Stoichimetry f a Precipitation Reaction

 

Stoichiometry of a Precipitation Reaction

 

 

Questions

 

A.    From your balanced equation what is the theoretical yield of your product?
I got

 

B.    According to your data table, what is the actual yield of the product?
64.6g

 

C.    A perfect percent yield would be 100%. Based on your results, comment on your degree of accuracy and suggest possible sources of error.

Possible sources of error could be occurring in the weigh boat.

 

D.    How could these errors be reduced in the future?

Use the water to make the weigh boat clean and thereby getting all into the mixture.

Physical & Chemical Properties

Substance: Mg

Color: red-brown

Odor: metallic

Effect of Heat: crunched

Litmus test: solid

Substance: Cu

Color: reddish brown

Odor: metallic

Effect of Heat: holes developed

Litmus test: purple

Substance: Zn

Color: silvery

Odor: metallic

Effect of Heat: develops holes and steams

Litmus test: purple

Substance: NaCl

Color: opaque white

Odor: salty

QUESTIONS:

A - Did you observer any chemical changes in this experiment?
yes

B - What evidence did you use to decide that something was a chemical change?
element and reactions

 

C - Give at least two examples of chemical changes you observed.
steaming, formations

D - Classify the following properties of sodium metal as physical or chemical:

            Silver metallic color – physical

            Turns gray in air – chemical

            Melts at 98^oC - physical

            Reacts explosively with chlorine - chemical

E - Classify the following changes as physical or chemical:

            Water freezes at O^oC - physical

            Baking soda when combined with vinegar produces bubbles:- chemical

            Mothballs gradually disappear at room temperature – physical

            Ice cubes in a freezer get smaller with time – physical

            Baking soda loses mass as it is heated – chemical

            Tarnishing of silver – physical

F - How would you show that dissolving table salt is a physical change?

            Dehydrate the solution