Chemistry 1LD Practice Test

These questions are part of the practice quiz. Start practicing

• If 5.00 g of H2 reacts with excess O2 to form water, what mass of H2O is produced?
• What is the purpose of a risk assessment?
• Which item is flammable?
• Which element in the second period has the highest first ionization energy?
• How many valence electrons are in the sulfate ion SO4^2−?
• On the NFPA rating system, what does the number 4 in the red (flammability) section indicate?
• For a 0.350 m solution, calculate boiling-point elevation ΔTb using Kb = 0.512 °C kg/mol and i ≈ 2.
• In alpha decay, 238U decays to 234Th. What is the emitted particle and the Z and A of the daughter nucleus?
• If 4.00 g of NaCl are dissolved to make 2.00 L of solution, what is the molarity?
• For the gas-phase equilibrium 2 NO2(g) ⇌ N2O4(g), at equilibrium [NO2] = 0.200 M and [N2O4] = 0.100 M. Calculate Kc.
• Which statement correctly describes LD50 and LC50?
• At STP, one mole of an ideal gas occupies what volume?
• What is the mass percent of oxygen in CH2O?
• Which of the following statements best defines acute toxicity?
• Which is a component of risk management in the lab?
• A reaction has theoretical yield 2.75 g CO2; actual yield is 2.20 g. What is the percent yield?
• Which statement defines a toxin?
• A container contains 0.60 m NaCl; given Kf = 1.86 °C/m and i ≈ 2, what is the freezing-point depression ΔT_f?
• Which substance bioaccumulates in the body?
• If 1.00 g CH4 is combusted, how many grams of CO2 are theoretically produced? (CH4 + 2 O2 → CO2 + 2 H2O; M_CH4 = 16.04 g/mol; M_CO2 = 44.01 g/mol)
• Which term describes substances that can trigger immune hypersensitivity?
• In a chemistry lab, which footwear is recommended to protect your feet?
• Which group has the most negative electron affinity values?
• Which statement correctly defines molality and molarity?
• A gas of 1.00 g mass occupies 1.00 L at 298 K and 1 atm. Estimate the molar mass from PV = nRT (use n = PV/RT).
• Nitrile gloves may be degraded by acetone.
• If a gas is warmed from 298 K to 348 K at constant pressure, by what factor does its volume change?
• Which practice is most aligned with green chemistry in laboratory work?
• What does OEL stand for?
• Which of the following is an intensive property?
• Corrosives can cause severe tissue damage on contact. Which statement about safe handling is true?
• What does IDLH stand for?
• In a buffer, if [A-] equals [HA], pH equals?
• At STP, a gas has density 0.50 g/L. Approximately what is its molar mass?
• Risk level is calculated by multiplying hazard severity by which factor?
• A gas sample with volume 1.00 L contains 0.50 g of gas at STP. What is its density in g/L?
• In the galvanic cell described, which half-reaction occurs at the anode?
• What is a hazard?
• A 2.00 L container holds 0.800 moles of an ideal gas at 298 K. What is the pressure?
• To reach the equivalence point in the titration of 25.0 mL of 0.100 M NaOH with 0.100 M HCl, what volume of HCl is required?
• During a chemical spill in the lab, which action is appropriate if it is safe to do so?
• In green chemistry, which description best captures an energy-efficient approach to reaction design?
• Which substance bioaccumulates in the body?
• Which salts are soluble in water?
• In the reaction 2 H2 + O2 -> 2 H2O, what is the mole ratio of H2O to H2?
• In a strong acid–base titration, 25.0 mL of 0.100 M NaOH is titrated with 0.100 M HCl. What is the pH at the equivalence point?
• A 2.00 L container holds 0.500 moles of an ideal gas at 298 K. What is the pressure?
• At constant pressure, heating a gas from 25°C to 100°C changes its volume by what factor?
• Which value represents Avogadro's number?
• What should you do when a fire alarm sounds in the lab if it is safe to do so?
• Which statement about glove materials is true?
• The rate law for A + B → products is rate = k[A]^m[B]^n. If doubling [A] (with B constant) doubles the rate, what is the order with respect to A?
• Which statement best describes the enthalpy change for methane combustion reaction CH4 + 2 O2 → CO2 + 2 H2O(l)?
• Which is a sensitizer?
• Which hazard category causes irreversible damage to the eye?
• Which chemical has the lowest permissible exposure limit (PEL) among the following: Hexane, Dichloromethane, Ethyl acetate, Methanol?
• Balance the redox reaction in acidic solution: MnO4- + Fe2+ → Mn2+ + Fe3+. Which is the balanced equation in acidic solution?
