Question #f572e
2 Answers
Always start by writing a balanced chemical equation for the reaction that you have to work with.
In your case, you're dealing with a single replacement reaction in which zinc, the more reactive metal, displaces copper to form zinc sulfate and copper metal
Notice that you have
So, determine how many moles of zinc you have by using its molar mass
Since copper sulfate is in excess, zinc will be your limiting reagent, i.e. it will be completely consumed by the reaction.
If 0.0306 moles of zinc are consumed, and you have a
Now use copper's molar mass to determine how many grams you'd produce
Since you only gave one sig fig for the 2-g mass of zinc, the answer will be
Check out these links, there are many more solved problems you could use as examples
http://socratic.org/chemistry/stoichiometry/limiting-reagent
http://socratic.org/chemistry/stoichiometry/percent-yield
http://socratic.org/chemistry/stoichiometry/equation-stoichiometry
Here are the basic steps to solve a theoretical yield problem.
- Write the balanced equation for the reaction between
#"Zn"# and#"CuSO"_4# . - Use the molar mass of
#"Zn"# to convert grams of#"Zn"# to moles of#"Zn"# . - Use the molar ratio from the balanced equation to convert moles of
#"Zn"# to moles of#"Cu"# . - Use the molar mass of
#"Cu"# to convert moles of#"Cu"# to grams of#"Cu"# .
In summary, the conversions are
To 1 significant figure, you should get