TEAS Chemistry practice questions

Atoms and the periodic table, bonds, reactions, states of matter, solutions, acids and bases. Chemistry is 8 of the 44 scored questions in TEAS Science.

scored questions

8

of Science's score

18%

for all of Science

60 min

1. 01Science · ChemistryArrange the following solutions in order from the LOWEST to the HIGHEST molarity. (Molar masses: NaCl = 58.5 g/mol, glucose = 180 g/mol.)+−

   Correct order:

   1. 0.015 mol of solute in 150 mL of solution
   2. 0.40 mol of KCl in 2.0 L of solution
   3. 18 g of glucose dissolved in enough water to make 250 mL of solution
   4. 250 mmol of HCl in 500 mL of solution
   5. 5.85 g of NaCl dissolved in enough water to make 100 mL of solution

   The molarities are B = 0.015 mol/0.150 L = 0.10 M, D = 0.40 mol/2.0 L = 0.20 M, C = 0.10 mol/0.250 L = 0.40 M, E = 0.250 mol/0.500 L = 0.50 M, and A = 0.100 mol/0.100 L = 1.0 M. The largest amount of solute (D or E) does not give the highest concentration, because volume matters.

2. 02Science · ChemistryA mixture contains iron filings, table salt, and sand. Which procedure separates all three components?+−

   • A. Stir the dry mixture in water and filter it; evaporate the filtrate, then use a magnet on the recovered salt to remove the iron.
   • B. Filter the dry mixture, evaporate the remaining solid, and then use a magnet.
   • C. Dissolve the mixture in water, evaporate the water, and then use a magnet.
   • D. Use a magnet on the dry mixture to remove the iron; stir the remainder in water and filter out the sand; evaporate the filtrate to recover the salt. (correct)

   Magnetism removes the iron first, solubility then separates the salt from the sand by filtration, and evaporation recovers the salt. In the other options the iron stays mixed with sand, or sand and salt are never separated from each other.

3. 03Science · ChemistryAt standard temperature and pressure (STP), 1 mol of an ideal gas occupies 22.4 L. A 5.6 L sample of an unknown pure gas at STP has a mass of 11 g. Which gas is it? (Atomic masses: H = 1, C = 12, O = 16, S = 32.)+−

   • A. CH4
   • B. O2
   • C. CO2 (correct)
   • D. SO2

   5.6 L ÷ 22.4 L/mol = 0.25 mol, so the molar mass is 11 g ÷ 0.25 mol = 44 g/mol, which matches CO2 (12 + 2 × 16). O2 (32 g/mol) would have a mass of 8 g for this amount.

4. 04Science · ChemistryElectronegativity values are H = 2.1, C = 2.5, N = 3.0, and O = 3.5. Which choice correctly identifies the most polar of the bonds listed and the atom that carries the partial negative charge?+−

   • A. N–H, with the nitrogen atom partially negative
   • B. O–H, with the hydrogen atom partially negative
   • C. O–H, with the oxygen atom partially negative (correct)
   • D. C–H, with the carbon atom partially negative

   The O–H bond has the largest electronegativity difference (1.4), and the more electronegative oxygen attracts the shared electrons and becomes partially negative. C–H assigns the charge correctly but has the smallest difference (0.4), so it is the least polar.

5. 05Science · ChemistryElement Q has two naturally occurring isotopes: one with a mass of 69.0 amu and an abundance of 60.0%, and one with a mass of 71.0 amu and an abundance of 40.0%. What is the average atomic mass of Q, to the nearest tenth?+−

   Answer: 69.8 amu

   The weighted average is (69.0 × 0.600) + (71.0 × 0.400) = 41.4 + 28.4 = 69.8 amu. A simple average of 70.0 would ignore the abundances.

6. 06Science · ChemistryHeating calcium carbonate decomposes it according to CaCO₃ → CaO + CO₂. A student heats 250 g of CaCO₃ (molar mass 100 g/mol) and collects 88 g of CO₂ (molar mass 44 g/mol). What is the percent yield of CO₂?+−

   • A. 35%
   • B. 44%
   • C. 80% (correct)
   • D. 125%

   250 g is 2.50 mol of CaCO₃, which should give 2.50 mol × 44 g/mol = 110 g of CO₂ in a 1:1 ratio. The percent yield is 88 ÷ 110 × 100 = 80%. Dividing 88 by the 250 g of reactant gives 35%, which ignores the molar masses.

7. 07Science · ChemistryConsider the reaction HSO₄⁻ + CO₃²⁻ → SO₄²⁻ + HCO₃⁻. According to the Brønsted–Lowry definition, which species acts as a base in the forward reaction, and what is its conjugate acid?+−

   • A. HSO₄⁻; SO₄²⁻
   • B. CO₃²⁻; HCO₃⁻ (correct)
   • C. CO₃²⁻; H₂CO₃
   • D. HSO₄⁻; H₂SO₄

   CO₃²⁻ accepts one proton from HSO₄⁻, so it is the base, and the species it becomes, HCO₃⁻, is its conjugate acid. H₂CO₃ would require two protons to be gained, and HSO₄⁻ is the acid here, with SO₄²⁻ as its conjugate base.

8. 08Science · ChemistryA rigid tank at constant temperature contains 8.0 g of O₂ (molar mass 32 g/mol) and 14 g of N₂ (molar mass 28 g/mol). The total pressure is 3.0 atm. What is the partial pressure of O₂?+−

   • A. 0.75 atm
   • B. 1.0 atm (correct)
   • C. 1.1 atm
   • D. 2.0 atm

   There are 0.25 mol of O₂ and 0.50 mol of N₂, so O₂ is 0.25 ÷ 0.75 = 1/3 of the moles and exerts 1/3 × 3.0 atm = 1.0 atm. Using mass fractions (8 ÷ 22) gives 1.1 atm, but partial pressure depends on moles, not mass.

9. 09Science · ChemistryEthane (H3C-CH3), ethene (H2C=CH2), and ethyne (HC≡CH) contain a carbon-carbon single bond, double bond, and triple bond, respectively. Which statement correctly compares the carbon-carbon bonds?+−

   • A. The triple bond is the longest and the strongest.
   • B. The single bond is the shortest and the strongest because it involves only one shared pair.
   • C. The triple bond is the shortest and the strongest, and the single bond is the longest and the weakest. (correct)
   • D. All three bonds have the same length and differ only in the number of shared electrons.

   More shared electron pairs hold the two nuclei more tightly, so the bond is shorter and takes more energy to break. Choice A is wrong because more shared pairs shorten the bond rather than lengthen it.

10. 10Science · ChemistryLithium, sodium, and potassium are all found in the same vertical column of the periodic table. Which characteristic do atoms of these three elements share?+−

    • A. The same number of valence electrons (correct)
    • B. The same number of occupied energy levels
    • C. The same atomic mass
    • D. The same number of protons

    Elements in the same group have the same number of valence electrons (one for these three), which is why they react in similar ways. The number of occupied energy levels is what elements in the same period share, so B is wrong.

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Sources

1. ATI: ATI TEAS exam details (sections, questions, sub-areas)

Updated November 6, 2026