Exam Style Questions

• What factors affect the reaction rates of alkali metals?

  • Atomic size
  • Ionization energy
  • Reactivity
  • Electronic configuration

  
• What is the time taken for complete reaction in seconds for Lithium?

  25 seconds

  
• What is the atomic number of Lithium?

  3

  
• What is the time taken for complete reaction in seconds for Sodium?

  15 seconds

  
• What is the time taken for complete reaction in seconds for Potassium?

  5 seconds

  
• What is the atomic number of Sodium?

  11

  
• What is the atomic number of Potassium?

  19

  
• What is the atomic number of Rubidium?

  37

  
• How does atomic number influence the time taken for complete reaction of alkali metals?

  • As atomic number increases, the time taken for complete reaction decreases
  • This is due to increased reactivity and lower ionization energy with higher atomic number

  
• What is the time taken for complete reaction in seconds for Rubidium?

  3 seconds

  
• What is the balanced chemical equation for the reaction between sodium carbonate and nitric acid?

  $Na_2CO_3(s) +$$2HNO_3(aq) → 2NaNO_3(aq) +$$H_2O(l) +$$CO_2(g)$
• What type of chemical reaction is represented by the equation $Na_2CO_3(s) +$$2HNO_3(aq) → 2NaNO_3(aq) +$$H_2O(l) +$$CO_2(g)?$


  • Neutralisation reaction
• What salt is produced in the reaction $Na_2CO_3(s) +$$2HNO_3(aq) → 2NaNO_3(aq) +$$H_2O(l) +$$CO_2(g)?$


  NaNO₃
• What is the role of Na₂CO₃ in the reaction $Na_2CO_3(s) +$$2HNO_3(aq) → 2NaNO_3(aq) +$$H_2O(l) +$$CO_2(g)?$


  Base
• What decomposition reaction involves hydrogen peroxide?

  • The decomposition of hydrogen peroxide into water and oxygen
• Over what period was the concentration of H₂O₂ measured during its decomposition in the experiment?

  15 minutes
• What was the concentration of H₂O₂ in mol/l after 10 minutes?

  0.25 mol/l
• How do you calculate the average rate of a reaction?

  Divide the change in concentration by the change in time
• What effect does the addition of manganese dioxide as a catalyst have on the rate of decomposition of hydrogen peroxide?

  It increases the rate
• What is the atomic number of an atom with 15 protons?

  15
• How many protons and neutrons are present in the given atom with atomic number 15?

  15 protons and 16 neutrons
• What is the mass number of an atom with 15 protons and 16 neutrons?

  31
• What element has atomic number 15?

  Phosphorus or P
• What distinguishes the two main isotopes of chlorine?

  • They have a different number of neutrons
• How does a chlorine ion gaining one electron change its overall charge?

  The chlorine atom gains a negative charge
• What is the electron configuration of the given element?

  • 2.8.8.1
• To which group does the element with electron configuration 2.8.8.1 belong?


  1
• Which period does the element with electron configuration 2.8.8.1 belong to?

  4
• What type of bonds are present in methane (CH₄)?

  • Covalent bonds
• How many covalent bonds are in a single methane molecule?

  4
• What is meant by a covalent bond?

  Two atoms share 2 electrons to achieve a stable electron arrangement, usually a full outer shell
• What is the relationship between a metal's atomic number and the time it takes to react completely with hydrochloric acid?

  The higher the atomic number, the faster the reaction
• How does atomic number affect the reaction rate of metals with hydrochloric acid?

  Higher atomic number leads to faster reaction rate
• What bonding and structure are likely present in a compound with a high melting point, high boiling point, conducts electricity when molten but not solid?

  • Ionic bonding and structure
• What type of bonding and structure is likely present in a compound with the described properties?

  Ionic
• What would be the state of an ionic compound at 900°C?

  Liquid
• Write the chemical formula for potassium nitrate

  $KNO_3$
• Calculate the concentration of potassium nitrate solution given that 250 $cm^3$ contains 0.5 moles.


  2 mol/l
• Name a common sunscreen ingredient.

  Zinc oxide, ZnO
• What is the gram formula mass of zinc oxide, ZnO?

  81g