Chemical Change Basics
A change that alters the form of a substance but does not create a new substance (e.g., cutting wood or melting ice).
What is a physical change?
The substances you start with in a chemical equation.
What are the reactants?
The minimum amount of energy needed to get a chemical reaction started.
What is activation energy?
A reaction where two or more simple substances combine to form a more complex substance, like A + B --> AB
What is a synthesis reaction?
The name of the process used to make an equation obey the Law of Conservation of Mass.
What is balancing the equation?
The formation of a gas (bubbles) or a change in temperature are often signs of this type of change.
What is a chemical change (or chemical reaction)?
The substances that are produced or formed at the end of a chemical reaction.
What are the products?
Breaking a large solid into smaller pieces increases this, which speeds up a reaction.
What is surface area?
A reaction where a complex compound breaks down into two or more simpler substances, like AB --> A + B
What is a decomposition reaction?
In the unbalanced equation H2 + O2 --> H2O, the number of oxygen atoms on the reactant side is this.
What is two?
A solid that forms and separates from a liquid mixture during a chemical reaction.
What is a precipitate?
This principle states that the total mass of the reactants must equal the total mass of the products.
What is the Law of Conservation of Mass?
A substance that speeds up a chemical reaction but is not itself changed or used up in the reaction.
What is a catalyst?
A type of replacement reaction where one element swaps places with another element in a compound.
What is a single replacement reaction?
The coefficient 2 in front of H2O means there are this many total Hydrogen atoms in the product.
What is four (4)?
A chemical reaction that releases energy, making the surroundings feel warmer, like burning wood.
What is an exothermic reaction?
A number placed in front of a chemical formula to ensure the number of atoms for each element is equal on both sides of the arrow.
What is a coefficient?
Increasing the amount of solute dissolved in a solvent increases this property, leading to faster reaction rates.
What is concentration?
In the reaction Mg + 2HCl --> MgCl2 + H2 the products are MgCl2 and this gas.
What is hydrogen gas (H2)?
The two elements involved in the single replacement reaction Al+CuO --> Al2O3 + Cu
What are Aluminum (Al) and Copper (Cu)
A chemical reaction that absorbs energy, causing the temperature of the surroundings to drop.
What is an endothermic reaction?
If the total mass of the products is 90 grams, this was the total mass of the reactants, according to the Law of Conservation of Mass.
What is 90 grams?
A substance, like a food preservative, that slows down or prevents unwanted chemical reactions.
What is an inhibitor?
A reaction where the elements of two different compounds swap places to form two entirely new compounds.
What is a double replacement reaction?
The type of reaction in which a fuel, like methane (CH4), combines with oxygen to produce carbon dioxide and water.
What is a combustion reaction?