YR 9 SC - Reactions Revision Quiz 1

The Law of Conservation of Mass says that matter can neither be __________ or __________.

• created; destroyed

• recycled; renewed

• subtracted; added

• joined; separated

Substances present at the start of a chemical reaction

• subscripts
• coefficients
• reactants
• products

In a reaction A + B ----> C,  reactant A has 5g and product  C has 9g. How many grams does reactant B have? 

• 4g

• 5g

• 9g

• 14g

Is this equation balanced or unbalanced? 
H₂ + O₂ --> H₂O

• balanced
• unbalanced

A chemical reaction is a process in which

• all reactants change state

• products change into reactants

• the law of conservation of mass applies

How can a chemical equation be balanced?

• changing subscripts

• erasing elements as necessary

• adding coefficients

• adding elements as necessary

What are the products in the equation?

• Zn and CuSO₄

• Zn and Cu

• ZnSO₄ and Cu

• Zn only

Which of the following is the balanced equation for Zn + HCl --> ZnCl2 + H2?

• Zn + HCl --> 2ZnCl₂ + H₂

• Zn + 2HCl --> ZnCl₂ + H₂

• 2Zn + HCl --> 2ZnCl₂ + H₂

• Zn + 2HCl --> 2ZnCl₂ + H₂

Which of the following chemical reaction shows the production of water from hydrogen gas and oxygen gas?

• 2 H₂O → 2 H₂ + O₂

• 2 H₂ + O₂ → 2 H₂O

• 3 H₂ + O₂ → 3 H₂O

• 3 H₂O → H₂ + 3 O₂

The Law of Conservation of Mass states that in a chemical reaction,

• mass of the reactants and mass of the products are equal

• new elements are formed

• new atoms are created

• atoms are destroyed