Q3 - Chemical Reactions and Equations

What is matter?

• Matter is made of atoms.

• Matter is a measure of the amount of material in an object.

• Matter may exist as a solid, liquid, or a gas.

• Matter forms when particles chemically bond together.

• Matter includes both elements and compounds.

What type of chemical reaction is burning paper?

• Chemical

• Physical

What breaks during a chemical reaction?

• glass

• bonds

• molecules

• atoms

Instead of using a chemical's long name, scientists use this instead when writing a chemical equation.

• Shorthand

• Braile

• Elemental symbols

• Elemental Code

How do you know a chemical reaction has occured?

• Properties of the materials change.

• Energy in the system changes.

• Both A & B are correct.

• Neither A nor B are correct

When I want to balance a chemical equation, this is the only number that I can change.

• Subscript

• Coefficient

• Elemental Symbol

• Yields

The subscript tells you how many of what there are in a chemical reaction?

• atoms of that element

• molecules of that compound

• number of reactions

• They don't tell you anything.

A coefficient tells you what about the chemical reaction?

• Numbers of atoms in that element

• Numbers of molecules for that compound.

• How many reactions there are.

• They don't tell you anything.

A teacher writes the equation representing the chemical reaction between hydrochloric acid and sodium on the board.HCl + Na → NaCl + H₂The teacher states that the equation has not been balanced. Which of these correctly shows the products of this reaction after the equation has been balanced?

• Na₂Cl + H₂
•  2NaCl + H₂
• NaCl + 2H₂
•  2NaCl + 2H₂

Which among the following is(are) double displacement reaction(s)?(i) Pb + CuCl2 → PbCl2 + Cu (ii) Na2SO4 + BaCl2 → BaSO4 + 2NaCl (iii) C + O2 → CO2 (iv) CH4 + 2O2 → CO2 + 2H2O

• (i) and (iv)
• (ii) only
• (i) and (ii)
• (iii) and (iv)