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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 11
A chemical equation is said to be balanced when:
A student writes the following equation: N_2 + 3H_2 \rightarrow 2NH_3. How many molecules of hydrogen are required to react with one molecule of nitrogen?
A student writes the following equation: Zn + HCl \rightarrow ZnCl_2 + H_2. Is this equation balanced? If not, provide the balanced equation.
Balance the following equation: Al + HCl \rightarrow AlCl_3 + H_2
Balance the following equation: C_3H_8 + O_2 \rightarrow CO_2 + H_2O
Balance the following equation: Fe + O_2 \rightarrow Fe_2O_3
Balance the following equation: \mathrm{H_2SO_4} + \mathrm{NaOH} \rightarrow \mathrm{Na_2SO_4} + \mathrm{H_2O}
Balance the following equation: \mathrm{Na} + \mathrm{O_2} \rightarrow \mathrm{Na_2O}
Balance the following equation: \mathrm{Pb(NO_3)_2} + \mathrm{KI} \rightarrow \mathrm{PbI_2} + \mathrm{KNO_3}
Explain the difference between a word equation and a chemical equation.
Explain why it is important to indicate the physical states of reactants and products in a chemical equation.
Explain why subscripts in chemical formulas should not be changed when balancing chemical equations.
State the law that requires chemical equations to be balanced.
What does the symbol (aq) represent in a chemical equation?