Ch.1 - Intro to General ChemistrySee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

A physical change involves a change in the phases of matter, whereas a chemical change involves a change in chemical bonds. 

Understanding Mixtures

Concept #1: Homogeneous vs. Heterogeneous Mixtures

Physical & Chemical Changes

Concept #2: Physical vs. Chemical Changes

In a physical change there is a change in matter as it goes from one physical state to another. In a chemical change atoms rearrange themselves to create a new substance. 

Example #1: Which of the following represents a physical change? 

a.  Alkanes burn spontaneously.

b.  The sublimation of CO2.

c.  2 H2 (g) +  O2 (g) ----> 2 H2O (g)

d.  The rusting of a car. 

Additional Problems
If you place a glass rod over a burning candle, the glass appears to turn black. What is happening to each of the following (physical change, chemical change, both, or neither) as the candle burns? Explain each answer. a. the wax
If you place a glass rod over a burning candle, the glass appears to turn black. What is happening to each of the following (physical change, chemical change, both, or neither) as the candle burns? Explain each answer. b. the wick
If you place a glass rod over a burning candle, the glass appears to turn black. What is happening to each of the following (physical change, chemical change, both, or neither) as the candle burns? Explain each answer. c. the glass rod
Indicate whether the following is a physical or chemical change. a. Over time, liquid water in an open container evaporates and becomes a vapor in the air b. Gasoline burns in air when exposed to spark or high heat. c. After cutting a piece of sodium in air, the surface of the metal changes from a highly shiny surface to a dull gray color
Which of the following is a physical change? A. Milk sours when left out of the refrigerator B. Wood is burned on a stove C. Tums (containing CaCO3) neutralize stomach acid D. Sugar burns when heated on a skillet E. Butane in a lighter evaporates
Classify the following as physical or chemical change: a) Melting a sugar cube    b) Iron that rusts c) Burning a sugar cube d) Dissolving salt in water 
Each of the following is an example of a chemical change EXCEPT _________. A. A bicycle rusting B. Burning toast C. Chocolate melting D. Fuel combusting E. Milk souring
Which of the following is a chemical change? a. Sugar dissolves in water b. Solid CO2 is shattered with a hammer c. Ice undergoes fusion to form liquid water d. Sugar burns when heated on skillet e. Butane in a lighter evaporates.
Which of the following describes a physical change? A. Condensation forms on a windshield B. A light stick glows after shaking C. An egg solidifies during cooking D. A firecracker explodes when ignited E. Leaves turn color in the fall 
A chemical change occurs when ________. A. glucose is converted into energy within cells B. water vaporizes C. ethanol evaporates D. dew forms on a blade of grass E. salt is dissolved in water 
Based on the molecular diagram, classify each change as physical or chemical.  
Which of the following are examples of physical change? A) sugar is dissolved in water. B) coffee is brewed. C) dry ice sublimes. D) ice (solid water) melts. E) All of these are examples of physical change.
Which of the following are examples of physical change? A) dew forms on a blade of grass B) a halloween light stick glows after shaking C) an egg solidifies during cooking D) a hydrogen balloon explodes when contacted with a flame E) None of the above are physical changes.
Based on the molecular diagram, classify each change as physical or chemical.  
Which of the following are examples of a chemical change? A) Copper building materials develop a green patina over time. B) a match burns C) ethanol evaporates D) Both a and b are examples of chemical change. E) All of the above are examples of chemical change.
Based on the molecular diagram, classify each change as physical or chemical.  
Which of the following are examples of a chemical change? A) coffee brewing B) water boiling C) leaves turning color in the fall D) salt dissolves in water E) None of the above are chemical changes.
A physical change A) occurs when iron rusts. B) occurs when sugar is heated into caramel. C) occurs when glucose is converted into energy within your cells. D) occurs when sand is filtered from salt water. E) occurs when propane is burned for heat.
A chemical change A) occurs when methane gas is burned. B) occurs when paper is shredded. C) occurs when water is vaporized. D) occurs when salt is dissolved in water. E) occurs when kool-aid is stirred into water.
Circle the corresponding letter to indicate whether the following is a chemical (C) or physical (P) change.  a) Rusting of a bicycle b) Vinegar has a pungent smell c) Evaporation of water                      
Which of the following is a chemical change? A. Sugar dissolves in water B. Solid CO2 is shattered with a hammer C. Ice undergoes fusion to form liquid water D. Sugar burns when heated on skillet E. Butane in a lighter evaporates
Which of the following is a chemical change? a. oil burns on a heating element. b. water forms dew on a leaf. c. Ice undergoes fusion to form liquid water. d. Solid ice is shattered. e. Propane evaporates from a grill.  
Which of the following are examples of a chemical change? a. Copper building materials develop a green patina over time. b. a match burns c. ethanol evaporates d. Both A and B are examples of chemical change. e. All of the above are examples of chemical change.
We put a drop of water into a container and seal the container. The drop of water then vaporizes.Does the mass of the sealed container change upon vaporization?
