States of Matter
Which state of matter has particles that vibrate in fixed positions but do not flow?
Solid
Why is distilled water classified as a pure substance rather than a mixture?
It has a fixed composition and uniform properties
Why is density considered a characteristic property of matter?
It does not depend on sample size
Why is dissolving sugar in water a physical change even though it looks different?
No new substance is formed
What major idea did Dalton contribute to atomic theory that is still accepted today?
Matter is composed of atoms
Why does a liquid have a definite volume but no definite shape?
Particles are close together but can slide past one another
How is a compound different from an element at the atomic level?
Compounds contain two or more elements chemically bonded
Which property best distinguishes aluminum from iron mass volume or density?
Density
Which observation best indicates a chemical change melting color change or shape change?
Color change
How did the discovery of the electron change Daltons atomic model?
Atoms were shown to be divisible
Why do gases expand to fill the entire volume of a container?
Gas particles move freely and are far apart
Why is air considered a homogeneous mixture even though it contains multiple gases?
Its composition is uniform throughout
Why is conductivity classified as a physical property?
It can be observed without changing the substance
Why is rusting irreversible under normal conditions?
A new substance is formed
Why did Rutherfords gold foil experiment disprove the plum pudding model?
It showed atoms have a dense nucleus
During which phase change do particles lose kinetic energy condensation or evaporation?
Condensation
Which classification best describes soil and why?
Heterogeneous mixture because it has visibly different components
If two objects have the same mass but different volumes what property must be different?
Density
Cutting paper and burning paper produce different results What is the key difference?
Burning forms new substances while cutting does not
What evidence led scientists to conclude electrons occupy energy levels?
Atomic emission spectra
A substance melts at a constant temperature What does this indicate about the substance?
It is a pure substance
Why can mixtures be separated by physical means but compounds cannot?
Mixtures are not chemically bonded
Why is flammability classified as a chemical property?
It describes how a substance reacts chemically
Which type of change always involves breaking or forming chemical bonds?
Chemical change
Why was the discovery of the neutron important to atomic theory?
It explained atomic mass without affecting charge