HESI CHEMISTRY Q&A

An unknown element is found to contain 45 protons and an atomic mass of 64, what is its atomic number?

45 (atomic number is the same amount of protons)

Which of the following is the atomic mass of an atom containing 31 protons 31 electrons and 37 neutrons?

68 (protons + neutrons = atomic mass)

What is most likely the pH of a solution containing many hydroxide ions (OH-) and few hydrogen ions (H+)?

9

What is the total number of sulfur atoms represented in 3Ca(S04)3?

9

Which pH would be the most basic?

9

What is the charge on sodium in the compound NaCl ?

+1

What is the charge of an alpha particle?

+2

Which of the following correctly describes the oxidation state of the sulfur atom in sulfuric acid?

+6

A scientist discovers an atom of sodium in its natural state. The scientist knows that the oxidation number of this atom is most likely:

0

A concentration of 120.9132 g of MgO in 3 L of solution will be what molality? (The atomic weight are: Magnesium: 24.305 g/mol, Oxygen: 15.9994 g/mol)

1.0 mol MgO

A substance with a pH of 3 is how many times more acidic than a substance with a pH of 5?

100

Glycolysis results in a net gain of how many ATP molecules?

2

An unknown element has a mass number of 33 and an atomic number of 12. How many neutrons does the element contain?

21

The chemical 4[NH4Fe(SO4)2⋅12H] contains how many more hydrogen atoms than oxygen atoms?

32 hydrogen atoms

A normal human body temperature in Celsius is:

37 degrees Celsius

How many glucose molecules are required to balance the following reaction: _C6H12O6 + 24O2 → 24CO2 + 24H2O + Energy

4

Given enough time, unstable nuclei will:

decay into a stable form

Which of these is not a property of water?

density of liquid form is less than solid form

The process by which silver nitrate and potassium chloride yields silver chloride and potassium nitrate is an example of which type of chemical reaction?

double displacement

Polarity is based on the difference in:

electronegativity values for the elements involved in the bond.

A chemical bond is determined primarily by what particles?

electrons

What is the name for substances that cannot be broken down into simpler types of matter?

elements

Reactions that absorb heat are called ____.

endothermic

A student is observing a chemical reaction occurring with visible bubbling. The bubbling eventually stops. The student can see that some of the original reactants are still intact inside the beaker, so he knows that not all the reactant has been used up. Therefore, the student knows he is now observing:

equillibrium

Which of the following is *not* an allotrope of carbon?

fluorine

Which of the following saccharides are commonly associated with the sweet taste of fruit?

fructose

Nora makes soup by adding some spices to a pot of boiling water and stirring the spices until completely dissolved. Next, she adds several chopped vegetables. What is the solute in her mixture?

spices

Viscosity increases when ____.

temperature decreases

Which of the following statements is not true of most metals?

they are gasses at room temperature

DNA and RNA contain many of the same nitrogen-containing bases. Which base is only found in RNA?

uracil

Which of the following is exchanged between two or more atoms that undergo ionic bonding?

valence electrons

Which of these is a water-soluble vitamin?

vitamin C & B

Which of the following is the correct description of stoichiometry?

Stoichiometry is the calculation of relative quantities of reactants and products in chemical reactions.

What are isotopes?

Isotopes are the same element, with the same number of protons and electrons, but a different number of neutrons. Because there are different numbers of neutrons, the atomic masses of the elements also differ.

The pH scale ranges from 0 to 14, where 0 is more _____ and 14 is more ______.

acidic, basic

A chemical drain cleaner that contains sodium hydroxide would be:

alkaline

List these common radiation types from weakest to strongest in terms of penetrability: Alpha, Beta, and Gamma radiation.

alpha, beta, gamma

The rate of a chemical reaction depends on all of the following except:

amount of mass lost

In an ionic bond, a positively charged ion is attracted to what type of ion?

anion

DNA features two sugar-phosphate chains that run in opposite directions, with one up and one down. This characteristic is known as:

anti-parallel

When atoms of one element are combined with atoms of another element, the result is a(n) _________ of a compound.