We put a drop of water into a container and seal the container. The drop of water then vaporizes.Does its contents change upon vaporization?
The density of copper decreases as temperature increases (as does the density of most substances). Which change occurs in a sample of copper when it is warmed from room temperature to 95 oC?
A volatile liquid (one that easily evaporates) is put into a jar and the jar is then sealed.Does the mass of the sealed jar and its contents change upon the vaporization of the liquid?
Provide a corrected version for the following statement:When yellow stains in a kitchen sink are treated with bleach water, the disappearance of the stains is due to a physical change.
You may want to reference (Pages 12 - 14) Section 1.3 while completing this problem.Which of the following diagrams represents a chemical change?
A chemist mixes sodium with water and witnesses a violent reaction between the two substances. This is best classified as a(n):
You may want to reference (Page 3) Section 1.2 while completing this problem.A chemist mixes sodium with water and witnesses a violent reaction between the metal and water. This is best classified as
What is the difference between a physical change and a chemical change?
Based on the molecular diagram, classify each change as physical or chemical.
A match is lit and held under a cold piece of metal. The following observations are made: The match burns. The metal gets warmer. Water condenses on the metal. Soot (carbon) is deposited on the metal. You may want to reference(Pages 12 - 14)Section 1.3 while completing this problem.Which of these occurrences are due to physical changes, and which are due to chemical changes?
The drawing below represents two substances each undergoing a change. Indicate the state of each sample and the type of change they undergo.
Two beakers contain clear, colorless liquids. When the contents of the beakers are mixed, a white solid is formed. You may want to reference (Pages 12 - 14) Section 1.3 while completing this problem.Is this an example of a chemical or a physical change?
Classify following as physical or chemical changes.a. Moth balls gradually vaporize in a closet.
Classify following as physical or chemical changes. b. Hydrofluoric acid attacks glass, and is used to etch calibration marks on glass laboratory utensils.
Classify following as physical or chemical changes. c. A French chef making a sauce with brandy is able to burn off the alcohol from the brandy, leaving just the brandy flavoring.
Classify following as physical or chemical changes. d. Chemistry majors sometimes get holes in the cotton jeans they wear to lab because of acid spills.
You may have noticed that when water boils, you can see bubbles that rise to the surface of the water.a. What is inside these bubbles?i. airii. hydrogen and oxygen gasiii. oxygen gasiv. water vaporv. carbon dioxide gas
You may have noticed that when water boils, you can see bubbles that rise to the surface of the water.b. Is the boiling of water a chemical or physical change? Explain.
Which of the following is not a physical change?a. Metallic Sodium dulls when exposed to Air.b. Tearing of a piece of cloth.c. Sand is filtered from Sea Waterd. Dissolving sugar in a tea.
Which of the following is a chemical change?a. Metallic Sodium dulls when exposed to Air.b. Tearing of a piece of cloth.c. Sand is filtered from Sea Waterd. Dissolving sugar in a tea
What is the difference between a physical change and a chemical change? 
Which of the following are chemical changes? Check all that apply.a. water is boiledb. gasoline is evaporatedc. gasoline is burnedd. water is heated upe. water is frozen
Give four examples illustrating each of the following terms.e. physical change
Give four examples illustrating each of the following terms.f. chemical change
Which of the following will result in a chemical change? a. Burning coal in a furnace b. Drying wood in a shed c. Evaporating alcohol into vapor d. Melting ice to obtain water
Does the following diagram represent a chemical or physical change? How do you know? [Section 1.3] 
Which natural process tends to change the free nitrogen of the air into "fixed" nitrogen?a) lightning stormsb) photosynthesisc) respiration of animalsd) rusting of iron
Label each of the following as either a physical process or a chemical process: (a) corrosion of aluminum metal. 
Label each of the following as either a physical process or a chemical process:  (b) melting of ice. 
Label each of the following as either a physical process or a chemical process: (a) rusting of a metal can.
Label each of the following as either a physical process or a chemical process: (b) boiling a cup of water.
Label each of the following as either a physical process or a chemical process: (c) pulverizing an aspirin. 
Label each of the following as either a physical process or a chemical process:  (d) digesting a candy bar. 
Label each of the following as either a physical process or a chemical process: (e) exploding of nitroglyerin. 
A match is lit and held under a cold piece of metal. The following observations are made: (a) The match burns. (b) The metal gets warmer. (c) Water condenses on the metal. (d) Soot (carbon) is deposited on the metal. Which of these occurrences are due to physical changes, and which are due to chemical changes? 
Which of the following is a chemical reaction?a. solid ice water changing to liquid water.b. water molecules mixing with sugar molecules.c. liquid water changes to gaseous oxygen and hydrogen molecules.d. liquid molecules changing to gas water molecules.
