Chem: Lab Report: Mole And Mass Relationships 5u1z1l

LAB REPORT MOLE AND MASS RELATIONSHIPS

PURPOSE Compare the experimental mass of a product of a chemical reaction with the mass predicted for that product by calculation.

DATA & CALCULATIONS DATA COLLECTED Variable evaporating dish + watch glass evaporating dish + watch glass + evaporating dish + watch glass +

Value 60.54 g 63.03 g 62.29 g

Table 1. The measurements taken for the Lab.

CALCULATIONS MASS OF THE

MASS OF THE

Variable mass of the mass of the

REACTANT

PRODUCT

product product

Table 2. Contains the calculations for the Lab.

Jonathan Sterling

Value 2.49 g 1.75 g

Jonathan Sterling

CONCLUSIONS AND QUESTIONS 1.

2.

According to the balanced equation for the reaction used in this experiment, what is the ratio of moles of reacted to moles of produced? The equation is . Because there are no coefficients, the ratio would have to be 1:1. How many moles of are reacted in this experiment? How many moles of is produced? What is the ratio of moles reacted to moles of produced?

Therefore, about

3.

were reacted.

Therefore, about were reacted. Thus, the ratio of moles reacted to moles produced is 1:1. Using the balanced equation, calculate the mass of you would expect to get when is reacted with . How does this value compare with the mass attained experimentally?

This theoretical value is very close to the experimental value, but the experimental value would probably have been different had the sodium hydrogen carbonate been measured to exactly (it was ). To test this, one can simply change the equation a bit to get the following:

4.

5.

2

In the end, the experimental and theoretical values were not identical, but very, very close. If the masses of all but one of the substances that take part in a chemical reaction are known, explain why it is possible to determine the unknown mass by subtraction? The Law of Conservation of Mass states that no matter can be created or destroyed; therefore, in a reaction, no matter is lost. If one has all but one mass value, it would logically follow that one has all the masses of either the reactants or the products. All one must do is add all of masses the products or reactants (whichever group is completely known) together and then subtract the masses of the known reactants or products (whichever group is not completely known). The resulting answer is the unknown mass. In the chemical reaction , if is decomposed: a. how many grams of are produced?

Jonathan Sterling

b. how many grams of

6.

are produced?

In the reaction , if react: a. how many grams of ammonia are produced?

b. how many grams of nitrogen react?

3