Unit 3 Conceptual Chemistry Assessment

Front

What is the empirical formula for a compound with the molecular formula C4H6?

Back

C2H3

Front

How do you balance the chemical equation Fe + O2 -> Fe2O3?

Back

4Fe + 3O2 -> 2Fe2O3

Front

What is the definition of an empirical formula?

Back

A formula with the lowest whole number ratio of elements in a compound.

Front

What does a molecular formula indicate about a compound?

Back

The total number of atoms of each element in the compound.

Front

How do you calculate the concentration of a solution in parts per million (ppm)?

Back

Concentration (ppm) = (mass of solute in grams / mass of solution in grams) x 1,000,000.

Front

What is the molecular formula for a compound with an empirical formula of CH and a molecular weight of 78 g/mol?

Back

C6H6 (Benzene)

Front

What is the difference between empirical and molecular formulas?

Back

Empirical formula shows the simplest ratio of elements, while molecular formula shows the actual number of atoms in a molecule.

Front

What is the balanced equation for the combustion of propane (C3H8)?

Back

C3H8 + 5O2 -> 3CO2 + 4H2O

Front

What is the significance of balancing chemical equations?

Back

It ensures the law of conservation of mass is followed, meaning atoms are neither created nor destroyed.

Front

What is the formula for calculating molarity (M) of a solution?

Back

Molarity (M) = moles of solute / liters of solution.