Molten gallium reacts with arsenic to form the semiconductor, gallium arsenide, GaAsGaAs, used in light emitting diodes and solar cells: Ga (l) + As (s) → GaAs (s) Ga (l) + As (s) → GaAs (s) If 4.00 gg of gallium is reacted with 5.50 gg of arsenic how many grams of the excess reactant are left at the end of the reaction?

Question

Chemistry

Daniella Riddle

13 July, 18:11

Molten gallium reacts with arsenic to form the semiconductor, gallium arsenide, GaAsGaAs, used in light emitting diodes and solar cells: Ga (l) + As (s) → GaAs (s) Ga (l) + As (s) → GaAs (s) If 4.00 gg of gallium is reacted with 5.50 gg of arsenic how many grams of the excess reactant are left at the end of the reaction?

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Fernanda Avila · Answer 1

1.195 g of Arsenic.

Explanation:

Equation of the reaction:

Ga (l) + As (s) → GaAs (s).

Calculating the limiting reagent by:

Number of moles of:

Gallium:

Molar mass of Gallium = 69.7 g/mol.

Mass = 4 g

Number of moles = mass/molar mass

= 4/69.7

= 0.0574 mol.

Arsenic:

Molar mass of Arsenic = 75 g/mol.

Mass = 5.5 g

Number of moles = mass/molar mass

= 5.5/75

= 0.0733 mol

Therefore, using stoichiometry since 1 mole of Gallium reacted with 1 mole of Arsenic. The limiting reagent is Gallium.

Excess reagent is Arsenic.

Number of moles excess = 0.0733 - 0.0574

= 0.0159 moles

Mass of the excess Arsenic left =

Molar Mass * number of moles

= 0.0159 * 75

= 1.195 g of Arsenic.