Physical or Chemical 1
Lighting a match to start a fire. Physical or Chemical Change?
Chemical Change. (Combustion creates entirely new substances like ash, smoke, and gases)
Melting a scoop of ice cream on a warm sidewalk is a physical change because the chemical makeup of the ingredients remains unchanged. True or False?
True, (It only changes state from solid to liquid; the ingredients don't change).
Freezing liquid water into ice cubes changes the chemical identity of the water molecules into a new solid compound... True or False?
False (Freezing is a physical change of state; both ice and water are (H20).
Water evaporating from a puddle on a sunny afternoon is a physical change... True or False?
True (Evaporation is just a phase change from liquid to gas; the molecules stay (H2O).
Mixing vinegar and baking soda to make bubbling foam. Physical or Chemical Change?
Chemical change (An acid-base reaction produces a brand-new substance: carbon dioxide gas).
Dissolving table salt in water breaks the sodium and chlorine atoms down into entirely new elements... True or False?
False, (Dissolving is physical; it separates the salt ions into solution, but doesn't change the elements).
Dropping and shattering a glass cup on the kitchen floor is an example of what type of change? Physical or Chemical change?
Physical change (The shape and size changed, but every broken shard is still chemically glass).
Frying an egg in a hot skillet causes irreversible chemical changes where heat denatures and cross-links the egg proteins... True or False?
True (The liquid proteins permanently change into a new solid structure that cannot be un-cooked).
Baking a birthday cake in an oven involves which type of change? Physical or Chemical change?
Chemical change (Heat permanently changes the molecular structure of the proteins, flour, and eggs).
Chopping a large log into small pieces of firewood using an axe is classified as which type of change? Physical or Chemical change?
Physical change (It only alters the size and shape of the wood, not its molecular makeup).
Photosynthesis in plants, which converts carbon dioxide and water into glucose and oxygen, is a chemical change... True or False?
True (It breaks and reforms bonds to create completely new chemical substances).
Boiling water on a stove creates steam, which is a completely new chemical substance (H3O). True or False?
False, (Steam is still water vapor; its chemical formula is still H2O).
The digestion of food in the human body is a chemical change... True or False?
True (Stomach acids and enzymes chemically break down large macromolecules into simple nutrients).
Lighting a match to start a fire is best classified as which type of change? Physical or Chemical change
Chemical change (Combustion permanently turns the match head into ash, smoke, and gases).
A car body developing orange-brown rust over the winter is an example of what kind of change?
Chemical change (Iron reacts with oxygen and water to form a brand-new compound: iron oxide).
Mixing vinegar and baking soda to create a bubbling, fizzing foam represents which type of change? Physical or Chemical change?
Chemical change (An acid-base reaction occurs that creates a brand-new substance: carbon dioxide gas).
Mechanically chewing a bite of food with your teeth is an example of a chemical change... True or False?
False (Chewing is a physical change that breaks food into smaller pieces; chemical digestion happens later).