FREE CART Chemical Reactions Questions and Answers

Question 1

Which of the following is a balanced equation for the combustion of methane (CH₄)?

Accepted Answer

CH₄ + 2O₂ → CO₂ + 2H₂O

Answer

To balance the combustion of methane (CH₄), the number of atoms for each element must be equal on both sides of the equation. One carbon atom on the left requires one CO₂ on the right. Four hydrogen atoms on the left require two H₂O on the right (2*2=4). This then results in four oxygen atoms on the right (2 from CO₂ + 2 from 2H₂O), which means two O₂ molecules are needed on the left (2*2=4).

Question 2

What type of reaction is represented by the equation: 2H₂ + O₂ → 2H₂O?

Accepted Answer

Synthesis reaction

Answer

A synthesis reaction, also known as a combination reaction, is characterized by two or more simple reactants combining to form a more complex product. In the given equation, hydrogen and oxygen gases combine to form water, fitting this definition perfectly.

Question 3

In a chemical reaction, the substances that are present at the beginning and undergo change are called:

Accepted Answer

Reactants

Answer

In a chemical reaction, the substances that are present at the beginning and undergo a chemical change are called reactants. These starting materials are consumed during the reaction to form new substances, which are known as products.

Question 4

Which of the following represents a double displacement reaction?

Accepted Answer

AB + CD → AD + CB

Answer

A double displacement reaction involves the exchange of ions between two compounds, typically in an aqueous solution. The cations of the two reactants effectively switch places to form two new compounds, following the general form AB + CD → AD + CB.

Question 5

What is the law that states that mass is neither created nor destroyed in a chemical reaction?

Accepted Answer

Law of Conservation of Mass

Answer

The Law of Conservation of Mass states that in any closed system, mass is neither created nor destroyed during a chemical reaction. This fundamental law means that the total mass of the reactants must equal the total mass of the products.

CART - Chemistry Acceleration Readiness Test Practice Test

CART - Chemistry Acceleration Readiness Test Practice Test

FREE CART Chemical Reactions Questions and Answers