HESI A2 CHEMISTRY SET QUESTIONS AND ANSWERS 2025
What makes an atom's physical structure? - ✔ A nucleus and
orbits(sometimes known as electron clouds)
What composes the center of the atom? - ✔ Protons and neutrons
What spins in the orbits of an atom? - ✔ Electrons
What are the energy levels of the atom called? - ✔ Shells or orbits
What is the term used to define an atom that is electrically charged? - ✔
Ionic state.
What is a cation? - ✔ An atom with a positive charge
What is anion? - ✔ An atom with a negative charge
What is the structure of the periodic table? - ✔ A series of rows called
periods, and columns called groups.
What can be predicted by the group an element occupies? - ✔ Charge and
the numbers of electrons in its outer shell.
What is the name and properties of group VIII of the periodic table? - ✔
Noble gases.
They tend to remain neutral in most situations, because their outer orbits are
complete.
What is the atomic number? - ✔ The number of protons in the nucleus,
defines an atom of a particular element.
What is the atomic mass? - ✔ The average mass of an element's isotopes.
What are isotopes? - ✔ Different kinds of the same atom that vary in weight.
What is a compound? - ✔ The combination of different elements.
, What do chemical reactions resemble? - ✔ A cooking recipe.
What are the reactants in a chemical reaction? - ✔ The ingredients of a
chemical reaction.
What is the term given to the results of a chemical reaction? - ✔ The
products.
Why must a chemical equation be balanced at the end of a reaction? - ✔
Because the law of conservation of mass indicates that mass cannot be created
nor destroyed in a chemical reaction.
What are equilibrium reactions? - ✔ Chemical reactions that stop before all
the reactants are used to make the products.
What causes equilibrium? - ✔ The state in which reactants are forming
products at the same rate that products are forming reactants.
What are the four basic ways to increase the reaction rate? - ✔ Increase
temperature
Increase the surface area of the reactants
Add a catalyst
Increase the concentration of the reactants.
What does increasing temperature cause in a chemical reaction? - ✔ The
particles have greater kinetic energy, increasing the speed at which they move
around, and the chance of collision between particles.
How does increasing the surface area of the particles in a reaction speed
chemical reactions? - ✔ Gives the Particles more opportunities to come in
contact with each other.
What is a catalyst? - ✔ An agent that accelerates a chemical reaction by
reducing the activation energy or the amount of energy necessary for a
reaction to occur.
What makes an atom's physical structure? - ✔ A nucleus and
orbits(sometimes known as electron clouds)
What composes the center of the atom? - ✔ Protons and neutrons
What spins in the orbits of an atom? - ✔ Electrons
What are the energy levels of the atom called? - ✔ Shells or orbits
What is the term used to define an atom that is electrically charged? - ✔
Ionic state.
What is a cation? - ✔ An atom with a positive charge
What is anion? - ✔ An atom with a negative charge
What is the structure of the periodic table? - ✔ A series of rows called
periods, and columns called groups.
What can be predicted by the group an element occupies? - ✔ Charge and
the numbers of electrons in its outer shell.
What is the name and properties of group VIII of the periodic table? - ✔
Noble gases.
They tend to remain neutral in most situations, because their outer orbits are
complete.
What is the atomic number? - ✔ The number of protons in the nucleus,
defines an atom of a particular element.
What is the atomic mass? - ✔ The average mass of an element's isotopes.
What are isotopes? - ✔ Different kinds of the same atom that vary in weight.
What is a compound? - ✔ The combination of different elements.
, What do chemical reactions resemble? - ✔ A cooking recipe.
What are the reactants in a chemical reaction? - ✔ The ingredients of a
chemical reaction.
What is the term given to the results of a chemical reaction? - ✔ The
products.
Why must a chemical equation be balanced at the end of a reaction? - ✔
Because the law of conservation of mass indicates that mass cannot be created
nor destroyed in a chemical reaction.
What are equilibrium reactions? - ✔ Chemical reactions that stop before all
the reactants are used to make the products.
What causes equilibrium? - ✔ The state in which reactants are forming
products at the same rate that products are forming reactants.
What are the four basic ways to increase the reaction rate? - ✔ Increase
temperature
Increase the surface area of the reactants
Add a catalyst
Increase the concentration of the reactants.
What does increasing temperature cause in a chemical reaction? - ✔ The
particles have greater kinetic energy, increasing the speed at which they move
around, and the chance of collision between particles.
How does increasing the surface area of the particles in a reaction speed
chemical reactions? - ✔ Gives the Particles more opportunities to come in
contact with each other.
What is a catalyst? - ✔ An agent that accelerates a chemical reaction by
reducing the activation energy or the amount of energy necessary for a
reaction to occur.
