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The LLA exam has 70 questions and runs 2 hours.
These 10 free LLA questions are organized by exam domain, so you can see how each part of the Level I Laboratory Lubricant Analyst (LLA) blueprint is tested. Reveal the answer and explanation under each question.
An intact used-oil sample develops a visible sediment layer during storage. Its identification is verified, enough oil remains, and the deposit re-suspends using the laboratory's validated agitation procedure. The requested test is ASTM D893 insolubles. Which disposition preserves the requested measurement?
Correct answer: C - Re-suspend the deposit and promptly take a representative test portion.
A laboratory's validated ICP method accepts copper results only within 0.50-5.00 mg/kg in the diluted solution. Two independent preparations of one oil give these blank-corrected results before any dilution correction: preparation 1, 1.00 g oil plus 9.00 g diluent, 7.20 mg/kg; preparation 2, 1.00 g oil plus 19.00 g diluent, 3.60 mg/kg. The original-oil result equals the diluted result multiplied by total mixture mass divided by oil mass. Which reported copper result is supported by the method?
Correct answer: B - 72.0 mg/kg, calculated from preparation 2
Following a hydraulic system's switch from mineral oil to an ester-containing oil, its FTIR oxidation trend jumps. A pronounced band near 1740 cm⁻¹ is also present in retained unused replacement oil. Acid number and kinematic viscosity remain near the replacement oil's baseline values. What most likely caused the apparent jump in the oxidation trend?
Correct answer: B - Carbonyl absorption inherent in the ester formulation.
The requested report value is dynamic viscosity at 40°C. Verified measurements are 68.0 cSt at 40°C and 8.50 cSt at 100°C, with densities of 0.880 g/cm³ at 20°C and 0.860 g/cm³ at 40°C. Use η = ρν, where η is in cP, ρ in g/cm³ and ν in cSt. Which result uses a valid pairing of measurements, rounded to 0.1 cP?
Correct answer: A - 58.5 cP at 40°C
An oil-monitoring program reports in-service base number by ASTM D4739. The current result is 6.0 mg KOH/g; the supplier's unused-oil value is 9.2 mg KOH/g by ASTM D2896. A retained unused sample is available. To quantify depletion on the program's D4739 basis, which result is still needed?
Correct answer: D - Unused oil base number by D4739.
Coarse, iron-containing flakes are present in a used-oil sample, yet routine ICP-AES reports little iron. The sample was mixed and diluted correctly; the dissolved-iron control and reagent blank both passed. Which mechanism can account for the low measurement?
Correct answer: C - Under-recovery of large particles during routine ICP-AES analysis.
A 1 L bottle of toluene breaks outside a fume hood in an oil-analysis laboratory. A nearby analyst becomes dizzy but remains alert and able to walk. The spill is spreading toward an operating heater. You have incidental-spill training but are not an emergency responder. A clear exit is available without crossing the spill. What is the immediate priority?
Correct answer: D - Help the analyst use the clear exit, warn others to leave, and summon emergency assistance from a safe location.
A one-mark volumetric pipette is marked TD and is not a blow-out type. An analyst conditions it with the solution, sets the meniscus correctly, permits gravity drainage with the tip against the receiver wall, and completes the manufacturer's waiting and touch-off procedure. A small amount remains inside the tip. How should this transfer be completed?
Correct answer: A - Leave the residual liquid in the tip; the specified delivery procedure already accounts for that retained amount.
An elemental-analysis instrument passes its calibration checks using solutions prepared from one parent stock. A working check made by another analyst from that same stock also passes. A suitable certified check from a separate source fails repeatedly, including after fresh preparation; its lot, concentration, matrix and certificate have been checked. Which conclusion should govern release of the sample results?
Correct answer: A - The independent failure must be resolved before release; agreement among solutions from one stock can conceal an error shared by those solutions.
A viscosity station has action limits of 45.70-46.30 cSt and warning limits of 45.80-46.20 cSt. Its written procedure requires one fresh check after an isolated warning and permits continuation if that check is within the warning limits and no other chart signal is present. A check reads 46.24 cSt; the fresh check reads 46.08 cSt. No other QC criterion has failed. How should the analyst treat the warning and the run?
Correct answer: D - Retain both check results, document the follow-up, and continue the run as the procedure permits.
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