Stoichiometry Remediation 2

Stoichiometry Remediation 2

1.8

• LIMITING Reactant - Reactant that runs out to ZERO first

• EXCESS Reactant - Reactant that is LEFT OVER and unused because there is no more of limiting reactant to react with it

• both are NOT PRODUCTS!!!

Open Ended

Anna thinks that the red line represents the Excess reactant. Is she correct? Explain your reasoning.

Open Ended

Joselin thinks that $N_2$   represents the Excess reactant. Is she correct? Explain your reasoning.

Open Ended

Which is the limiting reactant in this graph? Explain.

Open Ended

Which is the excess reactant in this graph? Explain.

Open Ended

Which is the product in this graph? Explain.

1.9 Percent Yield

• Calculate it using the formula

• How much you got vs how much you expected

Open Ended

1.9 A chemist uses 1000g of reactants including 400g of Hydrogen gas and 600g of Oxygen gas. He calculated that 950g of water should be produced but only 550g was made in the experiment.

What is the percent yield of water?

Open Ended

If an experiment could have produced 50.0 grams of CO₂ but only produced 32.7 grams, what is the percent yield?

Open Ended

Cu + 2 AgNO₃ → 2 Ag + Cu(NO₃)₂

Cynthia calculated that 169.74 grams of Ag can be produced when 50.0 grams of Cu reacts with AgNO₃. If 150.8 grams of Ag are collected, what is the percent yield?

1.10 PERCENT COMPOSITION

• Find Molar Mass of entire compound

• Divide mass of 1 element by molar mass of ENTIRE compound

Open Ended

What is the percent composition of each element in Al₂(SO₄)₃ ?

1.11 Empirical Formula

• Most simplified ratio of elements in the formula

Calculate Empirical Formula

Example Problem

EMPIRICAL vs MOLECULAR FORMULA

Open Ended

An oxide of chromium is found to have the following % composition: 68.4 % Cr and 31.6 % O. Determine this compound's empirical formula.

Open Ended

The percent composition of a compound was found to be 63.5 % silver, 8.2 % nitrogen, and 28.3 % oxygen. Determine the compound's empirical formula.

1.12 Molecular Formula

Open Ended

A compound has C₁₀H₇O₂ as its empirical formula It has a molecular weight of 318.31 g/mol. What is the molecular formula for this compound?

Open Ended

A compound with an empirical formula of C₂OH₄ and a molar mass of 88 grams per mole. Find the molecular formula of the compound.

Open Ended

A compound with a molar mass of 544.0 g/mol is made up of 26.5 grams Carbon, 2.94 grams Hydrogen, and 70.6 grams Oxygen. What is its empirical and molecular formula?