16 free HESI A2 questions from our 150-question bank, grouped by content domain. Each answer explains why the right option is right — and why every wrong option is wrong.
A patient weighs 132 lb. The order is 2.5 mg/kg. The medication is supplied as 50 mg/mL. How many milliliters should be given?
Answer: 3 mL
Weight-based dose: lb → kg, multiply by mg/kg, then divide by the concentration. A common trap is using pounds ( mL), which more than doubles the dose.
A child weighs 44 lb. The prescribed dose is 15 mg/kg/day, given in equal doses every 8 hours. How many milligrams should the child receive in each dose?
Answer: C
300 mg: This is the total daily dose. Every 8 hours means 3 doses in 24 hours, so it must be divided by 3.
220 mg: This uses the weight in pounds (). The dose is per kilogram, so convert 44 lb to 20 kg first.
100 mg: Correct. kg; mg per day; every 8 hours is 3 doses a day, so mg.
660 mg: This uses pounds instead of kilograms and also skips dividing the daily amount into 3 doses.
For mg/kg/day orders: convert to kg, find the daily total, then divide by the number of doses per day.
Add and write the answer as a mixed number in lowest terms:
Answer: B
: This adds the numerators () and the denominators (). Denominators are never added; the fractions need a common denominator first.
: Correct. With a common denominator of 12, the fractions sum to , which is added to the 3 wholes.
: The fraction sum was reduced to without carrying the extra whole 1 into the whole-number part.
: This multiplies the fraction parts () instead of adding them.
Add whole numbers and fractions separately, using a common denominator for the fractions; carry any improper fraction into the whole number.
Why does the author most likely recommend that night workers wear sunglasses on the drive home?
Answer: D
To boost alertness so that tired workers stay awake while driving: Contradicted: the passage says bright morning light signals the day has begun, so blocking it is meant to keep the body ready for sleep, not to make the driver more alert.
To raise melatonin levels during the work shift: Distortion: the shift is over by the drive home, and the passage links melatonin to darkness, not to sunglasses.
To hide signs of tiredness from coworkers: Not supported: nothing in the passage concerns appearance.
To keep morning light from signaling that the day has begun: Correct. Paragraph 2 says "bright morning light tells a small region of the brain that the day has begun"; blocking it on the way home should make daytime sleep easier.
Connect a recommendation in one paragraph to the explanation in another; here the advice in paragraph 4 depends on how light works in paragraph 2.
What is the central idea of "The Eight-Glass Question"?
1Almost everyone has heard the rule that a person should drink eight glasses of water a day. The advice is repeated on posters, in fitness magazines and by well-meaning relatives. It is easy to remember, which may explain its staying power. What is harder to find is solid evidence that the number eight applies to everyone.
2The body's need for water is real and constant. Water helps regulate body temperature, carries nutrients to cells, cushions joints and allows the kidneys to flush waste from the blood. We lose water all day through breathing, sweating and urination. If that water is not replaced, a person can become dehydrated, with symptoms that range from thirst, headache and dark urine to dizziness and confusion in severe cases.
3However, the amount of water a person needs varies widely. A large adult who works outdoors in summer may need far more than a small adult who spends the day in an air-conditioned office. Illness with fever, vomiting or diarrhea raises fluid needs, as do pregnancy and breastfeeding. Just as important, plain water is not the only source. Milk, juice, tea and even coffee count toward daily fluid intake, and foods such as soup, watermelon, cucumbers and oranges contain a great deal of water.
4For most healthy people, thirst is a reasonably reliable guide, and pale yellow urine is a sign that intake is adequate. There are exceptions. Older adults may feel less thirsty even when their bodies need fluid, and people with certain heart or kidney conditions may be told by their health care providers to limit how much they drink. Rather than counting glasses, then, the wiser approach is to pay attention to the body's signals and to follow individual medical advice when it applies.
Answer: A
Fluid needs vary from person to person, so one rule cannot fit all.: Correct. Paragraph 1 questions whether "the number eight applies to everyone," paragraph 3 states that needs "vary widely," and paragraph 4 recommends following the body's signals instead of "counting glasses."
Coffee and tea are just as healthy for the body as plain water.: Not supported: the passage says these drinks "count toward daily fluid intake," not that they are equally healthy.
Dehydration can cause headache, dizziness and confusion.: Too narrow: these symptoms are one detail in paragraph 2.
Most adults drink far less water each day than their bodies really need.: Not supported: the passage never claims that most people are under-hydrated.
Look for the idea the author returns to at the start and the end; here the passage opens by doubting the rule and closes by replacing it.
Which statement best expresses the main idea of the passage about handwashing?
