IB Chemistry Quiz: Using Technology In Chemistry

What this quiz covers

This quiz focuses on Using Technology In Chemistry, giving you a quick way to practice the rules, question types, and explanations that matter most for IB Chemistry.

How to use this quiz

Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

Question 1

1. A red filter, because red light is strongly absorbed by the purple solution, maximizing the change in absorbance readings.
2. A blue filter, because blue light is a component of purple, so its transmission will accurately reflect the reactant concentration.
3. A green filter, because green is the complementary colour to purple, so this wavelength will be most strongly absorbed. (correct answer)
4. No filter is needed, as the colorimeter automatically detects the wavelength of maximum absorbance for any coloured solution.

Question 2

1. Inaccurate reading of the temperature from the digital display, causing random errors in ΔT.
2. Heat loss from the calorimeter to the surroundings, which is a systematic error not measured by the probe. (correct answer)
3. Fluctuations in the probe's calibration, leading to inconsistent temperature readings throughout the experiment.
4. The digital probe has a slow response time, failing to capture the true maximum temperature reached during the reaction.

Question 3

1. Simulations are based on approximations of quantum mechanics and may not perfectly replicate real-world intermolecular forces. (correct answer)
2. The software cannot calculate molecular properties like polarity or bond energy, only bond angles and lengths.
3. Computational models require significant processing power, making them less accessible than simple experimental methods.
4. The model is static and cannot provide information about the vibrational states of the molecule's bonds.

Question 4

1. Mass spectrometry, by monitoring the decrease in the m/z value of the molecular ion peak as hydrogen is removed.
2. Ultraviolet (UV) spectroscopy, by observing the appearance of a peak corresponding to the π → π* transition in the product.
3. Infrared (IR) spectroscopy, by monitoring the disappearance of the broad O-H stretch and the appearance of the sharp C=O stretch. (correct answer)
4. ¹H NMR spectroscopy, by measuring the decrease in the integration value for the signals corresponding to methyl protons.

Question 5

1. It calculates the enthalpy of neutralization in real-time, eliminating the need for post-experiment calculations.
2. It allows for the simultaneous collection of time-synchronised data, revealing the relationship between pH change and temperature increase. (correct answer)
3. It automatically adjusts the rate of addition of NaOH to maintain a constant pH, making the reaction easier to control.
4. It reduces the amount of reactants needed for the experiment because the high-precision sensors can detect very small changes.

Question 6

1. The uncertainty in the molar mass of the solid, as given on the periodic table.
2. The possibility of not dissolving all the solid completely before making up to the mark.
3. Random fluctuations in the last decimal place of the digital balance reading.
4. The inherent uncertainty in the calibration of the 250.0 cm³ volumetric flask. (correct answer)

Question 7

1. It completely eliminates systematic errors, such as using an uncalibrated pipette, ensuring higher accuracy.
2. It can use a wider range of chemical indicators, including those whose colour changes are difficult for the human eye to detect.
3. It improves precision by delivering titrant with a motorised burette and detecting the endpoint electronically, minimizing random operator-dependent variations. (correct answer)
4. It significantly speeds up the chemical reaction itself, allowing for a much faster determination of the endpoint.

Question 8

1. The software calculates the activation energy directly from the slope of the concentration versus time graph.
2. It identifies the plot that yields the best straight-line fit, the linearity of which is characteristic of a specific reaction order. (correct answer)
3. It determines the half-life of the reaction, which is always constant for any reaction order and can be used to find the rate constant.
4. By integrating the area under the concentration versus time curve, the software directly provides the numerical value of the reaction order.

Question 9

1. Accept the computer's identification as definitive proof, as spectral databases are highly accurate and reliable.
2. Synthesize propan-1-ol from scratch and compare its smell and color to the unknown sample to confirm the identity.
3. Repeat the IR scan on a different brand of spectrometer to ensure the result is not an instrument-specific error.
4. Run a ¹H NMR spectrum of the sample to confirm the structure, as IR spectroscopy alone is not sufficient for unambiguous identification of isomers. (correct answer)

Question 10

1. The pH probe provides a precise pH value at the exact moment the indicator changes colour, confirming the indicator's accuracy.
2. The data logger generates a continuous titration curve, allowing the equivalence point to be determined graphically from the point of maximum slope, which is more objective than a colour change. (correct answer)
3. The technology eliminates the need for a buffer region calculation, as the equivalence point is simply the highest pH value recorded.
4. The data logger can record pH values faster than the base can be added, preventing over-titration and ensuring the final volume is the true equivalence point.

