HESI A2 (NURSING ADMISSION TEST) 2023 CHEMISTRY
1 A mystery element has 6protons,6 electrons
and 6neutrons.What is its atomic number?
a. 6
b. 12
c. 18
d. Notenoughinformation
The correct answer is A. An atom can always be identified based on the
number of protons which willalways be the same for atoms of the same
element. The atomic number is always equal to the number ofprotons.
2. A mystery element has 13 protons,13 electronsand14neutrons.What element is
it?
a. Fe
b. Zr
c. Al
d. Notenoughinformation
The correct answer is C. Atoms can always be identified with the number
of protons. Since this atom has13 protons, the atomic number is 13,which is
aluminum.
3. What are buffers?
a. Proteins
b. SolutionsthatresistchangesinpH
c. Catalystsinareaction
d. Inhibitorsinareaction
The correct answer is B. Buffers resist change in pH and are key to
maintaining stable H+ion concentrations.
4. What does carbonic acid do within the human body?
a. Digestsfood
b. Killsviruses
c. MaintainspHofblood
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The correct answer is C. Carbonic acid is a buffer that maintains the pH
of human blood. Other acids are present in the stomach in order to digest
food.
Use the following chemical reaction to answer the following questions:
5. What are the reactants?
a. CH4and O2
b. CO2and H2O
The correct answer is A. There actants are always on the left side of are action
and are the atoms or molecules present at the start of a reaction.
6. What are the products?
a. CH4and O2
b. CO2and H2O
c. Both
d. Noneoftheabove
The correct answer is B. Products are made by reactions and are always on the
right side of the arrow.
7. How many hydrogen atoms are present in the reactants?
a. 2
b. 4
c. 1
d. Noneoftheabove
The correct answer isB.The subscript 4 after the H symbol indicates that there
are 4 atoms of hydrogen in CH4.
8. How many oxygen atoms are in2O2?
a. 2
b. 4
c. 1
d. 0
The correct answer is B. The normal sized 2 is called a coefficient. It
means that there are two molecules of whatever comes after it, in this case
there are 2 molecules of O 2. O2 has 2 atoms of oxygen and the coefficient
of 2 means that there would be 4 total oxygen atoms. Coefficients are similar
to distributing in algebra. All subscript numbers involved in the compound
are multiplied by the coefficientamount.
9. How many water molecules are present in the products?
a. 2
b. 4
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c. 1
d. 0
The correct answer is A. The coefficient of 2 before the water molecule
indicates that there are 2 of thatmolecule.
10. Which of the following is most true?
a. 2H2Ohas2hydrogenatomstotal
b. 2H2Oistwowater molecules
c. H2O2istwowatermolecules
d. Noneoftheabove
The correct answer is B. The coefficient of 2 means that there are two
water molecules. In answer A,there would be 4 hydrogen atoms since the
coefficient would be multiplied by the subscript. In answer C,there
aretwohydrogenatomsandtwooxygen atoms.
11. Which of the following is most dense?
a. Ablockofgold thatis 12gand 4.6cm3
b. Acubethat is6gand0.91cm3
c. Ablockthatis143gand 24.3cm3
The correct answer is B. In order to solve this question, one must find the
density of each option andcompare them to find the highest density, which
would be the densest. Answer A is 2.61 g/cm 3, solved
by12g/4.6cm3.AnswerBis6.59g/cm3,solvedby6g/0.91cm3.AnswerCis5.88g/cm3,
solvedby143g/24.3cm3.
12. Solids will always sink in liquids.
a. True,asolidishardandliquidsarenot
b. True,solidsareheavierthanliquids
c. False,solidshaveasmoothsurfacesotheywillfloat
d. False,itdependson thedensityofthesolidandliquid
The correct answer
isD.Substancesdifferentiate,sinkorfloatbasedontheirdensities.Ifasolidisdenser
than the liquid, itwillsink.If the solid islessdense thanthe liquid, itwillfloat.
13. Which of the following has the most molecular interactions?
a. Solid
b. Liquid
c. Gas
d. Noneoftheabove
The correct answer
isA.Solidsarerigidandtheatomsaretightlypackedtogether.Thismeansthatthere
arethemostpossiblemolecularinteractions.
14. Whichofthefollowinghasthemostmolecularmotions?