Physical Science: Chemistry — Sample exam

A rehearsal paper with separate worked solutions; use it before the final.

24 questions · 48 points · suggested 90 minutes

Student instructions

Suggested time: 90 minutes; allow breaks or accommodations and record them.
Work independently with a calculator, blank paper and the reference relationships printed in this paper. Grades 9, 11 and 12 may also use the course-linked NYSED reference tables. Use no lesson notes or answer key during an assessed attempt.
Show reasoning and units for written tasks. All supplied datasets are illustrative; do not present them as measurements you collected.
Objective items: 1 point each. Written items: 3 points each, one per criterion. A parent or teacher marks the written work; the app never grades an explanation automatically.
Sample exam: try the whole paper before opening the worked key, then revisit the linked chapters. The sample and final are different papers; this is a course assessment, not an official Regents examination.

Reference relationships

Relationship, constant or reference	Use / conditions
Density	ρ=m/V; Mass and volume in consistent units
Amount	n=m/Mm; N=nNA; Mm is molar mass, not molarity
Concentration	M=n/V; M₁V₁=M₂V₂; Solution liters; dilution without reaction or loss
Ideal gas	PV=nRT; Kelvin and absolute pressure; R matched to units
Heating	q=mcΔT; qphase=mL; One phase versus phase change
Reaction heat	qreaction≈−qsurroundings; Include apparatus/loss terms when needed
Free energy	ΔG=ΔH−TΔS; Kelvin and matching energy units; not reaction rate
Equilibrium	Q, K=products/reactants with powers; Omit pure phases in the school approximation
Acidity	pH≈−log[H₃O⁺]; Concentration approximation; neutral near 7 at 25°C
Buffer	pH≈pKa+log([A⁻]/[HA]); Both conjugate species appreciable
Cell potential	E°cell=E°cathode−E°anode; Both table values are reduction potentials
Radioactive parent	N=N₀(½)^(t/thalf); Closed parent accounting; statistical model
NA=6.022×10²³ mol⁻¹	Avogadro constant, rounded for school calculations
h=6.626×10⁻³⁴ J·s	Planck constant, rounded
c=3.00×10⁸ m/s	Vacuum light speed, rounded
e=1.602×10⁻¹⁹ C	Elementary charge magnitude; 1 eV=1.602×10⁻¹⁹ J
g=9.8 m/s²	Typical near-surface Earth approximation; use a supplied local value if given
R=8.314 J/(mol·K)	Use SI pressure Pa and volume m³
R=0.0821 L·atm/(mol·K)	Use atmosphere pressure and liter volume
F≈96485 C/mol electrons	Faraday constant
1 u·c²≈931.5 MeV	Mass-energy conversion for consistent nuclear mass accounting
T(K)=T(°C)+273.15	Use 273 only when a question specifies that rounded convention
1 L=1000 mL; 1 mL=1 cm³	Volume conversions
1 kWh=3.60×10⁶ J	Energy conversion
cwater≈4.18 J/(g·°C)	Approximate liquid-water specific heat in ordinary conditions
Lf,water≈334 J/g; Lv,water≈2260 J/g	Water fusion and vaporization near ordinary-pressure transition conditions
H	1.008 g/mol
C	12.01 g/mol
N	14.01 g/mol
O	16.00 g/mol
Na	22.99 g/mol
Mg	24.31 g/mol
Al	26.98 g/mol
P	30.97 g/mol
S	32.06 g/mol
Cl	35.45 g/mol
K	39.10 g/mol
Ca	40.08 g/mol
Fe	55.85 g/mol
Cu	63.55 g/mol
Zn	65.38 g/mol
Ag	107.87 g/mol
NH₄⁺ / OH⁻ / NO₃⁻	Ammonium +1; hydroxide −1; nitrate −1
CO₃²⁻ / SO₄²⁻ / PO₄³⁻	Carbonate −2; sulfate −2; phosphate −3

Coverage and marks

Chapter	Questions	Points
Investigating Matter	1, 2	4
Atoms, Electrons & Periodicity	3, 4	4
Bonding, Formulas & Molecular Structure	5, 6	4
Reactions, Moles & Composition	7, 8	4
Stoichiometry & Yield	9, 10	4
States of Matter & Gases	11, 12	4
Solutions & Dissolved Particles	13, 14	4
Acids, Bases & Titration	15, 16	4
Chemical Energy & Thermodynamics	17, 18	4
Rates & Equilibrium	19, 20	4
Redox, Cells & Nuclear Chemistry	21, 22	4
Organic Chemistry & Material Design	23, 24	4

Name: ____________________ Date: ____________________

Question 1 · 1 point

A 18.0 g sample occupies 6.00 mL. Find density.

Question 2 · 3 points

Recover dry sand and salt from their mixture.

Question 3 · 1 point

Which particle has a mass roughly 1/1836 that of a proton?

nucleus
alpha particle
neutron
electron

Question 4 · 3 points

A supplied level diagram has states at 0, 2, and 5 energy units. List downward differences.

Question 5 · 1 point

When a chlorine atom gains one electron, the ion it forms is called…

a molecule
a cation
an anion
a proton

Question 6 · 3 points

Count valence electrons in CO₃²⁻.

Question 7 · 1 point

Which equation represents a combustion reaction?

CaCO₃ → CaO + CO₂
CH₄ + 2O₂ → CO₂ + 2H₂O
AgNO₃ + NaCl → AgCl + NaNO₃
2Na + Cl₂ → 2NaCl

Question 8 · 3 points

Would mixing aqueous NaNO₃ and KCl create a precipitate in the usual dilute model?

Question 9 · 1 point

For 2H₂ + O₂ → 2H₂O, how many moles of water form from 4.0 mol of hydrogen reacting with excess oxygen?

Question 10 · 3 points

Mix .010 mol HCl and .006 mol NaOH. Find acid excess.

Question 11 · 1 point

In the ideal-gas particle model, which state has particles far apart with intermolecular forces treated as negligible?

solid
liquid
gas
they are identical in all states

Question 12 · 3 points

Why does boiling water not keep warming under fixed pressure?

Question 13 · 1 point

A solution that contains the maximum amount of dissolved solute at a given temperature is described as…

nonpolar
unsaturated
saturated
dilute

Question 14 · 3 points

Compare equal molality NaCl and sugar ideally.

Question 15 · 1 point

In the Brønsted-Lowry model, a base is defined as a…

proton donor
proton acceptor
electron donor
hydroxide crystal

Question 16 · 3 points

Buffer pKa=4.76 and [A⁻]/[HA]=10. Estimate pH.

Question 17 · 1 point

How much heat (in J) is absorbed when 50.0 g of water is warmed from 15.0°C to 35.0°C? (c = 4.18 J/g°C)

Question 18 · 3 points

ΔH=40kJ/mol and ΔS=.080kJ/mol·K. Find crossover.

Question 19 · 1 point

According to collision theory, an effective collision requires…

enough energy and the correct orientation
that a catalyst be present
that the reaction be exothermic
only that the particles touch

Question 20 · 3 points

For K=4, current Q=.5, predict direction.

Question 21 · 1 point

Find carbon oxidation number in CO₂ using O=−2.

Question 22 · 3 points

Write the daughter counts for alpha decay of 238U with Z=92.

Question 23 · 1 point

Find hydrogen count for a simple acyclic alkane with seven carbon atoms.

Question 24 · 3 points

Reusable cup production impact is 500 units; disposable impact 10/use, reusable washing 2/use. Find break-even.

Revisit the covered chapters

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