problems

1.      Cisplatin, [Pt(NH₃)₂Cl₂], an anticancer agent used for treatment of solid tumor is prepared by the reaction of potassium tetrachloroplatinate(II), K₂[PtCl₄], with ammonia :

K₂[PtCl₄] + 2NH₃ à [Pt(NH₃)₂Cl₂] + 2KCl

            Assume that 10.0 g K₂[PtCl₄] and 10.0 g of NH₃  are allowed to react.

a.       Which reactant is limiting and which is excess?

b.      How many grams of the excess reactant are consumed and how many grams remain?

c.       How many grams of cisplatin are formed?

(K=39.1g/mol, Pt=195.1g/mol, Cl=35.5g/mol, N= 14 g/mol, H= 1 g/mol)

2.      Thiophene is a compound that composed from C, H and S elements. 7.96 mg thiophene footage is burned in oxygen produces 16.65 mg CO₂. Another footage of thiophene is reacted to convert sulfur into barium sulfate. if 4.31 mg thiophene produce 11.96 mg  barium sulfate, what is the empirical formula  of thiophene? if the relative molecular mass of thiophene is known 84 g/mol, determine the molecular formula of thiophene?

Answer :

1.       

First step            : determine the reacted mole of K₂[PtCl₄] and  NH₃

Second step        : determine which reactant is limiting and which reactant is excess

Third step           : determine the consumed mass of excess reactant by  multiply the molar mass of excess reactant with the mole of excess reactant. To determine how many mass remain substract the mass of excess reactant with its consumed mass of excess reactant

Fourth step         : determine the mass of cisplatin formed by multiply the molar mass of [Pt(NH₃)₂Cl₂]   with the mole of [Pt(NH₃)₂Cl₂].

2.      first step    : determine the mass percentage of each element

second step     : determine the mole ratio of the elements

third step         : determine the empirical formula of thiophene

second step     : determine the molecule formula of thiophene

3.      Cisplatin, [Pt(NH₃)₂Cl₂], an anticancer agent used for treatment of solid tumor is prepared by the reaction of potassium tetrachloroplatinate(II), K₂[PtCl₄], with ammonia :

K₂[PtCl₄] + 2NH₃ à [Pt(NH₃)₂Cl₂] + 2KCl

            Assume that 10.0 g K₂[PtCl₄] and 10.0 g of NH₃  are allowed to react.

d.      Which reactant is limiting and which is excess?

e.       How many grams of the excess reactant are consumed and how many grams remain?

f.       How many grams of cisplatin are formed?

(K=39.1g/mol, Pt=195.1g/mol, Cl=35.5g/mol, N= 14 g/mol, H= 1 g/mol)

4.      Thiophene is a compound that composed from C, H and S elements. 7.96 mg thiophene footage is burned in oxygen produces 16.65 mg CO₂. Another footage of thiophene is reacted to convert sulfur into barium sulfate. if 4.31 mg thiophene produce 11.96 mg  barium sulfate, what is the empirical formula  of thiophene? if the relative molecular mass of thiophene is known 84 g/mol, determine the molecular formula of thiophene?