1Few habits are as simple, or as easy to skip, as washing your hands. Most people rinse quickly under the tap and move on, believing that a splash of water is enough. Yet the hands are one of the main routes by which germs travel from one person to another. We touch doorknobs, phones, railings and our own faces many times an hour, and each contact is a chance to pick up or pass along bacteria and viruses.
2Soap works in a way that water alone cannot. Many germs are wrapped in an oily outer layer or cling to the natural oils on the skin. Soap molecules have one end that attracts water and another end that attracts oils. When you lather, these molecules surround the oily material and lift it away from the skin, so that the rinse water can carry it down the drain. For this reason, the scrubbing step matters as much as the soap itself. Health agencies generally advise scrubbing for at least twenty seconds, covering the backs of the hands, the spaces between the fingers and the skin under the nails.
3Alcohol-based hand sanitizers are a useful substitute when a sink is not nearby. They kill many kinds of germs quickly, and in hospitals they are often mounted at the door of every patient room. However, sanitizers work less well when hands are visibly dirty or greasy, and they do not remove some germs as well as soap and water do. They should be seen as a backup, not a replacement.
4In health care settings, hand hygiene is treated as a basic safety practice, and many hospitals track how often staff clean their hands before and after patient contact. Outside the hospital, the stakes are lower but still real. Washing before eating, after using the restroom and after caring for someone who is sick can reduce the spread of colds and stomach illnesses through a household. Handwashing is one of the best bargains in public health: it costs almost nothing and takes less than half a minute.
Answer: B
Hand sanitizers have replaced soap and water in most hospitals.: Opposite: paragraph 3 says sanitizers "should be seen as a backup, not a replacement."
Good handwashing simply and cheaply limits the spread of germs.: Correct. Paragraph 1 names hands as a main route for germs, paragraphs 2–3 explain how proper washing removes them, and paragraph 4 calls it "one of the best bargains in public health." Every paragraph supports this idea.
Germs are carried mainly on doorknobs, phones and stair railings.: Not supported and too narrow: these objects are examples of things hands touch (paragraph 1); the passage never says they are the main carriers of germs.
Soap molecules attract water at one end and oils at the other.: Too narrow: this is one supporting detail from paragraph 2 that explains how soap works.
The main idea is the point that every paragraph supports. A choice that is true but appears in only one paragraph is a detail, not the main idea.
What is the best definition of cursory?
Answer: A
Hasty and superficial: Correct. Cursory means done quickly without attention to detail. Example: "A cursory glance at the chart missed the allergy note."
Rude and offensive: This plays on cursing, a sound-alike; cursory has nothing to do with bad language.
Slow and thorough: This is the opposite of cursory and closer to meticulous.
Final and binding: This describes conclusive or decisive; cursory describes how carefully something is done.
Cursory = quick and shallow; the opposite is thorough.
What is the best definition of febrile?
Answer: C
Weak and easily broken: This describes fragile or friable, a sound-alike trap; febrile has nothing to do with strength.
Confused and disoriented: Confusion can accompany a high fever, but the word for it is disoriented or delirious, not febrile.
Having a fever: Correct. Febrile comes from Latin febris (fever) and means having an elevated body temperature. Example: "The febrile child had a temperature of 102.4 °F."
Free of infection: Free of infection is closer to aseptic. Note that afebrile (without fever) is the opposite of febrile.
Febrile = feverish; afebrile = without fever. Link the root febr- to the word fever.
Which sentence uses apostrophes correctly?
Answer: A
The nurses' lounge is next to the children's play area.: Correct. Nurses is a regular plural ending in s, so the apostrophe goes after the s (nurses'). Children is an irregular plural not ending in s, so it takes 's (children's).
The nurses' lounge is next to the childrens' play area.: Childrens' is wrong: children is already plural, so add 's, not s'.
The nurses lounge is next to the childrens play area.: Both possessives are missing apostrophes, so the words read as plain plurals.
The nurse's lounge is next to the childrens' play area.: Nurse's signals one nurse owns the lounge, and childrens' adds s' to an irregular plural.
Plural ending in s: add an apostrophe (nurses'). Plural not ending in s: add 's (children's, women's, people's).
Which sentence is grammatically correct, with each modifier placed clearly?
Answer: B
Running down the hallway, the IV pole tipped over.: Dangling modifier: the opening phrase describes the IV pole, which cannot run.
Running down the hallway, the nurse bumped the IV pole.: Correct. The introductory phrase Running down the hallway is immediately followed by the person doing the running, the nurse.
The nurse bumped the IV pole running down the hallway.: Misplaced modifier: placed after IV pole, the phrase seems to say the pole was running.
Running down the hallway, the IV pole was bumped by the nurse.: Dangling modifier: the subject right after the comma is the IV pole, so the pole appears to be running.
An introductory modifying phrase must be followed immediately by the noun it describes.
