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2 years ago

what mass of aluminium hydroxide is needed to decompose in order to produce 65.0 L of water at STP in stoichiometry?

Chemistry

2 answers:

pishuonlain [190]2 years ago

6 0

Aluminium Hydroxide on decomposition produces Al₂O₃ and Water vapors.

2 Al(OH)₃ → Al₂O₃ + 3 H₂O

According to equation at STP,

67.2 L (3 moles) of H₂O is produced by = 78 g of Al(OH)₃
So,
65.0 L of H₂O will be produced by = X g of Al(OH)₃

Solving for X,
X = (65.0 L × 78 g) ÷ 67.2 L

X = 75.44 g of Al(OH)₂
Result:
75.44 g of Al(OH)₂ is needed to decompose in order to produce 65.0 L of water at STP in stoichiometry

tatyana61 [14]2 years ago

5 0

Answer: The mass of aluminium hydroxide needed is 150.774 grams.

Explanation:

The chemical equation for the decomposition of aluminium hydroxide follows:

$2Al(OH)_3\rightarrow Al_2O_3+3H_2O$

At STP:

22.4 L of volume is occupied by 1 mole of a gas.

So, 65 L of volume will be occupied by = $\frac{1}{22.4L}\times 65L=2.9mol$

By Stoichiometry of the reaction:

3 moles of water is produced by 2 moles of aluminium hydroxide

So, 2.9 moles of water is produced by = $\frac{2}{3}\times 2.9=1.933mol$

To calculate the mass of aluminium hydroxide, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Number of moles of aluminium hydroxide = 1.933 moles

Molar mass of aluminium hydroxide = 78 g/mol

Putting values in above equation, we get:

$1.933mol=\frac{\text{Mass of aluminium hydroxide}}{78g/mol}\\\\\text{Mass of aluminium hydroxide}=150.774 grams$

Hence, the mass of aluminium hydroxide needed is 150.774 grams.

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$E$ stands for energy,
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The mass given is in the appropriate SI unit:

Mass is in kilograms.

Thus, proceed with the speed of light in SI units. The SI unit for speed is meters per second. For the speed of light, $c \approx \rm 3.00\times 10^{8}\;m\cdot s^{-1}$ .

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$\begin{aligned} E &= m \cdot c^{2} \\ &= \rm 5.81\times 10^{-29}\; kg \times {\left(3.00\times 10^{8}\; m\cdot s^{-1}\right)}^{2}\\ &\approx \rm 5.23\times 10^{-12}\;kg\cdot m^{2}\cdot s^{-2} \end{aligned}$ .

The unit of energy is not in joules. Don't be alerted. Consider the definition of a joule of energy. One joule is the work done on an object when a force of one newton acts on the object in the direction of the force through the distance of one meter. (English Wikipedia.)

$\rm 1\; J = 1\; N \times 1\; m$ .

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