The compressed spring has elastic potential energy. If it is allowed to de-compress, the elastic potential energy will be converted to kinetic energy.

8 0

3 years ago

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Based on the equation, how many grams of Br2 are required to react completely with 72.4 grams of AlCl3

svlad2 [7]

Answer: 131 g of bromine is required.

Explanation:

The balanced equation will be :

$2AlCl_3+3Br_2\rightarrow 2AlBr_3+3Cl_2$

To calculate the moles, we use the equation:

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

moles of $AlCl_3$

$\text{Number of moles}=\frac{72.4g}{133g/mol}=0.544moles$

According to stoichiometry :

2 moles of $AlCl_3$ require = 3 moles of $Br_2$

Thus 0.544 moles of $AlCl_3$ require= $\frac{3}{2}\times 0.544=0.816moles$ of $Br_2$

Mass of $Br_2=moles\times {\text {Molar mass}}=0.816moles\times 160g/mol=131g$

Thus 131 g of bromine is required.

5 0

2 years ago

A nonvolatile organic compound Z was used to make up a solution. Solution A contains 6.00 g of Zdissolved in 100 g of waterand h

olya-2409 [2.1K]

Answer:

Molar mass of Z in solution A is 148.2 g/mol.

Explanation:

To solve this, we need to use colligative property about vapor pressure.

In any ideal solution, the vapor pressure of solution is lower than vapor pressure of pure solvent. Formula is:

ΔP = P° . Xm

ΔP = Vapor pressure of pure solvent - Vapor pressure of solution

At the normal boiling point of water (100°C), vapor pressure is 760 mmHg.

Let's replace in the formula, to find out Xm (mole fraction of solute)

760 mmHg - 754.5 mmHg = 760 mmHg . Xm

(760 mmHg - 754.5 mmHg) / 760 mmHg = Xm

Xm → 0.00724

Mole fraction of solute = moles of solute /total moles (st + sv)

In this case, our mole fraction will be

(6 g / MM) / ( (6 g/ MM + 100 g / 18g/mol) = 0.00724

Our unknown is MM (molar mass of Z). We solve the equation:

6 g / MM = 0.00724 . ((6 g/ MM + 100 g / 18g/mol))

6 g / MM = 0.04344 g /MM + 0.0402 g/mol

6 g/MM - 0.04344 g /MM = 0.0402 g/mol

5.95656 /MM = 0.0402 g/mol

5.95656 / 0.0402 g/mol = MM → 148.2 g/mol

4 0

3 years ago