chemistry and balanced equations

Question

Cisplatin, Pt(NH₃)₂Cl₂, is a drug that revolutionized the treatment of certain cancers. It is prepared according to the balanced equation below.

K₂Pt₂Cl₄ + 2 NH₃ ----> Pt(NH₃)₂Cl₂ + 2KCl

If 10.0 grams of K₂Pt₂Cl₄ is reacted completely, how much cisplatin Pt(NH₃)₂Cl₂ Will be produced (in grams)?

Answer 1

To solve this, we will need to do some stoichiometry.

We are going to go from grams of K₂Pt₂Cl₄ to grams of Pt(NH₃)₂Cl₂, but to get there we have to convert grams of the reactant to moles of the reactant, then compare the number of moles of the reactant to the number of moles of the product, and then finally convert the number of moles of the product to the number of grams of the product.

Remember that you will need the molar mass of the reactant and the product. Get it from the Periodic Table of the Elements by adding up the atomic masses of each atom in the molecule. Don't forget to count the number of atoms.

We aren't worried about the ammonia or the potassium chloride in this problem, so we can ignore that reactant (ammonia) and that product (potassium chloride).

Like this:

10 g K₂Pt₂Cl₄ x 1 mol K₂Pt₂Cl₄ / 610.156 g x 1 mol Pt(NH₃)₂Cl₂ / 1 mol K₂Pt₂Cl₄ x 300.042 g Pt(NH₃)₂Cl₂ / 1 mol Pt(NH₃)₂Cl₂ = 4.9 g Pt(NH₃)₂Cl₂