Step 1: Put on goggles and gloves, verify the burette is clean, and rinse it with the standard NaOH solution. Step 2: Record initial volume, secure a flask with measured vinegar sample and two drops of phenolphthalein; if the sample is cloudy, filter it before proceeding. Step 3: Begin titration, swirling constantly; if the indicator flashes pink then disappears, slow the drip rate to a drop every two seconds. Step 4: If you overshoot to a persistent magenta, discard the trial, rinse the flask, and repeat from Step 2; otherwise, stop when a faint pink persists for 30 seconds. Step 5: Record final volume; calculate molarity. If initial and final readings differ by less than 10 mL, flag the trial as suspect and redo. Step 6: If two valid trials agree within 5 percent, average them; if not, re-standardize NaOH, re-rinse the burette, and repeat the titration sequence before concluding.

Before beginning the titration in Step 3, which prerequisite sequence must be completed?

Step 1: Install the latest Arduino IDE, verify USB drivers, and fully charge the 6V battery pack. Step 2: Assemble the breadboard: connect the solar charge controller to the battery, the battery to a 5V buck converter, and the converter to the microcontroller VIN; if polarity is unclear, consult the wiring diagram and pause. Step 3: Attach the light sensor to A0 and an I2C display; if the code references a missing library, install it before compiling. Step 4: Upload firmware; if compilation fails, fix errors and confirm board and port settings; if upload times out, tap reset and retry. Step 5: Measure output with a multimeter; if voltage is under 4.8V, tune the buck converter; if above 5.2V, recalibrate. Step 6: Enter test mode and cover the sensor; if readings change and the display updates, begin logging; if not, rewire the sensor, reseat connections, and repeat calibration before deployment.

According to the procedure, what must be completed before compiling the code in Step 3?

Step 1: Confirm a flash flood warning via NOAA radio and activate the campus emergency plan; if there is a tornado warning instead, switch to the severe-wind plan. Step 2: Assign roles: runners, shelter managers, and first aid; if staffing is short, combine roles but maintain accountability logs. Step 3: Move students to interior, high-ground rooms; if water rises above door thresholds, relocate vertically but avoid attic spaces without exits. Step 4: Shut off main electricity only if the panel is dry and accessible; if any standing water is nearby, skip the shutoff and barricade the area. Step 5: Conduct headcounts; if a student is missing, notify incident command and search in pairs along the last known route. Step 6: After the all-clear, document injuries and damage; if utilities are compromised, do not release students until reunification protocols and safe pickup zones are established, with parent notification and transport coordination.

Before shutting off main electricity in Step 4, what condition must be verified?

Step 1: Flush the main line for two minutes to clear sediment; if water runs cloudy after two minutes, continue flushing until clear. Step 2: Install a clean filter cartridge and open the bypass momentarily to purge trapped air; if pressure spikes, close valves and reseat the cartridge. Step 3: With all emitters capped, set the regulator to 20 psi; if the well pump cycles rapidly, lower the setpoint to protect the pump. Step 4: Open one zone; if line pressure drops below 15 psi, replace clogged emitters and check for leaks before proceeding. Step 5: Place a graduated cylinder under three random emitters and run for 10 minutes; if average flow differs from spec by more than 10 percent, adjust the regulator and retest. Step 6: When two consecutive tests meet spec, uncap remaining emitters and schedule irrigation; if algae is visible, add filter maintenance to the weekly checklist.

Before running the 10-minute flow test in Step 5, what prerequisite must be satisfied?

Step 1: Put on goggles and gloves. Verify the NaOH label shows a current standardization; if not, standardize with KHP before proceeding. Step 2: Decide your detection method. If using a pH probe, calibrate with pH 4, 7, and 10 buffers now; otherwise, prepare phenolphthalein. Step 3: Pipette 25.00 mL of the unknown acid into a clean Erlenmeyer; add the indicator or insert the calibrated probe. Step 4: Rinse and fill the burette with standardized NaOH, remove any air bubble, and record the initial reading. Step 5: Titrate while swirling. If the endpoint is overshot, discard the trial and restart Step 3; otherwise, record the final burette reading. Step 6: Compute the acid molarity using $M_1V_1 = M_2V_2$. If two trials disagree by more than 0.02, perform a third. Record all data in your lab notebook, including temperatures and any anomalies, before cleaning glassware. Return chemicals to storage as directed.

According to the procedure, which action must be completed immediately before beginning Step 4 (filling and reading the burette)?

