Balancing chemical equation

What is a chemical symbol?

• A. A letter representing an element

• B. A number indicating the mass of an element

• D. A sign for chemical reactions

• C. A symbol used in algebraic equations

Answer explanation

A chemical symbol is a letter representing an element, making choice A the correct answer.

What are reactants and products in a chemical reaction?

• C. Reactants are solid, and products are liquid

• D. Reactants are liquid, and products are gas

• B. Reactants are the starting materials, and products are the end results

• A. Reactants are the end results, and products are the starting materials

Answer explanation

Reactants are the starting materials that undergo a chemical reaction, while products are the end results of that reaction. Therefore, choice B is correct.

Why is it important to have the same number of atoms of each element on both sides of a chemical equation?

• D. To show different elements react differently

• C. To confuse students

• B. To follow the Law of Conservation of Mass

• A. To make the equation look balanced

Answer explanation

To follow the Law of Conservation of Mass

What gas is produced during the reaction between zinc and hydrochloric acid?

• A. Oxygen

• B. Nitrogen

• C. Hydrogen

• D. Carbon dioxide

Answer explanation

During the reaction between zinc and hydrochloric acid, hydrogen gas is produced as a product.

How can you test for the presence of hydrogen gas?

• A. Using a litmus paper

• B. Using a thermometer

• C. Using a burning splint

• D. Using a magnet

Answer explanation

To test for the presence of hydrogen gas, you can use a burning splint. If the gas is present, it will produce a 'pop' sound when ignited.

What strategies did you use to balance the equations in the simulation?

• C. Ignoring the unbalanced equation

• D. Using a calculator

• A. Guessing randomly

• B. Adding coefficients to balance atoms

Answer explanation

Adding coefficients to balance atoms is the correct strategy to balance equations in the simulation.

How does changing the coefficients affect the balance of the equation?

• D. It has no effect on the equation

• A. It makes the equation longer

• C. It affects the number of atoms on each side

• B. It changes the elements involved

Answer explanation

Changing the coefficients affects the number of atoms on each side of the equation, ensuring mass balance.

What did you observe during the live demonstration of the reaction between zinc and hydrochloric acid?

• D. A temperature increase

• A. A color change

• B. A sound

• C. A gas release

Answer explanation

During the live demonstration of the reaction between zinc and hydrochloric acid, a gas release was observed, making option C the correct choice.

What gas was produced during the reaction between magnesium and oxygen?

• B. Hydrogen

• A. Nitrogen

• D. Carbon dioxide

• C. Oxygen

Answer explanation

During the reaction between magnesium and oxygen, oxygen gas was produced as a product, making option C the correct choice.

What is the balanced equation for the reaction between sodium hydroxide and sulfuric acid?

• D. NaOH + H2SO4 -> Na2SO4 + H2

• C. NaOH + H2SO4 -> Na2SO4 + HO

• B. NaOH + H2SO4 -> NaSO4 + H2O

• A. 2NaOH + H2SO4 -> Na2SO4 +2 H2O

Answer explanation

Choose the answer that correctly balances the equation, which is A. 2NaOH + H2SO4 -> Na2SO4 + 2H2O