• Using Henderson–Hasselbalch, a buffer is prepared with 0.100 M acetic acid (HA) and 0.200 M acetate (A-). If pKa = 4.74, what is the pH?
• Which substance is metabolized and removed by the liver?
• Which chemical has the highest odor threshold among the following: Hexane, Dichloromethane, Ethyl acetate, Methanol?
• Which expression correctly represents freezing-point depression ΔTf?
• In a gas mixture at STP, what volume does 0.50 moles of an ideal gas occupy?
• Which option is an example of using renewable feedstocks?
• Mass percent is defined as the mass of solute per what quantity, multiplied by 100?
• In the NFPA hazard diamond, which color is used to indicate flammability?
• For Ethyl acetate, the odor threshold is lower than its PEL.
• Toxicity is defined as the ability of a chemical to:
• A 0.75 g sample of a gas occupies 0.40 L at 298 K and 1 atm. What is its approximate molar mass?
• Odor threshold is the lowest concentration at which a chemical's odor is detectable by humans.
• Doubling the amount of CH4, while O2 is in excess, affects the enthalpy change ΔHrxn as follows.
• Which statement best describes the concept used for standard enthalpy of formation?
• The standard cell potential for the galvanic cell Zn(s) | Zn2+ (1 M) || Cu2+ (1 M) | Cu(s) is E°cell = 1.10 V. Write the spontaneous reaction and confirm E°cell sign.
• A metal sample of mass 50.0 g is heated from 25.0 °C to 100.0 °C. If the metal has a specific heat capacity of 0.385 J/g·K, how many joules of heat are required?
• Which term indicates the severity of a chemical hazard?
• A compound is 40.0% C, 6.7% H, 53.3% O by mass. Determine its empirical formula.
• At STP, what is the density in g/L of a gas with molar mass 22.4 g/mol?
• A solution has 0.500 moles of solute in a total volume of 1.50 L. What is its molarity?
• Which condition is preferred in green chemistry to reduce energy usage?
• In risk management, which principle states that risk allowed increases with benefit?
• Which is a carcinogen?
• How is risk defined in safety terms?
• What does zero risk mean?
• If 58.44 g of NaCl is dissolved in enough water to make 1.50 L of solution, what is the final molarity?
• Given 3.00 g of N2H4 (MW 32.05) and 5.00 g of O2 (MW 32.00) react according to N2H4 + O2 -> N2 + 2 H2O. Which is the limiting reagent and how many grams of N2 are produced?
• LD50 refers to the lethal dose that kills what percentage of the test population?
• At STP, what volume does 0.75 moles of an ideal gas occupy?
• Which statement best defines odor threshold?
• Which term describes a chemical that can trigger an adverse immune response, causing hypersensitivity?
• How many electrons can occupy the 4p subshell, and what are the possible ml values for these orbitals?
• Define the limiting reagent.
• In a 100.0 g sample of solution, 58.5 g NaCl is present. What is the mass percent of NaCl?
• Which statement about flammable liquids and their vapors is accurate?
• Which statement best describes the purpose of GHS hazard pictograms?
• Which term best describes a chemical producing toxin effects?
• Which hazard class is defined by causing birth defects?
• In CH4 + 2 O2 → CO2 + 2 H2O, what is the mole ratio of CO2 produced to CH4 consumed?
• Which hazard can be fatal if swallowed or if it enters the airways?
• Which is a teratogen?
• Which value represents the molar volume of a gas at STP?
• Which statement is an example of an occupational exposure limit (OEL) value?
• In GHS hazard categorization, which category number indicates an extremely flammable chemical?
• Which category best describes carbon monoxide?
• Which hazard category is associated with birth defects?
• How much heat is required to vaporize 10.0 g of water at 100 °C? ΔHvap = 40.7 kJ/mol; M(H2O) = 18.015 g/mol
• Which statement about toxicity is true?
• Which is a neurotoxin?
• LC50 refers to the lethal concentration that kills what percentage of test animals?
• What does Avogadro's number specify?
• What does odor fatigue describe?
• Which is an asphyxiant?
• Permeation is defined as the ability of a chemical to seep through the glove.
• If [OH−] = 1.0×10^−3 M, what are the pH and pOH of the solution?
• Which group typically shows the most negative electron affinity values, and why?
• Which statement about risk is true?
• Which statement best describes a principle of green chemistry?
• Which hazard category is described by having the potential to cause cancer or being a presumed human carcinogen?
• Which hazard term describes chemicals that cause harm to particular organs?