Question 11

1. Measuring the initial conductivity of both solutions; the HCl solution will have a significantly higher conductivity due to a greater concentration of mobile ions. (correct answer)
2. Titrating both acids with a strong base while monitoring conductivity; the equivalence point for both will occur at the minimum conductivity value.
3. Diluting both solutions by a factor of 10 and measuring the conductivity; the conductivity of the HCl solution will decrease by a factor of exactly 10.
4. Heating both solutions and observing the change in conductivity; the weak acid's conductivity will increase more sharply due to a shift in equilibrium.

Question 12

1. The retention time of each peak is directly proportional to the concentration of the corresponding component.
2. The area under each peak is integrated, and this area is proportional to the amount or concentration of the component. (correct answer)
3. The height of each peak is measured, as peak height is a universal constant for one mole of any substance.
4. The number of peaks in the chromatogram directly gives the percentage by mass of each component in the mixture.

Question 13

1. The technology is not useful as both compounds have a nominal mass of 74 and the difference is within the instrument's margin of error.
2. The instrument measures the isotopic distribution, and the compound with a larger M+2 peak due to its two oxygen atoms is identified as the diol.
3. The mass spectrometer fragments the molecules, and the compound that produces a fragment with a mass of 30 (NO⁺) is identified as propanamide.
4. By calculating the precise theoretical masses, the experimental mass can be matched to one of the compounds, differentiating them based on their exact mass. (correct answer)

Question 14

1. The initial rate cannot be determined because the sensor only measures the final pressure of O₂ after the reaction is complete.
2. The method is inaccurate because the pressure of water vapour will interfere with the oxygen gas measurement, leading to an artificially high rate.
3. The initial rate is determined from the gradient of the tangent to the pressure-time curve at t = 0, as pressure is directly proportional to the moles of O₂ produced. (correct answer)
4. The rate can only be calculated by converting pressure to concentration using the ideal gas law, requiring the flask to be submerged in an ice bath to maintain standard temperature.

Question 15

1. Infrared (IR) spectroscopy, by identifying the unique C=O bond stretch frequency for each isomer.
2. Mass spectrometry (MS), as the different bond locations will lead to different, predictable fragmentation patterns and fragment masses. (correct answer)
3. ¹H NMR spectroscopy, by comparing the total number of protons in each molecule, which will be different.
4. A high-precision digital balance, to determine the molar mass of the compound to several decimal places.

Question 16

1. A mercury-in-glass thermometer, because mercury has a high thermal conductivity and responds quickly to temperature changes.
2. A bimetallic strip thermometer, because its mechanical response is directly proportional to temperature and easy to read without electronic interference.
3. An alcohol-in-glass thermometer, because its large bulb provides a greater surface area for heat exchange, ensuring accuracy.
4. A digital temperature probe with a thermistor, because it has a low heat capacity, a fast response time, and can be logged continuously by a computer. (correct answer)

Question 17

1. By measuring the increasing absorbance of light as the white precipitate of BaSO₄ forms and makes the solution more opaque. (correct answer)
2. By measuring the decreasing pH of the solution as the solid barium sulfate is formed from its ions.
3. By measuring the increase in light emitted by the BaSO₄ precipitate, which is chemiluminescent.
4. By measuring the decreasing conductivity of the solution as the concentration of aqueous ions decreases.

Question 18

1. Determining the equivalence point of a titration between ethanoic acid and sodium hydroxide.
2. Measuring the mass change during the thermal decomposition of calcium carbonate.
3. Modeling the interaction of a potential new drug molecule with a protein's active site. (correct answer)
4. Identifying the products of combustion of a magnesium ribbon in air.

Question 19

1. The spectrometer measures the mass-to-charge ratio of proton fragments, which are then pieced together to form the structure.
2. The technology detects the energy absorbed by protons to flip their spin in a magnetic field, providing data on their chemical environment, relative numbers, and adjacent protons. (correct answer)
3. The instrument passes infrared radiation through the sample, and the resulting spectrum shows how many hydrogen atoms are in each functional group.
4. A computer database compares the ¹H NMR spectrum to millions of known spectra to find an exact match, which is the only reliable way to identify the molecule.