Which of the following changes can be reversed by changing the temperature: (a) dew condensing on a leaf (b) an egg turning hard when it is boiled(c) ice cream melting(d) a spoonful of batter cooking on a hot griddle
Which of the following is not a physical change? a. filtering a solution b. chopping wood c. boiling water d. melting water e. none of the above
Scenes A and B depict changes in matter at the atomic scale:Which show(s) a physical change?
During a very cold winter, the temperature may remain below freezing for extended periods. However, fallen snow can still disappear, even though it cannot melt. This is possible because a solid can vaporize directly, without passing through the liquid state. Is this process (sublimation) a physical or a chemical change?
Classify each of the following changes as physical or chemical:(a) condensation of steam
The volume of a sample of oxygen gas changed from 10 mL to 11 mL as the temperature changed. Is this a chemical or physical change?
Classify each of the following changes as physical or chemical:(d) dissolving of sugar in water
Classify each of the following changes as physical or chemical:(e) melting of gold
Classify each of the following changes as physical or chemical:(b) ice melting
Classify each of the following changes as physical or chemical: (c) mixing chocolate syrup with milk
Classify each of the following changes as physical or chemical:(e) magnetizing of a screwdriver
The scenes below illustrate two different mixtures. When mixture A at 273 K is heated to 473 K, mixture B results.How many different physical changes occur?
Use the following equations to answer the next four questions:i. H2O(s) ⟶ H2O(l)ii. Na+(aq) + Cl−(aq) + Ag+(aq) + NO3−(aq) ⟶ AgCl(s) + Na+(aq) + NO3−(aq)iii. CH3OH(g) + O2(g) ⟶ CO2(g) + H2O(g)iv. 2H2O(l) ⟶ 2H2(g) + O2(g)v. H+(aq) + OH−(aq) ⟶ H2O(l)(a) Which equation describes a physical change?
What kind of change does not alter the identity of a material?a. Chemicalb. Physicalc. Physical stated. Temperature
Scenes A and B depict changes in matter at the atomic scale:Which show(s) a chemical change?
Which of the following is a chemical change? Explain your reasoning: (a) boiling canned soup(b) toasting a slice of bread(c) chopping a log(d) burning a log
Classify each of the following changes as physical or chemical:(a) coal burning
A 2.0-liter volume of hydrogen gas combined with 1.0 liter of oxygen gas to produce 2.0 liters of water vapor. Does oxygen undergo a chemical or physical change?
Classify each of the following changes as physical or chemical:(b) burning of gasoline
Classify each of the following changes as physical or chemical:(c) souring of milk
Classify each of the following changes as physical or chemical:(d) explosion of a firecracker
The scenes below illustrate two different mixtures. When mixture A at 273 K is heated to 473 K, mixture B results.How many different chemical changes occur?
Label each transition in this flowchart as a chemical change or a physical change.
Define physical property and chemical property. Identify type of property in the following statement:  • A magnet separates a mixture of black iron shavings and white sand.
Define physical change and chemical change. State which type of change occurs in the following statement: • The iron in discarded automobiles slowly forms reddish brown, crumbly rust.
Scenes A and B depict changes in matter at the atomic scale:Which result(s) in a change in state?
Classify the following as physical or chemical changes.a. Moth balls gradually vaporize in a closet.
Classify the following as physical or chemical changes.b. Hydrofluoric acid attacks glass and is used to etch calibration marks on glass laboratory utensils.
Classify the following as physical or chemical changes.c. A French chef making a sauce with brandy is able to boil off the alcohol from the brandy, leaving just the brandy flavoring.
Classify the following as physical or chemical changes.d. Chemistry majors sometimes get holes in the cotton jeans they wear to lab because of acid spills.
Which of the following are chemical changes? Which are physical changes?a. the cutting of food
Which of the following are chemical changes? Which are physical changes?b. interaction of food with saliva and digestive enzymes
Which of the following are chemical changes? Which are physical changes?c. proteins being broken down into amino acids
Which of the following are chemical changes? Which are physical changes?d. complex sugars being broken down into simple sugars
Define physical change and chemical change. State which type of change occurs in the following statement: • Passing an electric current through molten magnesium chloride yields molten magnesium and gaseous chlorine. 
Which of the following are chemical changes? Which are physical changes?e. making maple syrup by heating maple sap to remove water through evaporation
Which of the following are chemical changes? Which are physical changes?f. DNA unwinding
Which of the steps in the following process involve(s) a physical change and which involve(s) a chemical change?
Which of the following is a chemical change? 1) boiling of water 2) condensing water vapor into rainfall 3) melting wax 4) carving a piece of wood 5) broiling a steak on a grill
Which of the following is a chemical change? A. dissolving salt in water B. boiling water C. cutting a diamond D. crumpling paper E. hydrogen peroxide fizzing on a wound
Choose the chemical property. (a) Ethanol boils at 78°C. (b) The compound C2H6O has a density of 0.789 g/mL at 20°C. (c) Acetylene, C2H2, burns in air to form carbon dioxide, CO2, and water, H2O. (d) Table salt is soluble in water.
Which of these occurrences are due to physical changes, and which are due to chemical changes?