States of Matter & Particle Theory
True/False
Particles in a solid move freely and rapidly.
False
In solids, particles are tightly packed and vibrate in fixed positions. They do not move freely like in gases.
True/False
A compound can be separated by physical means.
False
Compounds are chemically bonded substances and require chemical reactions to separate. Physical methods only work for mixtures.
True/False
Melting ice is a chemical change.
False
Melting is a physical change — the substance remains water (H₂O), only the state changes.
True/False
A conical flask is ideal for heating liquids evenly.
False
Conical flasks are good for mixing and swirling, but round-bottom flasks are better for even heating.
True/False
All acids taste bitter and feel slippery.
False
Acids typically taste sour, while bases feel slippery and taste bitter.
MCQ
Which state of matter has no fixed shape but a fixed volume?
A. Solid
B. Liquid
C. Gas
D. Plasma
B. Liquid
Liquids take the shape of their container but maintain a fixed volume due to moderate particle attraction.
True/False
All mixtures are heterogeneous.
False
Mixtures can be homogeneous (uniform, like salt water) or heterogeneous (non-uniform, like sand in water).
Fill in the Blanks
A change that can be easily reversed is usually a ___ change.
A. physical
B. chemical
C. permanent
D. explosive
A. physical
Physical changes like freezing or melting are often reversible, unlike chemical changes.
MCQ
Which apparatus is best for measuring exact volumes of liquid?
A. Beaker
B. Measuring cylinder
C. Pipette
D. Test tube
C. Pipette
A pipette delivers precise volumes, unlike beakers or test tubes which are for general use.
MCQ
Which of the following is a household base?
A. Vinegar
B. Lemon juice
C. Baking soda
D. Orange juice
C. Baking soda
Baking soda (sodium bicarbonate) is a mild base used in cooking and cleaning.
MCQ
Which change of state involves particles gaining energy and moving further apart?
A. Freezing
B. Condensation
C. Melting
D. Boiling
D. Boiling
Boiling adds energy, causing particles to overcome attraction and move apart into the gas phase.
Fill in the Blanks
A ___ has a fixed composition and properties, while a mixture does not.
A. compound
B. solution
C. element
D. suspension
A. compound
A compound has a definite ratio of elements and consistent properties. Mixtures vary depending on their components.
MCQ
Which of the following is a physical change?
A. Burning paper
B. Cooking an egg
C. Melting wax
D. Rusting steel
C. Melting wax
Melting wax changes its state, not its chemical composition — it’s a physical change.
Fill in the Blanks
A ___ is used to support a beaker over a Bunsen burner.
A. tripod
B. funnel
C. spatula
D. burette
A. tripod
A tripod holds a wire gauze and supports containers during heating.
Fill in the Blanks
A substance with a pH of 2 is considered a ___ acid.
A. strong
B. weak
C. neutral
D. basic
A.strong
A pH of 2 indicates a strong acid, as lower pH values mean higher acidity.
Fill in the Blanks
The movement of particles from an area of high concentration to low concentration is called ___.
A. diffusion
B. convection
C. conduction
D. radiation
A.diffusion
Diffusion is the passive spreading of particles, seen in gases and liquids.
MCQ
Which of the following is a mixture?
A. Water
B. Sodium chloride
C. Air
D. Carbon dioxide
C. Air
Air is a mixture of gases (oxygen, nitrogen, COâ‚‚, etc.) that are not chemically bonded.
Fill in the Blanks
The formation of bubbles during a reaction often indicates a ___ change.
A. chemical
B. physical
C. thermal
D. nuclear
A. chemical
Gas production (bubbles) is a common sign of a chemical reaction, such as acid reacting with metal.
MCQ
Which method best separates a dye mixture in ink?
A. Filtration
B. Chromatography
C. Evaporation
D. Decanting
B. Chromatography
Chromatography separates components based on solubility and movement through paper.
Fill in the Blanks
Litmus paper turns ___ in acidic solutions.
A. red
B. blue
C. green
D. purple
A. red
Red litmus indicates an acidic environment; blue litmus turns red in acid.
MCQ
Which state of matter has the weakest forces between particles?
A. Solid
B. Liquid
C. Gas
D. Plasma
C. Gas
Gases have the weakest intermolecular forces, allowing particles to move freely and occupy any volume.
MCQ
Brass is a mixture of copper and zinc. What type of mixture is it?
A. Suspension
B. Solution
C. Alloy
D. Compound
C. Alloy
Brass is an alloy — a homogeneous mixture of metals with no chemical bonding between them.
True/False
Evaporation involves a change in chemical composition.
False
Evaporation is a physical change — the substance remains the same, only its state changes.
Fill in the Blanks
The ___ flame of a Bunsen burner is used for maximum heating.
A. blue
B. yellow
C. orange
D. red
A. blue
The blue flame (air hole open) is hotter and cleaner than the yellow safety flame.
MCQ
Which of the following has a pH closest to neutral?
A. Vinegar
B. Soap
C. Distilled water
D. Lemon juice
C. Distilled water
Distilled water has a pH of 7, which is neutral.