Question:

Taking AP Chem but forgot how to answer certain problems please help?

by  |  earlier

0 LIKES UnLike

1)Hydrogen cyanide is produced industrially from the reaction of gaseous ammonia, oxygen, and methane.

2 NH3(g) + 3 O2(g) + 2 CH4(g) 2 HCN(g) + 6 H2O(g)

If 6.00 103 kg each of NH3, O2, and CH4 are reacted, what mass of HCN and of H2O will be produced, assuming 100% yield?

2)Mercury and bromine will react with each other to produce mercury(II) bromide.

Hg(l) + Br2(l) HgBr2(s)What mass of reagent is left unreacted?

What mass of HgBr2 can be produced from the reaction of 2.68 mL mercury (density = 13.6 g/mL) and 2.68 mL bromine (density = 3.10 g/mL)?

3)A student prepared aspirin in a laboratory experiment using the following reaction.

C7H6O3

+ C4H6O3 C9H8O4 + HC2H3O2

salicylic acid acetic anhydride aspirin

The student reacted 2.00 g salicylic acid with 2.67 g acetic anhydride. The yield was 2.00 g aspirin. Calculate the theoretical yield and the percent yield for this experiment.

4)Consider the following unbalanced reaction.

P4(s) +F2(g) PF3(g)

How many grams of F2 are needed to produce 111 g of PF3 if the reaction has a 78.1% yield?

5)Only one isotope of this element occurs in nature. One atom of this isotope has a mass of 9.123 10-23 g. Identify the element and give its atomic mass.

6)The empirical formula of styrene is CH; the molar mass of styrene is 104.14 g/mol. How many H atoms are present in a 8.70 g sample of styrene?

7)A binary compound between an unknown element E and hydrogen contains 91.27% E and 8.73% H by mass. If the formula of the compound is E3H8, calculate the atomic mass of E.

8)A compound contains only carbon, hydrogen, nitrogen, and oxygen. Combustion of 0.157 g of the compound produced 0.213 g CO2 and 0.0310 g H2O. In another experiment, it is found that 0.103 g of the compound produces 0.0230 g NH3. What is the empirical formula of the compound? Hint: Combustion involves reacting with excess O2. Assume that all the carbon ends up in CO2 and all the hydrogen ends up in H2O. Also assume that all the nitrogen ends up in the NH3 in the second experiment. (Type your answer using the format C2H5NO3 for C2H5NO3.)

9)Nitric acid is produced commercially by the Ostwald process, represented by the following equations.

4 NH3(g) + 5 O2(g) 4 NO(g) + 6 H2O(g)

2 NO(g) + O2(g) 2 NO2(g)

3 NO2(g) + H2O(l) 2 HNO3(aq) + NO(g)

What mass in kg of NH3 must be used to produce 8.4 106 kg HNO3 by the Ostwald process, assuming 100% yield in each reaction?

10)A new grill has a mass of 30.0 kg. You put 3.5 kg of charcoal in the grill. You burn all the charcoal and the grill has a mass of 30.0 kg. What is the mass in kg of the gases given off? (assume that the charcoal is pure carbon solid and that it burns completely in oxygen).

11)A student prepared aspirin (C9H8O4) in a laboratory experiment using the following reaction.

C7H6O3 + C4H6O3 C9H8O4 + HC2H3O2

The student reacted 2.50 g salicylic acid (C7H6O3) with 3.33 g acetic anhydride (C4H6O3). The yield was 2.50 g aspirin. Calculate the theoretical yield and the percent yield for this experiment.

Thank You Much

 Tags:

   Report

1 ANSWERS


  1. Moles NH3 = 6000 g / 17 g/mol = 353

    moles O2 = 6000 g / 32 = 187.5

    Moles CH4 = 6000 g / 16 = 375

    ratio = 2 :3 : 2

    O2 is the limiting reactant

    we get 187.5 x 2 / 3  = 125 moles HCN => 125 x 27 g/mol = 3375 g

    and 187.5 x 6 / 3 =375 moles water => 375 x 18 =6750 g

    Mass Hg = 2,68 x 13.6 = 36.4 g

    moles Hg = 36.4 / 200.6 = 0.182

    mass Br2 = 2.68 x 3.10 = 8.31

    Moles Br2 = 8.31 / 159.8 = 0.05200

    Moles Hg in excess = 0.182 - 0.0520 =0.130

    Mass Hg in excess = 0.130 x 200.6 = 26.1 g

    we get 0.0520 moles HgBr2 => 0.0520 x 360.4 = 18.7 g

    I hope this can help you

Question Stats

Latest activity: earlier.
This question has 1 answers.

BECOME A GUIDE

Share your knowledge and help people by answering questions.