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3 years ago

According to the following thermochemical equation, what mass of H2O (in g) must form in order to produce 488 kJ of energy?

Chemistry

1 answer:

vladimir1956 [14]3 years ago

7 0

Answer:

m = 95.47 g

Explanation:

The reaction is missing. I found it, and here's the missing part:

SiO2(s) + 4HF(s) -> SiF4(s) + 2H2O(l) ΔH°rxn = -184 kJ

According to the reaction, 2 moles of water are produced in this reaction, and this also produces 488 kJ of energy.

To calculate the mass of any compound we use the expression:

m = n*MM

The molar mass of water is 18 g/mol. so, we need the moles of water to get the mass. The relation between the heat and energy is the following:

ΔH = Q/n ---> solving for n:

n = Q/ΔH.

So, let's calculate moles of water used here:

n = 488 * 2/184

n = 5.304 moles

Now we can calculate the mass:

m = 5.304 * 18

m = 95.47 g

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One reaction involved in the conversion of iron ore to the metal is FeO(s) + CO(g) → Fe(s) + CO2(g) Use Hess’s Law to calculate

Ugo [173]

Answer:

$\delta H_{rxn} = -66.0 \ kJ/mole$

Explanation:

Given that:

$3FeO_3_{(s)}+CO_{(g)} \to 2Fe_3O_4_{(s)} +CO_{2(g)} \ \ \delta H = -47.0 \ kJ/mole -- equation (1) \\ \\ \\ Fe_2O_3_{(s)} +3CO_{(g)} \to 2FE_{(s)} + 3CO_{2(g)} \ \ \delta H = -25.0 \ kJ/mole -- equation (2) \\ \\ \\ Fe_3O_4_{(s)} + CO_{(g)} \to 3FeO_{(s)} + CO_{2(g)} \ \delta H = 19.0 \ kJ/mole -- equation (3)$

From equation (3) , multiplying (-1) with equation (3) and interchanging reactant with the product side; we have:

$3FeO_{(s)} + CO_{2(g)} \to Fe_3O_4_{(s)} + CO_{(g)} \ \delta H = -19.0 \ kJ/mole -- equation (4)$

Multiplying (2) with equation (4) ; we have:

$6FeO_{(s)} + 2CO_{2(g)} \to 2Fe_3O_4_{(s)} + 2CO_{(g)} \ \delta H = -38.0 \ kJ/mole -- equation (5)$

From equation (1) ; multiplying (-1) with equation (1); we have:

$2Fe_3O_4_{(s)} +CO_{2(g)} \to 3FeO_3_{(s)}+CO_{(g)} \ \ \delta H = 47.0 \ kJ/mole -- equation (6)$

From equation (2); multiplying (3) with equation (2); we have:

$3 Fe_2O_3_{(s)} +9CO_{(g)} \to 6FE_{(s)} + 9CO_{2(g)} \ \ \delta H = -75.0 \ kJ/mole -- equation (7)$

Now; Adding up equation (5), (6) & (7) ; we get:

$6FeO_{(s)} + 2CO_{2(g)} \to 2Fe_3O_4_{(s)} + 2CO_{(g)} \ \delta H = -38.0 \ kJ/mole -- equation (5)$

$2Fe_3O_4_{(s)} +CO_{2(g)} \to 3FeO_3_{(s)}+CO_{(g)} \ \ \delta H = 47.0 \ kJ/mole -- equation (6)$

$3 Fe_2O_3_{(s)} +9CO_{(g)} \to 6FE_{(s)} + 9CO_{2(g)} \ \ \delta H = -75.0 \ kJ/mole -- equation (7)$

$FeO \ \ \ + \ \ \ CO \ \ \to \ \ \ \ Fe_{(s)} + \ \ CO_{2(g)} \ \ \ \delta H = - 66.0 \ kJ/mole$

$\delta H_{rxn} = \delta H_1 + \delta H_2 + \delta H_3$ (According to Hess Law)

$\delta H_{rxn} = (-38.0 + 47.0 + (-75.0)) \ kJ/mole$

$\delta H_{rxn} = -66.0 \ kJ/mole$

8 0

3 years ago

Which Statements below are true?

yKpoI14uk [10]

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D. Distance is always greater than or equal to the magnitutde of the displacement.

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3 years ago

True or false: Driving a motor vehicle after taking substances which alter The central nervous system can have side effects whic

Norma-Jean [14]

True, because the substance basically reacts to the nervous system just like the anesthetic. Which can affect your decision making, and you might experience drowsiness, slow reaction time which is very risky for the driver and his/her surroundings.

Hope this helps :)

4 0

3 years ago

G.com what is the mass of a gold bar that is 7.379 × 10–4 m3 in volume

tiny-mole [99]

7.379 * 10^(-4) is measured, hence prone to error, either human error or via measuring device. In this case,
100 cm = 1 m is written in stone and is unquestionable.
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5 0

3 years ago

When solutions of magnesium chloride and potassium phosphate are combined write the formula for the precipitate formed

Zielflug [23.3K]

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3 years ago