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Chemistry for HESI

QuestionAnswer
Odor is an example of which physical property of substance? Physical properties of substance are those that can be observed without changing that chemical's composition
Which type of matter has molecules that can't move within the substance and breaks evenly across a plane due to the symmetry of its molecular arrangement? Crystalline solids have atoms or molecules that are arranged symmetrically, making all of the bonds of even strength
What type of reactions involve breaking and re-forming of bonds between atoms? Chemical reactions are processes that involve the changing of one set of substances to a different set of substances.
When is it helpful to use scientific notation to represent numbers? When the number is very large or very small. Scientific notation is the system that represents small numbers behind a decimal point and large numbers without having multiple zeros
Which of the following units is 10-fold greater than a centimeter? Decimeter. The metric system uses a base of 10 between its unit of measure. Ten fold greater than that would be 1/10 of the base which is a decimeter
At what temperature does water boil? 100C which is equivalent to 212F
In which part of the atom is 99% of its mass found? Nucleus
What is different between the isotopes of an atom? The number of neutrons. The total number of protons and neutrons in an atom is the atom's mass number
How are elements with similar chemical properties sorted on the Periodic Table? By columns, they have elements with similar chemical properties such as appearance and reactivity
Which type of reaction is represented by the following equation: A + B ->C? Combination. The equation represents a combination reaction because 2 reactants are being combined to form a larger product.
How do catalysts work to increase the rate of a reaction? By lowering the activation energy required to drive the reaction forward.
Which is NOT a step in solving a stoichiometry problem? A. Find the balance of total products B. Balance the equation C. Add a reactant to the equation Add a new reactant to the equation. Stoichiometry problems don't add new reactants to an equation
What is the molar mass of a substance? The mass of one mole of the substance
Which of the following is one main type of transfer that occurs in redox reactions? A. Transfer of carbon B. Transfer of hydrogen C. Transfer of nitrogen D. Transfer of sulfur Transfer of hydrogen
Which of the following descriptions characterizes an oxidative agent in a redox reaction? A. When it gains a hydrogen B. When it loses an oxygen C. When it gains one or more electrons D. When it gains a carbon When it gains one or more electrons
What's the sum of the oxidation numbers of all the atoms in a neutral compound? 0. Neutral compounds do not have a charge
What color does litmus paper turn if the solution is a base? Blue
What number on the pH scale indicates a neutral solution? 7
Which of the following compounds is an example of a strong base? A. HCI B. HNO3 C. HBr D. NaOH D. A strong base dissociates completely and forms the anion OH. All bases include a hydroxide group (OH) in their formula
What does the half-life of a substance calculate? The time it takes for the substance to reach the halfway point of its lifespan
Which type of nuclear radioactive decay emits 2 protons and 2 neutrons from its nucleus? Alpha. Alpha nuclear decay involves that atom emitting 2 protons and 2 neutrons from its nucleus
Which of the following is NOT one of the 3 elements that can begin a naturally occurring radioactive decay series? A. Uranium-235 B. Thorium C. Uranium-238 D. Neptumiun Neptunium, an artificially-made element that starts an artificial radioactive decay series
How can radiation help with medical treatments? A short exposure can be targeted at a specific are to knock out harmful cells, such as in cancer.
Palmitoleic acid is a fatty acid that is liquid at room temperature. Which is true? A. Palmitoleic acid is a saturated fat B. Palmitoleic acid contains at least one double bond C. Palmitoleic acid is a steroid D. Palmitoleic acid is hydrophilic Palmitoleic acid contains at least one double bond
Which of the following is an essential amino acid? A. Glutamine B. Alanine C. Leucine D. Asparagine Leucine is an essential amino acid. Amino acids can't be consumed for proper health and function because the body can't synthesize them.
What is a redox reaction? Chemical reactions that involve one species of the reactants being oxidized and another species of the reactants being reduced
What is a reactant? An oxidative agent when it gains electrons or oxygen and when it loses a hydrogen
What is the role of the nuclei of radioactive substances? It emits particles and energy in the process of radioactive decay
Created by: ledsingt
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