Chemical Equations

Chemistry ⇒ Chemical Reactions and Equations

Chemical Equations starts at 7 and continues till grade 12. QuestionsToday has an evolving set of questions to continuously challenge students so that their knowledge grows in Chemical Equations. How you perform is determined by your score and the time you take. When you play a quiz, your answers are evaluated in concept instead of actual words and definitions used.

See sample questions for grade 9

A chemical equation must be balanced to obey which law?

Balance the following equation: Al + O_2 \rightarrow Al_2O_3

Balance the following equation: Fe + O_2 \rightarrow Fe_2O_3

Explain why it is necessary to balance a chemical equation.

In the equation: 2KClO_3 \rightarrow 2KCl + 3O_2, how many molecules of oxygen are produced when 2 moles of potassium chlorate decompose?

In the equation: CaCO_3 \rightarrow CaO + CO_2, what type of reaction is represented?

State the difference between a skeletal and a balanced chemical equation.

State the law that is followed when balancing a chemical equation.

What does the symbol (aq) represent in a chemical equation?

What does the symbol (s) indicate in a chemical equation?

What is the coefficient of O_2 when the equation C_2H_6 + O_2 \rightarrow CO_2 + H_2O is balanced?

What is the sum of the coefficients when the equation C_3H_8 + O_2 \rightarrow CO_2 + H_2O is balanced?

Write the balanced chemical equation for the reaction of calcium with water.

Write the balanced chemical equation for the reaction of hydrogen with chlorine to form hydrogen chloride.

Write the balanced chemical equation for the reaction of zinc with sulfuric acid.

Write the word equation for the reaction: 2Na + 2H_2O \rightarrow 2NaOH + H_2

A student writes the following unbalanced equation for the reaction between barium chloride and sodium sulfate: BaCl_2 + Na_2SO_4 \rightarrow BaSO_4 + NaCl. Balance the equation and identify the precipitate formed.

Balance the following chemical equation and state the type of reaction: C_2H_5OH + O_2 \rightarrow CO_2 + H_2O

Consider the following reaction: 2Fe + 3H_2O \rightarrow Fe_2O_3 + 3H_2. How many moles of hydrogen gas are produced when 4 moles of iron react completely?

Explain why changing the coefficients in a chemical equation changes the amount of substances involved, but changing the subscripts changes the identity of the substances.