Which word is used incorrectly in the following sentence?
The new medication had no noticeable affect on the patient's blood pressure.
Answer: C
had: Had is the correct past-tense verb for a completed observation.
noticeable: Noticeable is a correctly spelled adjective modifying the noun that follows.
affect: Correct. After the article no and the adjective noticeable, a noun is needed. Effect is the noun (a result); affect is usually a verb (to influence). Corrected: "had no noticeable effect on the patient's blood pressure."
patient's: Patient's correctly shows singular possession: the blood pressure belongs to one patient.
Affect is usually the verb (The drug affects blood pressure); effect is usually the noun (The drug has an effect). A noun slot after an article or adjective calls for effect.
In pea plants, the allele for tall stems (T) is dominant to the allele for short stems (t). The Punnett square shows a cross between a heterozygous tall plant and a short plant. What percentage of the offspring are expected to be short?
| t | t | |
|---|---|---|
| T | Tt | Tt |
| t | tt | tt |
Answer: B
25%: 25% (1 in 4) is the short fraction from a Tt × Tt cross. This cross has a homozygous short parent, so more offspring are short.
50%: Correct. Two of the four boxes are tt, and only tt plants are short. 2 ÷ 4 = 50%.
75%: 75% would be the tall fraction from a Tt × Tt cross. Here only half the offspring receive a T allele.
100%: Every offspring gets a t from the short parent, but half also get a T from the other parent. Those Tt plants are tall.
A heterozygote crossed with a homozygous recessive (a test cross) gives a 1 : 1 ratio of dominant to recessive phenotypes.
In aerobic cellular respiration, which stage produces the most ATP per molecule of glucose?
Answer: C
Glycolysis: Glycolysis gives a net gain of only 2 ATP per glucose. It happens in the cytoplasm and does not need oxygen.
Krebs (citric acid) cycle: The Krebs cycle makes only about 2 ATP per glucose directly. Its main job is to load NADH and FADH₂ with high-energy electrons.
Electron transport chain: Correct. The electron transport chain and chemiosmosis on the inner mitochondrial membrane produce about 32–34 ATP per glucose, by far the most. Oxygen is the final electron acceptor.
Pyruvate oxidation: Converting pyruvate to acetyl-CoA releases CO₂ and makes NADH, but it produces no ATP directly.
Most ATP in aerobic respiration comes from oxidative phosphorylation in the electron transport chain, which depends on oxygen as the final electron acceptor.
When the equation is balanced with the smallest whole-number coefficients, what is the coefficient of ?
Answer: B
3: 3 is the coefficient of , set by the 3 carbon atoms in propane. It is not the coefficient of .
5: Correct. The balanced equation is , with 10 O atoms on each side.
7: This comes from writing 8 H₂O and forgetting that each water has 2 H atoms. Then O on the right is 6 + 8 = 14 (so 7 O₂), but H would be 16 on the right and 8 on the left.
10: 10 is the number of oxygen atoms needed. Each molecule supplies 2 atoms, so only 5 molecules are needed.
For a hydrocarbon combustion, balance C first, then H, then O last, because appears alone and is easiest to adjust.
The figure shows a simplified anterior view of the four heart chambers. What is the function of the chamber labeled 2?
Answer: A
It pumps deoxygenated blood into the pulmonary trunk.: Correct. Chamber 2 is the right ventricle: it is a lower chamber on the patient's right (viewer's left) and holds deoxygenated blood, which it pumps through the pulmonary valve into the pulmonary trunk toward the lungs.
It receives deoxygenated blood from the venae cavae.: This describes the right atrium (chamber 1), the upper chamber on the patient's right. Atria receive blood; ventricles pump it out of the heart.
It receives oxygenated blood from the pulmonary veins.: This describes the left atrium (chamber 3). Choosing it comes from reading the viewer's left as the patient's left.
It pumps oxygenated blood into the aorta.: This describes the left ventricle (chamber 4), the lower chamber on the patient's left, which sends blood into the systemic circulation.
In an anterior view the patient's right side appears on the viewer's left; the right ventricle pumps deoxygenated blood to the lungs through the pulmonary trunk.
In anatomical position, the sternum is ______ to the vertebral column.
Answer: B
posterior: Posterior means toward the back. The vertebral column is posterior to the sternum, so this reverses the relationship.
anterior: Correct. Anterior (ventral) means toward the front of the body. The sternum lies in the front of the chest wall, in front of the vertebral column.
lateral: Lateral means farther from the midline. Both the sternum and the vertebral column lie on the midline, so neither is lateral to the other.
inferior: Inferior means lower, toward the feet. The two structures are compared front to back here, not top to bottom.
Anterior and posterior describe front-to-back position; the sternum sits in front of the vertebral column on the same midline.
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