Chemistry Midterm Exam 2024

Front

What is the mole ratio of aluminum to oxygen in the reaction 2Al₂O₃ → 4Al + 3O₂?

Back

4:3

Front

What are the coefficients that correctly balance the equation NH₄NO₂(s) → N₂(g) + H₂O(l)?

Back

1 1 2

Front

What are ions?

Back

Atoms with a positive or negative charge.

Front

What is an example of a chemical change?

Back

Iron rusting.

Front

How do you calculate the average atomic mass of an element with multiple isotopes?

Back

Multiply the relative mass of each isotope by its abundance, sum the results, and divide by 100.

Front

What is the atomic mass of Uranium (#92)?

Back

238.03 amu.

Front

Define isotopes.

Back

Atoms of the same element with different numbers of neutrons.

Front

What is the difference between a physical change and a chemical change?

Back

A physical change alters the form of a substance without changing its identity, while a chemical change results in the formation of new substances.

Front

What is the law of conservation of mass?

Back

In a chemical reaction, mass is neither created nor destroyed.

Front

What is a balanced chemical equation?

Back

An equation where the number of atoms for each element is the same on both sides.