AQA GCSE Chemistry equations and formulas already rated A+

AQA GCSE Chemistry equations and formulas already rated A+ 1. How do you calculate the number of neutrons in an atom? Answer: You can calculate the number of neutrons by subtracting the atomic number from the mass number. 2. What is the relationship between atomic number and number of electrons? Answer: The atomic number is equal to the number of electrons in an atom. 3. How do you calculate relative atomic mass? Answer: Relative atomic mass is calculated by summing up the product of the mass number and abundance of each isotope, then dividing by 100. 4. What is relative formula mass, and how is it used? Answer: Relative formula mass is used to calculate the total mass of a compound based on the relative atomic masses of its elements. 5. How do you calculate the number of moles of a substance? Answer: You can calculate the number of moles by dividing the mass of the substance in grams by its atomic mass (in grams per mole). 6. What is percentage yield, and how is it calculated? Answer: Percentage yield is calculated by dividing the actual mass of product produced by the maximum theoretical mass possible, then multiplying by 100. 7. What is percentage atom economy, and how is it calculated? Answer: Percentage atom economy is calculated by dividing the molecular weight of the desired product by the sum of the molecular weights of the reactants, then multiplying by 100. 8. How do you express concentration in g/dm³? Answer: Concentration can be expressed in g/dm³ by dividing the amount of solute in grams by the volume of solution in deciliters, or converting to cubic centimeters first. 9. How do you calculate the number of moles of gas? Answer: You can calculate the number of moles of gas by dividing its volume in deciliters or cubic centimeters by 24 or 24,000, respectively. 10. Write a word equation for a reaction between magnesium and copper(II) sulfate. Answer: The word equation is "magnesium + copper(II) sulfate → magnesium sulfate + copper". 11. Write a symbol equation for a reaction between magnesium and copper(II) sulfate. Answer: The symbol equation is "Mg(s) + CuSO₄(aq) → MgSO₄(aq) + Cu(s)". 12. Write an ionic equation for a reaction between magnesium and copper(II) sulfate. Answer: The ionic equation is "Mg(s) + Cu²⁺(aq) → Mg²⁺(aq) + Cu(s)". 13. Write a word equation for a reaction between zinc and lead nitrate. Answer: The word equation is "zinc + lead nitrate → zinc nitrate + lead". 14. Write a symbol equation for a reaction between zinc and lead nitrate. Answer: The symbol equation is "Zn(s) + Pb(NO₃)₂(aq) → Zn(NO₃)₂(aq) + Pb(s)". 15. Write an ionic equation for a reaction between iron and copper(II) ions. Answer: The ionic equation is "Fe(s) + Cu²⁺(aq) → Fe²⁺(aq) + Cu(s)". 16. Write half-equations for iron and copper for the displacement of copper(II) ions by iron. Answer: The half-equations are "Fe(s) → Fe²⁺(aq) + 2e⁻" for iron, and "Cu²⁺(aq) + 2e⁻ → Cu(s)" for copper. 17. What are some common ions found in solutions? Answer: Common ions include chloride (Cl⁻), sulfate (SO₄²⁻), and nitrate (NO₃⁻). 18. Write a symbol equation for a reaction between magnesium and dilute sulfuric acid. Answer: The symbol equation is "Mg(s) + H₂SO₄(aq) → MgSO₄(aq) + H₂(g)". 19. Write an ionic equation for a reaction between magnesium and dilute sulfuric acid. Answer: The ionic equation is "Mg(s) + 2H⁺(aq) → Mg²⁺(aq) + H₂(g)". 20. Write half-equations for magnesium and hydrogen for the reaction between magnesium and dilute sulfuric acid. Answer: The half-equations are "Mg(s) → Mg²⁺(aq) + 2e⁻" for magnesium, and "2H⁺(aq) + 2e⁻ → H₂(g)" for equation sulfuric acid + copper (II) oxide → copper (II) sulfate + water RP - making a copper salt symbol equation H₂SO₄ (aq) + CuO (s) → CuSO₄ (aq) +H₂O (l) ions of group 1 metals +1 ions of group 2 metals +2 aluminium ion +3 ammonium ion (NH₄) +1 ions of the transition metals size of positive charge given by the roman numeral in the name ions of group 7 non-metals -1 nitrate ions (NO₃) ⁻1 sulfate ions (SO₄) -2 metal + acid salt + hydrogen acid + base salt + water acid + alkali salt + water