contestada

19
Gold reacts with the elements in Group 7 of the periodic table.
0.175 g of gold reacts with chlorine.
The equation for the reaction is:
2 Au + 3 Cl2 - 2 AuCla
Calculate the mass of chlorine needed to react with 0.175 g of gold.
Give your answer in mg
Relative atomic masses (Ar): Cl = 35.5 Au = 197

Respuesta :

Answer: The mass of chlorine gas required is 94.6 mg

Explanation:

The number of moles is defined as the ratio of the mass of a substance to its molar mass.

The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)

Given mass of gold = 0.175 g

Molar mass of gold = 197 g/mol

Plugging values in equation 1:

[tex]\text{Moles of gold}=\frac{0.175g}{197g/mol}=0.000888 mol[/tex]

The given chemical equation follows:

[tex]2Au+3Cl_2\rightarrow 2AuCl_3[/tex]

By the stoichiometry of the reaction:

If 2 moles of gold reacts with 3 moles of chlorine gas

So, 0.000888 moles of gold will react with = of chlorine gas

Molar mass of chlorine gas = 71 g/mol

Plugging values in equation 1:

[tex]\text{Mass of chlorine gas}=(0.001332mol\times 71g/mol)=0.0946g=94.6mg[/tex]       (Conversion factor: 1 g = 1000 mg)

Hence, the mass of chlorine gas required is 94.6 mg