Chemistry Fall Semester Review 2024

Front

What is an empirical formula?

Back

An empirical formula represents the simplest whole-number ratio of atoms of each element in a compound.

Front

How do you convert grams of an element to atoms?

Back

To convert grams to atoms, divide the mass in grams by the molar mass of the element to find moles, then multiply by Avogadro's number (6.022 x 10^23) to find the number of atoms.

Front

Who discovered the electron using the cathode ray tube experiment?

Back

J.J. Thomson discovered the electron using the cathode ray tube experiment.

Front

What is the molar mass of silicon (Si)?

Back

The molar mass of silicon is approximately 28.09 g/mol.

Front

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

Back

The average atomic mass is calculated using the weighted average method, multiplying the mass of each isotope by its relative abundance (as a fraction) and summing the results.

Front

What is the formula to convert grams to moles?

Back

Moles = Mass (g) / Molar Mass (g/mol).

Front

What is the significance of Avogadro's number?

Back

Avogadro's number (6.022 x 10^23) is the number of atoms, ions, or molecules in one mole of a substance.

Front

What is the plum pudding model of the atom?

Back

The plum pudding model, proposed by J.J. Thomson, suggests that the atom is a sphere of positive charge with negatively charged electrons embedded within it.

Front

What is the definition of isotopes?

Back

Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons.

Front

How do you find the number of moles from grams of a substance?

Back

To find moles from grams, divide the mass of the substance by its molar mass.