molecule

Simple carbohydrates composed of a single ring are also called ____.

monosaccharides

What is the metric prefix meaning one billionth?

nano

What is the name of NO2?

nitrogen dioxide

What characteristic of an element determines its specific isotope?

number of neutrons

What is the most abundant element in Earth's crust?

oxygen

Elements in the same ROW, going from left to right in the periodic table are called

periods (from left to right)

Positively charged particles in an atom are called ____.

protons

Which of the following subatomic particles are found inside of an atom's nucleus?

protons, neutrons

What are the two types of measurement important in science?

quantitative and qualitative

A catalyst increases which of these in a chemical reaction?

rate

If gas A has 4 times the molar mass of gas B, you would expect it to diffuse through a plug..

at half the rate of gas B

In the formula C12H22O11, the 12 following the carbon represents 12 ____ of carbon.

atoms

A solution that contains the maximum amount of dissolved solute is said to be ____.

saturated

The elements that form a staircase pattern on the right side of the periodic table can be classified as..

semimetals

Fe + CuSO4 → FeSO4 + Cu is an example of what type of reaction?

single replacement

High density matter, which is little affected by pressure and holds its shape, is classified as ____.

solid

Which of the answer choices provided best defines the following statement: For a given mass and constant temperature, an inverse relationship exists between the volume and pressure of a gas?

Boyle's Law

The breakdown of ____ provides the energy needed for chemical reactions in the body.

ATP

DNA is made up of which of the following nucleotides?

Adenine, Guanine, Cytosine, and Thymine

What is the basic structure of an amino acid?

An amine group, a carboxyl group, and a functional R-group

Which of the following statements about atoms is false?

Atoms are most stable when their outer electron shell (valence shell) is incomplete.

Fluorine, oxygen, and nitrogen would each form what type of bond with a hydrogen atom?

Fluorine, oxygen, and nitrogen are likely to form hydrogen bonds because they are each lacking electrons in their outer shell. Covalent bonds would form because hydrogen readily accepts single covalent bonds (sharing of its electron) and polar because hydrogen has a very low electronegativity compared to most elements.

The addition of a catalyst to a chemical reaction will have what effect?

Increase the rate at which the reaction takes place

Which of the following is true?

Mass is the quantity of matter an object has

What is the typical way a solid would turn to a liquid and then to a gas?

Melting then vaporization

Which of these is a polar molecule?

NH3

Which of the following is an example of a ionic bond?

NaCl

Between which two molecules is a phosphodiesterase bond?

PO4 and another molecule

You would expect an amino acid to contain which 2 functional groups?

R-NH2 and R-COOH

What is freezing point?

The point at which a liquid changes to a solid

What is the purpose of scientific notation?

The purpose is to handle both smaller and bigger numbers more easily.

BF3 is also known as ____.

boron trifluoride

In a complete combustion reaction involving adequate amounts of oxygen and a compound containing carbon and hydrogen, the products are always?

carbon dioxide and water

What does -COOH symbolize?

carboxyl group

The change in state from a gas to liquid is called ____.

condensation

Which is a property of an ionic compound?

crystalline shape

Elements that are in the same column of the periodic table are in the same:

group (or family that share similar chemical behavior)

The vertical columns of the periodic table are called ____.

groups

Bleaches, disinfectants, and salts often contain elements from which nonmetal group?

halogens

What is the most abundant element in the universe?

hydrogen

The strongest bond between liquid water molecules is called ____.

hydrogen bonds

A particle with a negative or positive charge is referred to as ____.

ion

An atom with an electrical charge is called a(n):

ion

Which of these is not a component of lipids?

iron

Which of these describes the properties of a real gas?

it possesses mass

Which of the following creates a cramping sensation during intense exercise?

lactate

Which of the following is not a state of matter?

lattice

Foods such as oils, milk, and butter contain high amounts of:

lipids

In a redox reaction, the element that is oxidized _____ an electron and the element that is reduced _____ an electron.

loses, gains

Which is not a property of metals?

low density

Which of the following cannot be found on the periodic table?

magnesium oxide

Which of these elements is liquid at room temperature?

mercury