BCMB 419 Midterm Exam Review: Key Concepts and Techniques | Verified with 100% Correct Answers

BCMB 419 Midterm Exam Review: Key Concepts and Techniques | Verified with 100% Correct Answers What is accuracy in measurement? Accuracy refers to how close a measured value is to the true or accepted value. What does precision indicate in measurements? Precision indicates the reproducibility of measurements, or how close repeated measurements are to each other, regardless of their closeness to the true value. What is the target analogy in measurements? Every measurement consists of a number and a unit; the number tells us how much, and the unit tells us what we are measuring. What are significant figures? Significant figures are the digits in a measurement that carry meaning contributing to its precision, including all known digits plus one estimated digit. What are exact numbers? Exact numbers are known with complete certainty and do not have any uncertainty or need for rounding, such as counting items. How do you determine the number of significant figures in a measurement? The number of significant figures in a measurement is limited due to uncertainty; it includes all certain digits and the first uncertain digit. What is the rule for addition and subtraction regarding significant figures? In addition and subtraction, the answer must have the same number of decimal places as the measurement with the fewest decimal places. What is the rule for multiplication and division regarding significant figures? In multiplication and division, the answer must have the same number of significant figures as the value with the fewest significant figures. What is the purpose of a volumetric flask? A volumetric flask is used for making precise solutions and has high accuracy. What is the function of a graduated cylinder? A graduated cylinder is used for measuring volumes accurately and has medium accuracy. What are intensive properties? Intensive properties do not depend on the amount of substance present, such as density and boiling point. What are extensive properties? Extensive properties depend on the amount of substance present, such as mass and volume. What are colligative properties? Colligative properties depend on the concentration of solute molecules or ions but not on the identity of the solute. What is measurement uncertainty? Measurement uncertainty indicates how confident we are in the last digit of a measurement. What is systematic error? Systematic error causes results to deviate consistently from the true value in the same direction and can be challenging to detect. What are personal errors in measurement? Personal errors are caused by consistent habits or biases of the experimenter. What are random errors? Random errors cause replicate measurements to fluctuate around the mean of the dataset and are inherent in all experiments. What is destructive analysis? Destructive analysis is a method where the sample is damaged or consumed during analysis, such as burning a sample to measure its composition. What is the significance of calibration in measurements? Calibration ensures that measurement instruments provide accurate results by comparing them to known standards. What is the role of careful lab technique in minimizing errors? Careful lab technique and attention to detail are the best defenses against gross errors in measurements. What is the definition of molarity? Molarity is a measure of solute concentration defined as the number of moles of solute per liter of solution. What is chemical digestion? A process that breaks down food into smaller molecules without destroying the original structure. What are three characteristics of aqueous solutions that should always be noted? Temperature, ionic strength, and pH. What defines an acid in terms of proton donation? Acids are compounds that can donate a proton (H+). What is the pH scale range for acids and bases? Acids have a pH less than 7, while bases have a pH greater than 7. What does the ion product of water (Kw) equal at 25°C? Kw = 1.0 x 10^-14. How is pH affected by temperature? pH can change with temperature because more H+ and OH- ions are produced. How do strong acids and bases behave in solution? Strong acids and bases completely dissociate in solution. How do you calculate the pH of a strong acid? For a strong acid, pH = -log[H+]. For diprotic acids, multiply the concentration by 2. What is a buffer? A buffer is a solution that resists changes in pH when strong acids or bases are added. What is the Henderson-Hasselbalch equation used for? It is used to calculate the pH of a buffer solution. What is Good's Buffer? A group of buffers developed by Dr. Good that work well in living systems. What is the purpose of a pH meter? A pH meter measures the pH of a solution using a combination electrode. What is electromagnetic radiation? A form of energy that travels through space as oscillating electric and magnetic fields. How does energy relate to wavelength in electromagnetic radiation? Shorter wavelengths have higher energy, while longer wavelengths have lower energy. What is transmittance? The amount of light that passes through a substance. What is reflection in terms of electromagnetic radiation? Reflection is when electromagnetic radiation bounces off the surface of a material. What is absorption in the context of electromagnetic radiation? Absorption occurs when matter absorbs the energy of radiation, causing electronic, vibrational, or rotational transitions. What is diffraction? Diffraction is the bending or spreading of electromagnetic radiation waves around obstacles or through narrow openings. What is Rayleigh scattering? Rayleigh scattering occurs when light scatters off particles much larger than the wavelength of light, resulting in uniform scattering. What is Tyndall effect? The Tyndall effect is the scattering of light as it passes through a colloid, making the path of the light beam visible. What does ultraviolet-visible spectroscopy measure? It measures how much UV or visible light a sample absorbs, revealing information about its composition and concentration. What is a chromophore? A part of a molecule that absorbs specific wavelengths of light, causing the molecule to appear colored. What is the purpose of plotting absorbance against wavelength in spectrophotometry? To find the maximum absorbance (Xmax) and its corresponding wavelength. What does the Lambert-Beer Law relate to in spectrophotometry? It relates the absorbance of light to the molar absorption coefficient, molar concentration, and optical path length. What are chromophoric amino acids? Amino acids that contain side chains with chromophores, allowing them to absorb light.