Exam Guide

Exam guide

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Chemical Reactions

1. A chemical reaction is a process that leads to the transformation of one set of chemical substances to another.
2. Reactants are the starting materials involved in a chemical reaction.
3. Products are the substances formed after a chemical reaction has taken place.
4. Chemical reactions can be represented by chemical equations, which show the reactants and products of the reaction.
5. The law of conservation of mass states that the total mass of the reactants must be equal to the total mass of the products.

Types of Chemical Reactions

1. The four types of chemical reactions are:
1. Combination reactions, in which two or more substances combine to form a single, more complex substance. For example, 2H2 + O2 → 2H2O
2. Decomposition reactions, in which a single, more complex substance breaks down into two or more simpler substances. For example, 2H2O → 2H2 + O2
3. Displacement reactions, in which one element replaces another element in a compound. For example, Zn + CuSO4 → Cu + ZnSO4
4. Double displacement reactions, in which the cations and anions of two different compounds switch places, forming two new compounds. For example, AgNO3 + NaCl → AgCl + NaNO3.
2. Chemical reactions can be classified based on the type of reaction that occurs.

Redox Reactions

1. A redox reaction is a chemical reaction in which one species is oxidized (loses electrons) and another is reduced (gains electrons).
2. Oxidation occurs when an atom loses electrons in a redox reaction.
3. Reduction occurs when an atom gains electrons in a redox reaction.
4. Redox reactions can occur in both acidic and basic environments.
5. One way to recognize a redox reaction is to look for changes in oxidation states of the reactants and products.

Importance and How to Balance Chemical Equations

1. Balancing chemical equations is important because it ensures that the law of conservation of mass is followed in the reaction, which states that the total mass of the reactants must be equal to the total mass of the products.
2. To balance a chemical equation, you need to make sure that there are equal numbers of atoms on both sides of the equation.
3. You can balance an equation by adjusting the coefficients in front of each molecule or compound.

Antoine Lavoisier

1. Born in 1743 in Paris, France, Antoine Lavoisier is considered the "Father of Modern Chemistry" because of his many contributions to the field.
2. Lavoisier is best known for his development of the law of conservation of mass, which states that the total mass of the reactants must be equal to the total mass of the products.
3. He also recognized the role of oxygen in combustion and developed the first modern system of chemical nomenclature.

Thermal Expansion and Calorie

1. Thermal expansion is the tendency of matter to change in volume or shape due to a change in temperature.
2. Linear expansion is a type of thermal expansion in which an object increases in length as it heats up.
3. Volume expansion is a type of thermal expansion in which an object increases in volume as it heats up.
4. A calorie is a unit of measurement for energy, and is defined as the amount of heat required to raise the temperature of one gram of water by one degree Celsius.

Temperature conversions

1. Celsius to Kelvin:
2. K = C + 273.15
3. Fahrenheit to Kelvin:
4. K = (F − 32) × 5/9 + 273.15
5. Fahrenheit to Celsius:
6. C = (F - 32) * 5/9
7. Kelvin to Celsius:
8. C = K - 273.15
9. Kelvin to Fahrenheit:
10. F = (K − 273.15) × 9/5 + 32
11. Celcius to Fahrenheit
12. F = (C × 9/5) + 32