CHM 151 EXAM 1 QUESTIONS WITH VERIFIED SOLUTIONS LATEST UPDATE 2026
Chemistry - Answers The study of matter and the changes it undergoes
Observation - Answers Information gathered using senses
Law - Answers Describes what happens in nature
Hypothesis - Answers Tentative explanation for observations
Theory - Answers Well-tested explanation of why something happens
Macroscopic domain - Answers Observable, large-scale phenomena
Microscopic domain - Answers Atoms and molecules
Symbolic domain - Answers Chemical symbols, formulas, equations
Solid - Answers Fixed shape and volume; particles tightly packed
Liquid - Answers Fixed volume, takes shape of container
Gas - Answers Takes shape and volume of container; particles far apart
Mass - Answers Amount of matter in an object
Weight - Answers Force of gravity acting on an object
Law of Conservation of Matter - Answers Matter is neither created nor destroyed
Atom - Answers Smallest unit of an element that retains its properties
Molecule - Answers Two or more atoms bonded together
Element - Answers Pure substance made of one type of atom
Compound - Answers Substance made of two or more elements chemically bonded
Mixture - Answers Combination of substances physically mixed
Homogeneous mixture - Answers Uniform composition throughout
Heterogeneous mixture - Answers Non-uniform composition
Physical property - Answers Can be observed without changing identity
Chemical property - Answers Describes ability to undergo chemical change
Physical change - Answers Change in form but not identity
Chemical change - Answers Change that forms a new substance
Extensive property - Answers Depends on amount of matter
Intensive property - Answers Does not depend on amount
Quantitative measurement - Answers Includes numbers and units
Qualitative measurement - Answers Descriptive, no numbers
SI unit for length - Answers meter (m)
SI unit for mass - Answers kilogram (kg)
SI unit for time - Answers second (s)
SI unit for temperature - Answers Kelvin (K)
SI unit for amount of substance - Answers mole (mol)
Density formula - Answers density = mass ÷ volume
Meniscus - Answers Curve of liquid in container; read at bottom
Exact numbers - Answers Known with certainty (counting, definitions)
Inexact numbers - Answers Measured values with uncertainty
Accuracy - Answers Closeness to true value
Precision - Answers Closeness of repeated measurements
Significant figures - Answers Digits known with certainty plus one estimated digit
Kelvin conversion - Answers K = °C + 273.15
Fahrenheit conversion - Answers °F = (9/5 × °C) + 32
Dalton's atomic theory - Answers Matter made of atoms; atoms rearranged in reactions
Law of definite proportions - Answers Compounds contain elements in fixed ratios
Law of multiple proportions - Answers Elements combine in small whole-number ratios
J.J. Thomson - Answers Discovered the electron using cathode ray tube
Millikan - Answers Measured charge of electron (oil drop experiment)
Rutherford - Answers Discovered nucleus with gold foil experiment
Chadwick - Answers Discovered neutron
Proton - Answers Positive particle in nucleus
Neutron - Answers Neutral particle in nucleus
Electron - Answers Negative particle outside nucleus
Atomic number (Z) - Answers Number of protons
Mass number (A) - Answers Protons + neutrons
Chemistry - Answers The study of matter and the changes it undergoes
Observation - Answers Information gathered using senses
Law - Answers Describes what happens in nature
Hypothesis - Answers Tentative explanation for observations
Theory - Answers Well-tested explanation of why something happens
Macroscopic domain - Answers Observable, large-scale phenomena
Microscopic domain - Answers Atoms and molecules
Symbolic domain - Answers Chemical symbols, formulas, equations
Solid - Answers Fixed shape and volume; particles tightly packed
Liquid - Answers Fixed volume, takes shape of container
Gas - Answers Takes shape and volume of container; particles far apart
Mass - Answers Amount of matter in an object
Weight - Answers Force of gravity acting on an object
Law of Conservation of Matter - Answers Matter is neither created nor destroyed
Atom - Answers Smallest unit of an element that retains its properties
Molecule - Answers Two or more atoms bonded together
Element - Answers Pure substance made of one type of atom
Compound - Answers Substance made of two or more elements chemically bonded
Mixture - Answers Combination of substances physically mixed
Homogeneous mixture - Answers Uniform composition throughout
Heterogeneous mixture - Answers Non-uniform composition
Physical property - Answers Can be observed without changing identity
Chemical property - Answers Describes ability to undergo chemical change
Physical change - Answers Change in form but not identity
Chemical change - Answers Change that forms a new substance
Extensive property - Answers Depends on amount of matter
Intensive property - Answers Does not depend on amount
Quantitative measurement - Answers Includes numbers and units
Qualitative measurement - Answers Descriptive, no numbers
SI unit for length - Answers meter (m)
SI unit for mass - Answers kilogram (kg)
SI unit for time - Answers second (s)
SI unit for temperature - Answers Kelvin (K)
SI unit for amount of substance - Answers mole (mol)
Density formula - Answers density = mass ÷ volume
Meniscus - Answers Curve of liquid in container; read at bottom
Exact numbers - Answers Known with certainty (counting, definitions)
Inexact numbers - Answers Measured values with uncertainty
Accuracy - Answers Closeness to true value
Precision - Answers Closeness of repeated measurements
Significant figures - Answers Digits known with certainty plus one estimated digit
Kelvin conversion - Answers K = °C + 273.15
Fahrenheit conversion - Answers °F = (9/5 × °C) + 32
Dalton's atomic theory - Answers Matter made of atoms; atoms rearranged in reactions
Law of definite proportions - Answers Compounds contain elements in fixed ratios
Law of multiple proportions - Answers Elements combine in small whole-number ratios
J.J. Thomson - Answers Discovered the electron using cathode ray tube
Millikan - Answers Measured charge of electron (oil drop experiment)
Rutherford - Answers Discovered nucleus with gold foil experiment
Chadwick - Answers Discovered neutron
Proton - Answers Positive particle in nucleus
Neutron - Answers Neutral particle in nucleus
Electron - Answers Negative particle outside nucleus
Atomic number (Z) - Answers Number of protons
Mass number (A) - Answers Protons + neutrons
