Unit 3 Chemistry Assessment

Front

What is the balanced equation for the reaction of iron and oxygen to form iron(III) oxide?

Back

4Fe + 3O₂ → 2Fe₂O₃

Front

How many moles of iron can be produced from 6 moles of hydrogen in the reaction: Fe₂O₃ + 3H₂ → 2Fe + 3H₂O?

Back

4 moles Fe

Front

What is the molarity of a solution made by dissolving 2 moles of CaCO₃ in 1.22 L of solution?

Back

1.64 M

Front

Define empirical formula.

Back

A formula that shows the simplest whole number ratio of elements in a compound.

Front

In the reaction 2H₂ + O₂ → 2H₂O, how many moles of oxygen are consumed when 8 moles of hydrogen are used?

Back

4 moles O₂

Front

What is the definition of molarity?

Back

Molarity is the number of moles of solute per liter of solution.

Front

What is the difference between molecular formula and empirical formula?

Back

Molecular formula shows the actual number of atoms of each element in a molecule, while empirical formula shows the simplest ratio of elements.

Front

How do you calculate the number of moles from mass?

Back

Number of moles = mass (g) / molar mass (g/mol).

Front

What is the significance of balancing chemical equations?

Back

Balancing chemical equations ensures the law of conservation of mass is followed, meaning the number of atoms of each element is the same on both sides.

Front

What is the molar mass of water (H₂O)?

Back

18.02 g/mol