Task 3 Science

• What is a physical change?


  A physical change involves a reversible change in state without breaking bonds between atoms.
• How do physical changes typically occur?

  They usually involve a change in state with energy added or removed.
• What happens to the bonds between atoms during a physical change?

  The bonds do not break between the atoms.
• What changes occur in a physical change?

  The arrangement of atoms in space changes.
• What characterizes a chemical change?

  A chemical change involves breaking bonds and/or forming new bonds between atoms.
• What is produced as a result of a chemical change?

  New substances or chemicals are formed.
• Are chemical changes usually reversible or irreversible?

  Chemical changes are usually irreversible.
• What are some indicators of a chemical change?

  Indicators include unexpected color changes, spontaneous temperature changes, bubbles appearing, and flames or light being produced.
• What is the worded equation for the reaction between magnesium and hydrochloric acid?

  Magnesium + Hydrochloric acid → Magnesium chloride + Hydrogen.
• What is the product of the reaction between magnesium and oxygen?

  Magnesium oxide.
• What defines acids in terms of ion release?

  Acids are proton donors as they release hydrogen (H+) ions into an aqueous solution.
• What are some properties of acids?

  Acids have a sour taste, are corrosive, conduct electricity, and react with some metals to produce hydrogen gas and salt.
• How does the strength of an acid relate to hydrogen ion release?

  The strength of an acid depends on how many hydrogen ions are released; more H+ ions indicate a stronger acid.
• Name a strong acid.

  Hydrochloric acid (HCl).
• Name a weak acid.

  Sulfurous acid (H2SO3).
• What defines bases in terms of ion release?

  Bases are proton receivers as they release hydroxide (OH-) ions.
• What are some properties of bases?

  Bases are caustic, have a slimy/soapy feeling, a bitter taste, and are neutralized by acids.
• How does the strength of a base relate to hydroxide ion release?

  The strength of a base depends on how many hydroxide ions are released; more OH- ions indicate a stronger base.
• Name a strong base.

  Sodium hydroxide (NaOH).
• Name a weak base.

  Ammonia (NH3).
• What does pH measure?

  pH measures how acidic or basic a solution is.
• What is the pH range for acidic solutions?

  pH less than 7.
• What is the pH of a neutral solution?

  pH 7.
• What is the pH range for basic solutions?

  pH more than 7.
• What is the general equation for acid-base neutralization?

  ACID + BASE → SALT + WATER.
• What is produced in the reaction between an acid and a carbonate?

  Salt, water, and carbon dioxide are produced.
• What is the equation for the reaction of sulfuric acid with copper carbonate?

  Sulfuric Acid + Copper Carbonate → Copper Sulfate + Water + Carbon Dioxide.
• What is the general equation for the reaction of acids with metals?

  ACID + METAL → SALT + HYDROGEN GAS.
• What is the equation for the reaction of hydrochloric acid with magnesium?

  Hydrochloric acid + Magnesium → Magnesium Chloride + Hydrogen Gas.
• What characterizes exothermic reactions?

  Exothermic reactions transfer energy to the surroundings, usually as heat, causing the surroundings to become hotter.
• What characterizes endothermic reactions?

  Endothermic reactions absorb energy, usually as heat, causing the surroundings to become colder.
• What is metabolism?


  Metabolism is the sum of all biochemical reactions in an organism, including both exothermic and endothermic reactions.
• What is the significance of the periodic table in chemistry?

  The periodic table organizes elements based on their atomic number, which is the number of protons and electrons.
• How do you calculate the number of neutrons in an atom?

  Neutrons = Mass number - Atomic number.
• What does the law of conservation state regarding chemical reactions?

  The law of conservation states that mass is not created or destroyed during a chemical reaction.
• How are metals and non-metals categorized in the periodic table?

  Metals are typically found on the left side and non-metals on the right side of the periodic table.
• Give an example of an exothermic reaction.

  Condensation of water vapor into rain releasing energy in the form of heat.
• Give an example of an endothermic reaction.

  Photosynthesis.
• What are biochemical reactions?

  Biochemical reactions are chemical reactions that take place inside living things.
• What is the role of protons and electrons in determining atomic number?

  The atomic number is determined by the number of protons and electrons in an atom.