Step 1: Put on safety glasses, inventory the kit, and verify the 12‑volt generator and multimeter function; if anything is missing or dead, request replacements before proceeding. Step 2: Assemble the tower and nacelle, aligning the shaft. Decide whether you will measure voltage or current; set the multimeter accordingly. If using an anemometer, calibrate it now. Step 3: Solder two leads to the generator. Give the shaft a brief hand spin while measuring; if polarity reads negative, swap the leads. Step 4: Cut and attach three blades at a 15‑degree pitch. If wobble occurs, add a small balancing tab before testing. Step 5: Upload the data‑logging firmware to the microcontroller; if flashing fails, reinstall the driver and retry. Step 6: Test in front of a box fan. If output exceeds the target, reduce blade pitch; otherwise, record rpm and output in your spreadsheet for the UIL STEM run sheet today.

Which sequence correctly prepares the generator wiring and measurement setup before testing in Step 6?

Step 1: Secure IRB approval and prepare consent/assent packets. If approval is pending, pause the project. Define your sampling frame and inclusion criteria. Step 2: Pilot the survey with 5–10 respondents. Flag confusing items; if an item is misunderstood by two or more, revise it before continuing. Step 3: Train data collectors using a rubric on mock interviews. Calculate interrater reliability; if Cohen's kappa is $< 0.7$, retrain and retest. Step 4: Recruit participants via your sampling plan. Verify eligibility; if a participant is a minor, obtain guardian consent before the student's assent. Otherwise, collect adult consent. Step 5: Administer the survey and record a response ID. If anyone withdraws, stop immediately and mark the case incomplete. Step 6: De‑identify responses, store them on an encrypted drive, and back up. If missing data exceed 10 percent, schedule follow‑ups; otherwise, begin analysis. Document all revisions in a dated change log daily.

Before obtaining a minor's assent in Step 4, which prerequisite must be completed?

Step 1: Confirm the emergency alert references an airborne release from the refinery. Move everyone indoors. If anyone is outside downwind, route them crosswind to the nearest entrance first. Step 2: Shut all exterior doors and windows. Turn off HVAC; if the thermostat will not shut the fan off, cut power at the breaker. Step 3: Select an interior room with few windows. Seal doors, vents, and sockets with plastic sheeting and tape. Step 4: Start a timer and monitor official updates on battery radio. If eye or throat irritation develops, don available respirators; if a person shows severe symptoms, call 911 when reception is reliable. Step 5: Maintain shelter for 30 minutes after the last update or until an all‑clear. Step 6: Ventilate slowly by opening upper windows first. If strong odor persists, re‑seal and resume Step 4; otherwise, account for everyone and document the incident for safety records.

According to the procedure, what must you do before cutting power at the breaker to stop the HVAC?

Step 1: Verify safety prerequisites—goggles on, lab apron tied, and a clean burette rinsed with standardized NaOH. Step 2: Prepare the analyte by pipetting 25 mL of unknown acid into a flask, adding two drops of phenolphthalein. Step 3: If the pH meter passes calibration with pH 4 and 7 buffers, place the electrode in the flask; otherwise, recalibrate before proceeding. Step 4: Record the initial burette reading, then titrate while swirling, slowing to drops as the pH approaches 8.5. Step 5: If the solution flashes pink and fades within 30 seconds, continue in half‑drops until the faint pink persists for 60 seconds; else, pause and gently mix. Step 6: If you overshoot the endpoint, discard the trial and repeat from Step 2; if not, compute molarity using $M_1V_1=M_2V_2$, and document all readings in ink before cleaning glassware. Finally, label waste beakers and return acids to the designated cart safely.

Before placing the electrode in the flask during Step 3, what prerequisite must be satisfied?

Step 1: Install the USB driver and IDE, then connect the microcontroller; proceed only if your laptop lists the correct COM port. Step 2: Wire the pressure sensor to 3.3V, GND, and $A_0$; if your board lacks 3.3V, add a regulator before powering anything. Step 3: Open the STEM competition template sketch; if it fails to compile, add the vendor library, then verify again. Step 4: Upload firmware; if the board is not detected, try a data‑rated cable or change ports before retrying. Step 5: With the device powered, open Serial Plotter and run the pit‑safe calibration: keep tubing open to air, press reset, then seal the line; if readings drift more than 2 units in 30 seconds, reroute wires and repeat calibration. Step 6: Save the baseline value in code, label all wires, and secure strain relief so checks pass at inspection. Document pin mappings in your engineering notebook.

According to the procedure, what must be in place before you power anything in Step 2?