Balance the Chemical Equation
__ K + __ MgBr --> __ KBr + __ Mg
1 K + 1 MgBr --> 1 KBr + 1 Mg
State whether the following example is a chemical or physical change: shredding paper
physical change
What is the difference between an exothermic and endothermic reaction?
An endothermic reaction absorbs energy in the form of heat from its surroundings, whereas an exothermic reaction releases energy to the surroundings.
Adding a small spoonful of sugar to a cup of tea will make it sweet. A larger spoonful will make it sweeter. This is an example of increasing __ to increase the chemical reaction.
Concentration
__ H2 + __ O2 --> __ H2O
2 H2 + 1 O2 --> 2 H2O
State whether the following example is a chemical or physical change: iron nail rusting
chemical change
Is the following chemical reaction synthesis, decomposition, replacement, or double replacement?
On heating, silver oxide yields silver and oxygen.
__ Ag2O --> __ Ag + __ O
Decomposition
___ is the minimum amount of energy needed to start a chemical reaction.
What is activation energy?
__ P + __ O2 --> __ P2O5
4 P + 5 O2 --> 2 P2O5
State whether the following example is a chemical or physical change: digestion
chemical change
Is the following chemical reaction synthesis, decomposition, replacement, or double replacement?
Sulfur reacts with oxygen to form sulfur dioxide
__ S8 + __ O2 --> __ SO3
Synthesis
When a piece of solid substance reacts with a liquid or gas, only the particles on the surface of the solid come into contact with the other reactant. If you increase the __ of the solid, you will increase the rate of the reaction.
Surface area
__ S8 + __ O2 --> __ SO3
1 S8 + 12 O2 --> 8 SO3
State whether the following example is a chemical or physical change: boiling water
physical change
Is the following chemical reaction synthesis, decomposition, replacement, or double replacement?
Carbon dioxide and water react to yield glucose and oxygen.
_ CO2+ _ H2O --> _ C6H12O6 + _ O2.
Replacement
Name 4 factors that affect rates of chemical reactions.
Factors that can affect rates of reactions include surface area, temperature, concentration, and the presence of catalysts and inhibitors.
__ CO2 + __ H2O --> __ C6H12O6 + __O2
6 CO2 + 6 H2O --> 1 C6H12O6 + 6 O2
How do chemical and physical change differ from one another?
Physical changes are those in which the shape, size, or state of the matter changes, but the substance is still essentially the same. Chemical changes are those where one or more substances are combined to produce a new substance and tend to be either irreversible changes or very difficult to revert back to the original state.
What type of chemical reaction is the following chemical equation?
AgNO3 + NaCl --> AgCl + NaNO3
Double replacement
Increasing the temperature of a chemical reaction also typically increases the reaction rate. Why?
When you heat a substance, its particles move faster. Faster-moving particles have more energy, which helps reactants get over the activation energy barrier more quickly. Also, faster-moving particles come in contact more often, giving more chances for a reaction to happen.