Physical Science: Chemistry — Final exam

An independent assessment of the core chapters listed below, followed by corrections and discussion.

36 questions · 84 points · suggested 180 minutes

Student instructions

Suggested time: 120 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, 3	7
Atoms, Electrons & Periodicity	4, 5, 6	7
Bonding, Formulas & Molecular Structure	7, 8, 9	7
Reactions, Moles & Composition	10, 11, 12	7
Stoichiometry & Yield	13, 14, 15	7
States of Matter & Gases	16, 17, 18	7
Solutions & Dissolved Particles	19, 20, 21	7
Acids, Bases & Titration	22, 23, 24	7
Chemical Energy & Thermodynamics	25, 26, 27	7
Rates & Equilibrium	28, 29, 30	7
Redox, Cells & Nuclear Chemistry	31, 32, 33	7
Organic Chemistry & Material Design	34, 35, 36	7

Name: ____________________ Date: ____________________

Question 1 · 1 point

A 42.0 g sample occupies 15.0 mL. Find density.

Question 2 · 3 points

A 50.0 g solid displaces 20.0 mL water. Find density and describe an accuracy check.

Question 3 · 3 points

Separate salt and sand while preserving both solids. Explain why filtration alone is insufficient.

Question 4 · 1 point

Rutherford's gold-foil experiment, in which a few alpha particles bounced sharply backward, was the direct evidence for which idea?

Electrons exist as probability clouds
Atoms are indivisible solid spheres
An atom's mass and positive charge are concentrated in a tiny nucleus
Electrons travel in fixed orbits

Question 5 · 3 points

Isotopes at 35 u and 37 u occur in 75% and 25% abundance. Find average mass.

Question 6 · 3 points

Compare 400 nm and 800 nm photon energies and explain atomic line spectra.

Question 7 · 1 point

Which type of element usually forms a cation by losing electrons?

a halogen
a metal
a nonmetal
a noble gas

Question 8 · 3 points

Write aluminum nitrate and count oxygen atoms in two formula units.

Question 9 · 3 points

Explain why CO₂ is nonpolar while water is polar.

Question 10 · 1 point

Two or more simpler substances combine to form a single product, A + B → AB. What type of reaction is this?

synthesis
decomposition
single replacement
combustion

Question 11 · 3 points

Find an empirical formula from 24 g C and 8 g H using C=12 and H=1 g/mol.

Question 12 · 3 points

Write the net ionic equation when aqueous silver nitrate and sodium chloride produce solid AgCl.

Question 13 · 1 point

In the balanced equation N₂ + 3H₂ → 2NH₃, what is the mole ratio of H₂ to NH₃?

3 : 1
3 : 2
1 : 1
2 : 3

Question 14 · 3 points

N₂+3H₂→2NH₃ begins with 1 mol N₂ and 2 mol H₂. Find limiting reactant and maximum product.

Question 15 · 3 points

What volume of 0.10 M NaOH neutralizes 25 mL of 0.20 M HCl in a supplied-data problem?

Question 16 · 1 point

According to the kinetic molecular theory, the average kinetic energy of gas particles is directly proportional to the…

number of particles
Kelvin temperature
pressure of the gas
volume of the container

Question 17 · 3 points

Find volume of 1 mol ideal gas at 2 atm and 300 K with R=0.0821 L·atm/(mol·K).

Question 18 · 3 points

Melt 10 g ice at 0°C and warm the liquid to 10°C. Use Lf=334 J/g and c=4.18 J/(g·°C).

Question 19 · 1 point

In a solution of sugar dissolved in water, which part is the solvent?

the sugar
the water
the sweetness
the glass

Question 20 · 3 points

Find molality for 0.20 mol sugar in 0.50 kg water and ideal freezing depression with i=1, Kf=1.86.

Question 21 · 3 points

Why can salt water conduct while a sugar solution conducts poorly?

Question 22 · 1 point

An Arrhenius acid produces which ion when dissolved in water?

hydrogen ion, H⁺ (as H₃O⁺)
sodium ion, Na⁺
chloride ion, Cl⁻
hydroxide, OH⁻

Question 23 · 3 points

A buffer has pKa=4.8 and equal conjugate acid/base amounts. Estimate pH and state a limitation.

Question 24 · 3 points

Estimate pH for 0.010 M strong monoprotic acid at 25°C. Compare hydronium with pH 4.

Question 25 · 1 point

In an endothermic reaction, the sign of ΔH is…

negative
positive
always zero
impossible to determine

Question 26 · 3 points

A reaction warms 100 g water by 5°C. Use c=4.18 and neglect cup heat and losses. Find reaction heat.

Question 27 · 3 points

For ΔH=+20 kJ/mol, ΔS=+0.100 kJ/(mol·K), T=300 K, find ΔG. Does it determine rate?

Question 28 · 1 point

For a reaction whose rate increases with this reactant’s concentration, which change usually speeds it up while other conditions stay fixed?

removing the catalyst
cooling the reactants
using large chunks instead of a fine powder
increasing the concentration of a reactant

Question 29 · 3 points

For A⇌B, K=4 and current Q=0.5. Predict net direction and state the catalyst effect.

Question 30 · 3 points

Concentration falls from 0.80 to 0.20 M in 30 s. Find average disappearance rate.

Question 31 · 1 point

Find nitrogen oxidation number in NO₃⁻ with O=−2.

Question 32 · 3 points

Cathode and anode reduction potentials are +0.34 and −0.76 V. Find standard cell voltage and external electron direction.

Question 33 · 3 points

A 96 g parent isotope has half-life 5 years. Find parent after 15 years and state alpha-decay count changes.

Question 34 · 1 point

How many H atoms are in acyclic alkane C₆H…?

Question 35 · 3 points

Give the formula of a five-carbon acyclic alkane. Explain how ethanol and dimethyl ether can share a formula but differ in properties.

Question 36 · 3 points

Reusable production impact is 120 units plus 1/use; disposable is 5/use. Find break-even and two model limits.

Revisit the covered chapters

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