Chemistry Basics Quiz

Introduction

• This unit covers basic chemistry concepts, SI units, measurement uncertainties, scientific methods, lab equipment, and safety. Mastery ensures accurate experiments.

Formulas and Equations

• Density: d = m/V, where d is density, m is mass, and V is volume.
• Temperature Conversion: K = °C + 273.15; °C = (°F - 32)/1.8
• Volume of a Sphere: V = (4/3)πr³

Precision and Accuracy

• Precision: The consistency of repeated measurements.
• Accuracy: How close a measurement is to the true value.
• Demonstrating both precision and accuracy means measurements consistently close to the true value.

SI Units and Their Prefixes

• SI Units: There are seven base SI units used in chemistry: meter (m), kilogram (kg), second (s), ampere (A), kelvin (K), mole (mol), candela (cd).
• Prefixes: SI units use prefixes to indicate multiples or fractions (e.g., kilo = 10³, milli = 10^-3, nano = 10^-9).

Scientific Notation

• Used for very large or very small numbers to simplify calculations.
• Example: 6.02 x 10²³ (Avogadro's number) or 3.27 x 10^-22

Significant Figures Rules

• Non-zero digits: Always significant.
• Zeros between significant digits: Significant.
• Leading zeros: Not significant.
• Trailing zeros in a decimal number: Significant.

Derived SI Units

• Area: Length squared (m²)
• Volume: Length cubed (m³)
• Density: Mass per unit volume (kg/m³)
• Speed: Distance traveled per unit time (m/s)
• Acceleration: Speed changed per unit time (m/s²)
• Force: Mass times acceleration (kg⋅m/s² = N)
• Pressure: Force per unit area (kg/(m⋅s²) = Pa)
• Energy: Force times distance traveled (kg⋅m²/s² = J)

Uncertainty in Measurements

• Systematic Uncertainties: Consistent deviations that can be corrected (e.g., calibration errors).
• Random Uncertainties: Unpredictable variations that can be reduced but not eliminated.
• Significant Figures: The meaningful digits in a measurement, indicating the precision of the measurement.

Summary

• SI Units: Seven base units (m, kg, s, A, K, mol, cd) and prefixes.
• Measurements: Systematic and random uncertainties and significant figures.
• Precision and Accuracy: Consistency and closeness to true values in measurements.
• Scientific Notation: Simplifies calculations for large/small numbers.
• Temperature Scale Celsius converted to Kelvin using K = °C + 273.15