Chemical Reactions and Their Properties

This video covers the basics of chemical reactions and equations, including evidence of reactions, balancing equations, and the law of conservation of mass. It explains how to identify reactants and products, the role of coefficients and subscripts, and the factors affecting reaction rates. The video also discusses endothermic and exothermic reactions, providing examples and practice problems to reinforce learning.

What is a chemical reaction a result of?

• A physical change

• A temperature change

• A color change

• A chemical change

In a chemical equation, what does the arrow represent?

• Yields or produces

• A solid formation

• A reversible reaction

• A gas formation

What state is lead(II) iodide in the practice problem?

• Aqueous

• Gas

• Liquid

• Solid

What is the coefficient for potassium nitrate in the practice problem?

• 1

• 3

• 2

• 4

According to the law of conservation of mass, what must be true in a chemical reaction?

• The mass of reactants is less than the mass of products

• The mass of reactants is greater than the mass of products

• The mass of reactants equals the mass of products

• The mass of reactants is unrelated to the mass of products

Which factor does NOT increase the rate of a chemical reaction?

• Increasing surface area

• Adding a catalyst

• Decreasing concentration

• Increasing temperature

What is the role of a catalyst in a chemical reaction?

• It speeds up the reaction without being consumed

• It changes the products of the reaction

• It participates in the reaction

• It slows down the reaction

What type of reaction absorbs energy and feels cold?

• Neutralization

• Combustion

• Endothermic

• Exothermic

Which of the following is an example of an exothermic reaction?

• Photosynthesis

• Burning

• Sublimation

• Melting

When balancing chemical equations, what should you never change?

• The number of molecules

• The state of matter

• Subscripts

• Coefficients