What is a chemical reaction?

• A chemical reaction is a process that transforms reactants into products through the breaking and forming of chemical bonds.

• A chemical reaction is a process that only involves physical changes.

• A chemical reaction is a method to separate elements from a compound.

• A chemical reaction is the mixing of substances without any change.

Define the law of conservation of mass.

• Mass is only conserved in open systems.

• Mass is conserved in a closed system; it cannot be created or destroyed.

• Mass changes form but is not conserved.

• Mass can be created but not destroyed.

What are reactants and products in a chemical reaction?

• Reactants are the starting materials; products are the substances formed.

• Reactants are the substances that disappear; products are the substances that remain unchanged.

• Reactants are the final products; products are the initial materials.

• Reactants are always gases; products are always solids.

Explain the difference between exothermic and endothermic reactions.

• Exothermic reactions release energy; endothermic reactions absorb energy.

• Both exothermic and endothermic reactions release energy.

• Exothermic reactions absorb energy; endothermic reactions release energy.

• Exothermic reactions occur only in gases; endothermic reactions occur only in liquids.

What is pH and how is it measured?

• pH is a measure of temperature, measured with thermometers.

• pH indicates the concentration of oxygen in water, measured with oxygen sensors.

• pH is a measure of pressure, measured with barometers.

• pH is a measure of acidity/alkalinity, measured with pH meters or indicator strips.

List three properties of acids.

• Bitter taste

• Do not conduct electricity

• React with metals to form hydrogen gas

• 1. Sour taste 2. Conduct electricity in solution 3. React with bases to form salts and water

What is the neutralization reaction?

• A reaction between an acid and a base that produces water and a salt.

• A reaction between a base and a metal that produces hydrogen gas.

• A reaction that occurs only in the presence of a catalyst.

• A reaction between two acids that produces carbon dioxide.

How do bases differ from acids in terms of taste and feel?

• Acids taste sweet and feel smooth; bases taste salty and feel rough.

• Acids taste spicy and feel warm; bases taste tangy and feel cool.

• Acids taste sour and feel tingling; bases taste bitter and feel slippery.

• Acids taste bland and feel dry; bases taste sour and feel sticky.

What is the role of indicators in determining acidity or basicity?

• Indicators provide a numerical value for pH levels.

• Indicators help determine acidity or basicity by changing color in response to pH levels.

• Indicators are used to neutralize acids and bases.

• Indicators measure temperature to determine acidity.

Give an example of a common acid and its use in daily life.

• Hydrochloric acid is used in swimming pool maintenance.

• Sulfuric acid is commonly used in car batteries.

• Acetic acid (vinegar) is used in cooking and food preservation.

• Citric acid (lemon juice) is used for cleaning windows.