chemistry part one Flashcards
What is a chemical reaction?
A process in which one or more substances (known as reactants), converted into products during the process.
What is the difference between a physical and chemical change?
Physical changes affect a substance’s appearance, no its chemical content. Chemical changes lead a substance to convert into a completely different substance with a new chemical formula.
Identify 3 signs of physical change
Expected color change, change in size or shape, change in state of matter, no new substance formed.
Identify 3 signs of chemical change.
Color change, change of temperature, evolution of a gas (formation of bubbles), precipitate (formation of a solid).
What does the arrow indicate in a chemical equation?
It is used to describe the state or progress of a reaction.
What is the Law of Conservation of Mass?
The law of conservation of mass states that in a chemical reaction mass is neither created nor destroyed.
What is a spontaneous reaction?
A chemical reaction that doesn’t need an activation energy input.
What is a non-spontaneous reaction?
A chemical reaction that requires activation energy.
What is an exothermic reaction?
Is when energy is released during a chemical reaction in the form of heat, light, and sound.
What is an endothermic reaction?
Is when energy is absorbed during a chemical reaction in the form of heat and light.
Identify 3 endothermic reactions.
Melting ice cubes, evaporating water, melting solid salts.
Identify 3 exothermic reactions.
Lighting a sparkler, fireworks, lighting a stove.
What does combustion mean?
Combustion is the scientific name for burning.
What is needed to start a combustion reaction?
Oxygen from the air.
What is photosynthesis?
Photosynthesis is the conversion of light energy into chemical energy by green plants and other organisms.
