What are the main formulas in junior high school chemistry?

1. What are the main formulas in junior high school chemistry?

Junior high school chemistry mainly involves some basic chemical formulas, including but not limited to:

1. Molar mass calculation formula:

   • Molar mass (M) = relative molecular mass (Mr) / relative molecular weight (n)

2. Calculation formula of molar concentration:

   • Molar concentration (C) = Number of moles of substance (n) / Volume of solution (V)

3. Gas The calculation formula for molar volume (ideal gas law):

   • PV = nRT

4. Electricity calculation formula:

   • Electricity (Q) = Current (I) × Time (t)

5. Mass conservation formula:

   • The mass of the substance before the reaction = the mass of the substance after the reaction

2. Chemical formulas that are commonly used in junior high schools?

In junior high school chemistry, the following are some very commonly used chemical formulas:

1. Ionization equilibrium of water:

   • H₂O ⇌ H⁺ OH⁻

2. Acid-base neutralization reaction:

   • H⁺ OH ⁻ → H₂O

3. Redox reaction:

   • Fe²⁺ Cl₂ → Fe³⁺ 2Cl⁻

4. The calculation formula of ionization degree:

   • Ionization degree (α) = actual ionization number/theoretical ionization number × 100%

5. The difference between molecular formula and ionic formula:

   • Molecular formula represents the type and number of atoms in the molecule, such as H₂O; ionic formula represents The type and number of ions in the ion, such as Na⁺ Cl⁻

3. What are the chemical calculation formulas?

In chemical calculations, the following are some commonly used calculation formulas:

1. Calculation of moles of a substance:

   • Number of moles (n) = mass (m) / relative molecular mass (Mr)

2. Calculation of solution concentration:

   • Molar concentration (C) = number of moles (n) / solution volume (V)

3. Mass conservation calculation:

   • The mass of the substance before the reaction = the mass of the substance after the reaction

4. Ideal gas law calculation:

   • PV = nRT

5. Power calculation:

   • Power (Q) = Current (I) × time (t)

Summary:

1. (1) The main formulas involved in junior high school chemistry include molar mass , molar concentration, ideal gas law, etc., as well as commonly used reaction formulas such as water ionization equilibrium, acid-base neutralization, oxidation-reduction, etc.

2. (2) Very commonly used chemical formulas include the ionization equilibrium of water, acid-base neutralization reactions, redox reactions, etc. These are often encountered in junior high school chemistry learning.

3. (3) Commonly used formulas in chemical calculations include calculation of moles of substance, solution concentration calculation, mass conservation calculation, ideal gas law calculation, electricity calculation, etc. These formulas can be used to calculate Various chemical calculations.

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