AP Chemistry Unit 1 Practice

Front

What is the molecular formula of a hydrocarbon that produces equimolar quantities of carbon dioxide and water upon complete combustion?

Back

The molecular formula must have a 2:1 ratio of hydrogen to carbon, such as C4H8.

Front

How many isotopes are present in a mass spectrum?

Back

The number of isotopes can be determined by the number of distinct peaks in the mass spectrum.

Front

How do you calculate the number of neutrons in an isotope?

Back

Number of neutrons = Mass number - Atomic number.

Front

If a supplement contains 53.7% Fe by mass and weighs 3.45 g, how do you find the mass of C4H2Fe3O4 in the supplement?

Back

Mass of C4H2Fe3O4 = (Mass of supplement) * (Percentage of Fe) / (Molar mass of C4H2Fe3O4) * (Molar mass of Fe).

Front

What is the trend in first ionization energy across a period in the periodic table?

Back

First ionization energy generally increases across a period from left to right.

Front

What is complete combustion?

Back

Complete combustion occurs when a hydrocarbon reacts with excess oxygen to produce carbon dioxide and water.

Front

Define isotopes.

Back

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

Front

What is the significance of molar mass in chemistry?

Back

Molar mass is the mass of one mole of a substance, used to convert between grams and moles.

Front

How do you determine the empirical formula from a molecular formula?

Back

Divide the subscripts in the molecular formula by their greatest common divisor.

Front

What is the relationship between atomic number and the number of protons in an atom?

Back

The atomic number of an element is equal to the number of protons in its nucleus.