Stoichiometry Problems

1.      How many atoms are there in one mole of oxygen gas?
2.      What is the mass of
a)      238 moles of iron metal
b)      0.0035 moles of Na2HPO4
c)      7.70 x 10−6 moles of helium gas
d)      1.206 x 1024 atoms of N2 gas
 3.      How many moles are contained in the following substances
a)      1.50 g of silver metal
b)      a 127 g spool of copper wire
c)      4.00 g sample of argon gas
4.      If potassium chlorate is heated gently, the crystals will melt.  Further heating will decompose it to give oxygen gas and potassium chloride.
a)      Write the formula for the reactants and products.
b)      Write the balanced equation for the decomposition of potassium chlorate.
c)      How many grams of potassium chloride are produced when 3.5 moles of potassium chlorate are decomposed?
d)      How many moles of potassium chlorate are needed to give 1.5 moles of oxygen gas.
e)      How many liters of oxygen gas at STP will be produced by decomposing 122.6 g of potassium chlorate?
5.      Xenon is a noble gas. One of the first compounds made from xenon was xenon tetrafluoride, XeF4. When 10.0 g of xenon gas react completely  with fluorine to give xenon tetrafluoide, 39.8 kJ of energy are released. The equation for the reaction is:
Xe(g)  +  2F2(g)  →  XeF4(s)
Using this information calculate how much energy is released when 1 mole of xenon gas reacts.
6a) How would you go about preparing 150 mL of 1.5 M barium nitrate solution from solid barium nitrate, Ba(NO3)2?
 b) Determine the molarity of a solution containing 0.15 g of KOH in 25 mL of solution.
6.      Solutions of FeBr3 and KOH are mixed and a reddish solid, called a precipitate, Fe(OH)3, is formed.
a)      Write the molecular equation for the above reaction. It must be balanced.
b)      Write the total ionic equation for the reaction.
c)      Write the net ionic equation for the reaction.