Consider 10 g of the compound formic acid. It has a molecular formula CH2O2. Answer the following:

a) How many moles of formic acid? Answer 0.217 mole

b) How many moles of carbon? Answer 0.217 mole

c) how many moles of hydrogen? Answer 0.434 mole

d) How many moles of oxygen ? Answer 0.434 mole

e) How many carbon atoms ? Answer 1.361x10^+23 atoms

f) How many hydrogen atoms ? Answer 2.61x10^+23 atoms

g) How many oxygen atoms ? Answer 2.61x10^+23 atoms

h) How many total moles of atoms ? Answer 1.085 mole

i) how many total atoms ? Answer 6.534x10^+23 atoms

What is the mass of 2.500x10^+25 molecules of methanol (CH4O) ?

Answer 1,328 g

What is the molecular weight of Aspirin (acetylsalysylic acid: C9H8O4).

Answer 180 g/mol

Lactic acid contains C, H and O atoms. The mass percentage of these atoms is C: 40%, H: 6.7%, 53.3%. The molecular weight of lactic acid is 90 g/mol.

a) What is the emprical formula of lactic acid? Answer CH2O

 

b) What is the molecular formula of lactic acid? Answer C3H6O3

Lead metal is obtained from the mineral lead sulfide through the following reaction:

a) If 100 g of PbS is reacted with excess C and O2 what mass of lead metal will be obtained? Answer 86.6 g Pb

 

b) Suppose 100 g of PbS is reacted with 4g of C and excess O2.

 

i) What is the limiting reactant? Answer carbon

 

ii) What mass of lead metal will be obtained? Answer 69g of Pb

 

c) What mass of oxygen is needed to produce 500 g of lead metal? Answer 116g of O2

Hydrogen and oxygen gas react to form water:

This reaction is exothermic and releases -285.8 kJ of heat. How much heat will be released if10 g of H2(g) is reacted with excess oxygen? Answer -1,429 kJ