Chemistry, 29.11.2019 01:31 estherboocx

Alculate the enthalpy of the reaction 4b(s)+3o2(g)→2b2o3(s) given the following pertinent information: b2o3(s)+3h2o(g)→3o2(g)+b2h6(g), δh∘a=+2035 kj 2b(s)+3h2(g)→b2h6(g), δh∘b=+36 kj h2(g)+12o2(g)→h2o(l), δh∘c=−285 kj h2o(l)→h2o(g), δh∘d=+4

Answers: 3

Show answers

Answers

Answer from: youugly0123

-2312 kJ

Explanation:

By the Hess Law, when a reaction is formed by several steps, the enthalpy change (ΔH) of the global reaction can be calculated by the sum of the enthalpy changes of the steps reactions.

Besides that, when a reaction is multiplied by a constant, ΔH must be multiplied by the same constant, and when the reaction is inverted, the signal of ΔH must be inverted.

B₂O₃(s) + 3H₂O(g) → 3O₂(g) + B₂H₆(g) ΔH = +2035 kJ (multiply by 2 and inverted)

2B(s) + 3H₂(g) → B₂H₆(g) ΔH = +36 kJ (multiply by 2)

H₂(g) + 1/2O₂(g) → H₂O(l) ΔH = -285 kJ (multiply by 6 and inverted)

H₂O(l) → H₂O(g) ΔH = +4 kJ (multiply by 6 and inverted)

6O₂(g) + 2B₂H₆(g) → 2B₂O₃(s) + 6H₂O(g) ΔH = -4070 kJ

4B(s) + 6H₂(g) → 2B₂H₆(g) ΔH = +72 kJ

6H₂O(l) → 6H₂(g) + 3O₂(g) ΔH = +1710 kJ

6H₂O(g) → 6H₂O(l) ΔH = -24 kJ

Summing the equation, simplifying the equal terms in both sides:

4B(s) + 3O₂(g) → 2B₂O₃(s)

ΔH = -4070 + 72 + 1710 - 24

ΔH = -2312 kJ

Answer from: Quest

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1

0.44 / 0.09 = 4.8

mgco3-5h2o"

Answer from: Quest

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2

Another question on Chemistry

Chemistry, 22.06.2019 09:00

Which process does not require the presence of a physical substance in order to transfer heat? air in the atmosphere is heated by the ground. this warm air then rises, and cooler air falls. this is an example of what type of process? how is conduction different from radiation?

Answers: 1

Answer

Chemistry, 22.06.2019 11:30

Define a is a tiny pavket of energy

Answers: 1

Answer

Chemistry, 22.06.2019 14:30

What is the relationship between wind and ocean waves? question 17 options: wind moving at higher speeds will transfer more energy to the water, resulting in stronger waves. wind moving at higher speeds will transfer energy over a larger part of the ocean water, resulting in waves with a shorter wavelength. winds moving at higher speeds with cause water to move forward at faster rates, causing larger ocean waves. winds moving at higher speeds will affect deeper water, resulting in waves that move at a faster rate. how do temperature and salinity affect deepwater currents? question 15 options: as temperatures and salinity levels of water increase, the water rises to the surface where it creates currents as it moves to colder regions. they create changes in wind direction, moving denser water in the same direction as the wind and causing the deepwater circulation patterns found in the ocean. they equalize the forces on undersea currents caused by the coriolis effect as they replace more dense water with less dense water. they create density differences that cause dense deepwater currents to flow toward the equator where they displace less dense, warmer water above them.

Answers: 2

Answer

Chemistry, 22.06.2019 21:30

8. what happens to matter during a chemical reaction

Answers: 1

Answer

You know the right answer?

Alculate the enthalpy of the reaction 4b(s)+3o2(g)→2b2o3(s) given the following pertinent informatio...

Questions