Chemistry Flashcards
What are reactants?
The substances that are present at the start of a chemical reaction.
What are products?
The substances formed by the chemical reaction.
How can chemicals be represented?
The chemicals can be represented in a word equation or a chemical equation. (Chem: H2O or word: water)
Define the law of conversation of mass?
That mass is neither created nor destroyed in chemical reactions. So the mass of any one element at the beginning of a reaction will equal the mass of that element at the end of the reaction.
Why is the law of conversation of mass important?
It shows that the total mass of chemicals is not changed in a chemical reaction.
What is a balanced equation?
A balanced equations has equal numbers of each type of atom on both sides of the equation.
Think about sodium metal reacting with water: describing observed changes:
Sodium metal reacts violently with water, undergoing a chemical change.
What is an exothermic reaction?
A chemical reaction occurring that releases energy in the form of heat/light.
What is an endothermic reaction?
A chemical reaction that absorbs energy in the form of heat.
In an exothermic reaction what type of energy is usually released?
The energy released is usually heat energy but it can also be light or electrical energy.
Where is the energy stored at in an exothermic reaction?
The reactants have a lot of energy stored in the bonds between the atoms. We the bonds break energy is released.
In an endothermic reaction why does the reaction need extra energy?
The energy produced by the breaking of the bonds in the reactants is not enough to form the products.
Where does the extra energy come from in an endothermic reaction?
The extra energy is taken from the surroundings and is used to make the high energy products.
Type of reaction: solid to liquid
Melting
Type reaction: Gas to liquid
Condensation
