = 1.00 moles

Moles of $H_2$ at equilibrium = 1.00 moles

Moles of $H_2O$ at equilibrium = 2.40 moles

Moles of $CO$ at equilibrium = 2.40 moles

Volume of the container = 4.00 L

Concentration is written as:

$\text{Molarity}=\frac{\text{Moles}}{\text{Volume (in L)}}$

The given chemical equation follows:

$CO_2(g)+H_2(g)\rightleftharpoons H_2O(g)+CO(g)$

The expression of $K_c$ for above equation follows:

$K_c=\frac{[CO][H_2O]}{[CO_2][H_2]}$

Putting values in above equation, we get:

$K_c=\frac{(\frac{2.40}{4.00})\times (\frac{2.40}{4.00})}{(\frac{1.00}{4.00})\times (\frac{1.00}{4.00})}\\\\K_c=5.76$

To calculate the number of moles for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$

Molarity of CO = 0.791 mol/L

Volume of solution = 4.00 L

Putting values in above equation, we get:

$0.791M=\frac{\text{Moles of CO}}{4.00L}\\\\\text{Moles of CO}=(0.791mol/\times 4.00L)=3.164mol$

Extra moles of CO = (3.164 - 2.40) = 0.764 moles

Let the moles of $CO_2$ needed be 'x' moles.

Now, equilibrium gets re-established:

$CO_2(g)+H_2(g)\rightleftharpoons H_2O(g)+CO(g)$

Initial: 1.00 1.00 2.40 2.40

At eqllm: (0.236+x) 0.236 3.164 3.164

Again, putting the values in the expression of $K_c$ , we get:

$5.76=\frac{(\frac{3.164}{4.00})\times (\frac{3.164}{4.00})}{(\frac{0.236+x}{4.00})\times (\frac{0.236}{4.00})}\\\\5.76=\frac{10.011}{0.056+0.236x}\\\\x=7.13$

Hence, the moles of $CO_2$ added to the system is 7.13 moles

4 0

3 years ago

Need some help please?

VladimirAG [237]

26. B. 28. B. 20. A.

4 0

2 years ago

Hurry 60 points Can two green fish mate and have orange offspring? why or why not

Mademuasel [1]

Answer: Yes

Explanation:

This simulates the way offspring are formed by sperm from the male fish combining randomly with eggs from the female fish.

4 0

3 years ago

Read 2 more answers

Which represents the self ionization of water at 25 degrees

gayaneshka [121]

This question comes with four answer choices:

A. H2O + H2O ⇄ 2H2 + O2

B. H2O + H2O⇄ H2O2 + H2

C. H2O + H2O ⇄ 4H+ + 2O2-

D. H2O + H2O ⇄ H3O+ + OH-

Answer: option D. H2O + H2O ⇄ H3O+ + OH-

(the +sign next to H3O is a superscript, as well as the - sing next to OH)

Explanation:

The self-ionization of water, or autodissociation, produces the two ions H3O(+) and OH(-). The presence of ions is what explain the electrical conductivity of pure water.

In this, one molecule of H2O loses a proton (H+) (deprotonates) to become a hydroxide ion, OH−. Then, he hydrogen ion, H+, immediately protonates another water molecule to form hydronium, H3O+.

7 0

3 years ago

A cell needs to transport materials across the cell membrane. Which of the following best describes the type of transport shown

Klio2033 [76]

You need to add the picture so we can see

4 0

3 years ago