• In the redox reaction MnO4- + 5 Fe2+ + 8 H+ → Mn2+ + 5 Fe3+ + 4 H2O, how many electrons are transferred?
• Degradation is defined as the destructive change in the glove material.
• Which substance is correctly classified as a carcinogen?
• Using Henderson-Hasselbalch equation, if pH = 5.00 and pKa = 4.74, what is the ratio [A−]/[HA]?
• For the reaction CH4 + 2 O2 → CO2 + 2 H2O(l), calculate ΔHrxn using ΔHf° values: ΔHf°(CO2) = -393.5 kJ/mol, ΔHf°(H2O,l) = -285.8 kJ/mol, ΔHf°(CH4) = -74.8 kJ/mol.
• Which statement best captures a core goal of green chemistry?
• Corrosives can cause severe tissue damage on contact. Which effect is characteristic of corrosives?
• For boiling-point elevation with i ≈ 2 and Kb = 0.512 °C kg/mol, what is ΔTb for a 0.350 m solution?
• What is toxicology?
• A gas sample has density 1.96 g/L at 298 K and 1 atm. What is its molar mass?
• Which term describes a toxic substance made by living organisms?
• Which hazard type is fatal if exposed to small amounts?
• What does PEL stand for in occupational safety?
• Which of the following is a common practice in risk management?
• Breakthrough time is defined as the time for first appearance of the chemical on the skin through the glove.
• Which is a poison?
• Which practice reduces the environmental impact of chemical reactions?
• If a solution has 58.5% NaCl by mass and you have 200.0 g of this solution, how many grams of NaCl are present?
• Which statement is true about green chemistry principles?
• Which of the following is an extensive property?
• What is the ground-state electron configuration for Fe2+ in noble-gas shorthand?
• Which statement about green chemistry principles in typical chemistry lab experiments is true?
• Using PV = nRT, calculate the pressure for n = 0.200 mol in V = 5.00 L at T = 298 K.
• To reduce the probability of exposure to a hazard, which of the following must be assessed?
• In a buffer where pH equals pKa, what is the ratio [A−]/[HA]?
• If the activation energy Ea = 42 kJ/mol and temperature rises from 298 K to 348 K, estimate the factor by which k increases (use k2/k1 ≈ exp[-Ea/R(1/T2 - 1/T1)]).
• Which factor most directly affects the probability of a lab accident?
• If a gas has 0.5 mole at STP, what volume does it occupy?
• Which statement correctly distinguishes permeation from rate of transfer?
• Which symbol indicates flammable substances under the Global Harmonized System (GHS) pictograms?
• Which option best defines a hazard?
• Which chemical has the lowest odor threshold among the following: Hexane, Dichloromethane, Ethyl acetate, Methanol?
• Which statement is true about flammable terminology?
• Which hazard category is associated with producing genetic defects?
• Chronic toxicity refers to harmful effects that occur after:
• Which statement best describes the aim of green chemistry?
• Which hazard category best describes agents that cause damage to specific organs?
• Which statement correctly pairs a substance with its attribute?
• A 0.10 M solution of acetic acid (Ka = 1.8×10^-5) is prepared. What is its pH?
• Which statement describes proper practice when using a fume hood?
• Which option is not aligned with green chemistry principles?
• What factors determine risk level?
• Acute toxicity is best described as the ability to harm or kill an organism after:
• How much heat is required to melt 5.00 g of ice at 0 °C? ΔHf°(ice) = 6.01 kJ/mol; M = 18.015 g/mol
• A 0.010 M solution of a strong acid (HCl) has what pH?
• Which statements about responding to lab emergencies are true?
• Risk assessment primarily involves what?
• Which substance is metabolized to calcium?
• In risk management, which approach sets exposure levels to what is feasible?
• Which statement correctly describes ethylene glycol?
• Which guidelines should be followed to protect your skin in the chemistry lab?
• Which hazard category is known to cause cancer or be presumed carcinogenic to humans?
• Which PPE practice is essential when handling corrosive chemicals in the laboratory?
• Which tool helps determine hazard severity?
• Which hazard class is associated with causing genetic mutations?
• What is the standard enthalpy of formation?
• Which statement about green chemistry and waste/recycling is true?
• At STP, how many liters does 2 moles of an ideal gas occupy?
• Rate of transfer refers to the speed at which a chemical seeps through.
• Which term describes a chemical producing toxin effects?
• Which is an organ toxicant?
• Determine the oxidation state of chromium in potassium dichromate, K2Cr2O7.
• A gas in a closed container is heated from 298 K to 450 K at constant volume. If initially P = 1.00 atm and V fixed, what is the final pressure?