Aluminum sulfide reacts with water to form aluminum hydroxide and hydrogen sulfide. (a) Write the balanced chemical equation for this reaction. (b) How many grams of aluminum hydroxide are obtained from 14.2 g of aluminum sulfide?

Verified step by step guidance

1. Step 1: Write the unbalanced chemical equation for the reaction. The reactants are aluminum sulfide (Al2S3) and water (H2O). The products are aluminum hydroxide (Al(OH)3) and hydrogen sulfide (H2S). So, the unbalanced equation is: Al2S3 + H2O -> Al(OH)3 + H2S
2. Step 2: Balance the chemical equation. The balanced equation is: Al2S3 + 6H2O -> 2Al(OH)3 + 3H2S. This means that one mole of aluminum sulfide reacts with six moles of water to produce two moles of aluminum hydroxide and three moles of hydrogen sulfide.
3. Step 3: Calculate the molar mass of aluminum sulfide and aluminum hydroxide. The molar mass of Al2S3 is approximately 150.16 g/mol and the molar mass of Al(OH)3 is approximately 78.00 g/mol.
4. Step 4: Convert the mass of aluminum sulfide given in the problem (14.2 g) to moles using its molar mass. This can be done using the formula: moles = mass (g) / molar mass (g/mol).
5. Step 5: Use the stoichiometry of the balanced equation to find the moles of aluminum hydroxide produced from the moles of aluminum sulfide. According to the balanced equation, two moles of Al(OH)3 are produced for every one mole of Al2S3. So, multiply the moles of Al2S3 by 2 to get the moles of Al(OH)3.
6. Step 6: Convert the moles of aluminum hydroxide to grams using its molar mass. This can be done using the formula: mass (g) = moles * molar mass (g/mol). This will give you the mass of aluminum hydroxide that can be obtained from 14.2 g of aluminum sulfide.

Key Concepts

Balancing Chemical Equations

Balancing chemical equations is essential to ensure that the law of conservation of mass is upheld, meaning the number of atoms of each element must be the same on both sides of the equation. This involves adjusting coefficients in front of the chemical formulas to achieve balance. For the reaction between aluminum sulfide and water, the balanced equation will reflect the correct stoichiometric relationships between reactants and products.

Stoichiometry

Stoichiometry is the quantitative relationship between reactants and products in a chemical reaction. It allows us to calculate the amounts of substances consumed and produced in a reaction based on the balanced equation. In this case, stoichiometry will be used to determine how many grams of aluminum hydroxide can be produced from a given mass of aluminum sulfide, using molar ratios derived from the balanced equation.

Molar Mass

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It is crucial for converting between grams and moles, which is necessary for stoichiometric calculations. To solve part (b) of the question, the molar masses of aluminum sulfide and aluminum hydroxide must be calculated to determine how many grams of aluminum hydroxide can be produced from the 14.2 g of aluminum sulfide.