AC-HPAT Chemistry Verified Exam Questions and Answers Latest
update 2026/2027
Question:
double-displacement reaction
Answer:
A double displacement reaction, also known as a double replacement reaction or metathesis, is a type
of chemical reaction where two compounds react, and the positive ions (cation) and the negative ions
(anion) of the two reactants switch places, forming two new compounds or products
Question:
Precipitate
Answer:
precipitate is an insoluble solid that emerges from a liquid solution. The emergence of the insoluble
solid from solution is called precipitation. Often the precipitate emerges as a suspension. Precipitates
can form when two soluble salts react in solution to form one or more insoluble products.
Question:
Energy Levels
Answer:
Energy levels (also called electron shells) are fixed distances from the nucleus of an atom where
electrons may be found. As you go farther from the nucleus, electrons at higher energy levels have
more energy. Electrons in the outermost energy level of an atom are called valence electrons
Question:
Marquis Test
Answer:
The Marquis Test is commonly used for Ecstasy testing as MDMA turns the precipitate purple black.
Cobalt thiocyanate is used to test for cocaine. The Cobalt is mixed with the questionable substance,
then drowned in hydrochloric acid, doused in chloroform, and shaken.
Question:
What is the relation between an atomic number and a mass number?
Answer:
Atomic number is actually the number of protons in an atom while mass number is the number of
nucleons i. e, number of protons plus the number of neutrons.
, Question:
Isotopes
Answer:
Isotopes refer to the nuclides of a certain element that have different numbers of neutrons, or in other
words, atomic nuclei that have the same number of protons but different numbers of neutrons. A
radioisotope is an isotope that is unstable and therefore undergoes radioactive decay or will at some
point.
Question:
Chemical Synthesis
Answer:
Chemical synthesis, the construction of complex chemical compounds from simpler ones. It is the
process by which many substances important to daily life are obtained. It is applied to all types of
chemical compounds, but most syntheses are of organic molecules.
Question:
Decomposition
Answer:
A decomposition reaction is a type of chemical reaction in which a single compound breaks down into
two or more elements or new compounds. These reactions often involve an energy source such as
heat, light, or electricity that breaks apart the bonds of compounds
Question:
single-displacement reaction
Answer:
A single-displacement reaction, also known as a single-replacement reaction, is a type of chemical
reaction where an element reacts with a compound and takes the place of another element in that
compound. This type of reaction is typically pictured like this: Here, A replaces B in the compound
BC
Question:
Flame test
Answer:
flame test is an analytical procedure used in chemistry to detect the presence of certain elements,
primarily metal ions, based on each element's characteristic emission spectrum. The color of flames in
general also depends on temperature; see flame color.
update 2026/2027
Question:
double-displacement reaction
Answer:
A double displacement reaction, also known as a double replacement reaction or metathesis, is a type
of chemical reaction where two compounds react, and the positive ions (cation) and the negative ions
(anion) of the two reactants switch places, forming two new compounds or products
Question:
Precipitate
Answer:
precipitate is an insoluble solid that emerges from a liquid solution. The emergence of the insoluble
solid from solution is called precipitation. Often the precipitate emerges as a suspension. Precipitates
can form when two soluble salts react in solution to form one or more insoluble products.
Question:
Energy Levels
Answer:
Energy levels (also called electron shells) are fixed distances from the nucleus of an atom where
electrons may be found. As you go farther from the nucleus, electrons at higher energy levels have
more energy. Electrons in the outermost energy level of an atom are called valence electrons
Question:
Marquis Test
Answer:
The Marquis Test is commonly used for Ecstasy testing as MDMA turns the precipitate purple black.
Cobalt thiocyanate is used to test for cocaine. The Cobalt is mixed with the questionable substance,
then drowned in hydrochloric acid, doused in chloroform, and shaken.
Question:
What is the relation between an atomic number and a mass number?
Answer:
Atomic number is actually the number of protons in an atom while mass number is the number of
nucleons i. e, number of protons plus the number of neutrons.
, Question:
Isotopes
Answer:
Isotopes refer to the nuclides of a certain element that have different numbers of neutrons, or in other
words, atomic nuclei that have the same number of protons but different numbers of neutrons. A
radioisotope is an isotope that is unstable and therefore undergoes radioactive decay or will at some
point.
Question:
Chemical Synthesis
Answer:
Chemical synthesis, the construction of complex chemical compounds from simpler ones. It is the
process by which many substances important to daily life are obtained. It is applied to all types of
chemical compounds, but most syntheses are of organic molecules.
Question:
Decomposition
Answer:
A decomposition reaction is a type of chemical reaction in which a single compound breaks down into
two or more elements or new compounds. These reactions often involve an energy source such as
heat, light, or electricity that breaks apart the bonds of compounds
Question:
single-displacement reaction
Answer:
A single-displacement reaction, also known as a single-replacement reaction, is a type of chemical
reaction where an element reacts with a compound and takes the place of another element in that
compound. This type of reaction is typically pictured like this: Here, A replaces B in the compound
BC
Question:
Flame test
Answer:
flame test is an analytical procedure used in chemistry to detect the presence of certain elements,
primarily metal ions, based on each element's characteristic emission spectrum. The color of flames in
general also depends on temperature; see flame color.
