CHEMICAL EQUATIONS AND REACTION TYPES

Multiple Choice

Which of the following is an example of a chemical change?

• Melting ice

• Burning paper

• Dissolving sugar in water

• Breaking glass

Open Ended

Why is it important to understand chemical changes in everyday life?

Multiple Choice

Which of the following is NOT a sign of a chemical change?

• Formation of a gas

• Permanent color change

• Formation of a precipitate

• Melting of ice

Multiple Select

Which of the following are signs that a chemical change has occurred?

• Production of light

• Change in energy

• Change in shape

• Formation of a precipitate

Fill in the Blank

A chemical equation is a symbolic way of representing a chemical ___.

Open Ended

Explain the Law of Conservation of Mass and how it applies to chemical equations.

Multiple Choice

Which of the following molecules is diatomic when uncombined?

• CO2

• O2

• H2O

• NaCl

Fill in the Blank

The symbol (aq) in a chemical equation stands for ___ solution.

Fill in the Blank

You NEVER change ___ when balancing a chemical equation.

Open Ended

Explain why it is important to use coefficients rather than changing subscripts when balancing chemical equations.

Multiple Choice

What is the main difference between subscripts and coefficients in a chemical equation?

• Subscripts indicate the number of atoms in a molecule, while coefficients indicate the number of molecules or compounds.

• Subscripts are used to balance equations, while coefficients are not.

• Coefficients are always smaller than subscripts.

• Subscripts are written in front of compounds, while coefficients are written after.

Multiple Choice

In the balanced equation 2H₂ + O₂ → 2H₂O, how many molecules of water are produced from 2 molecules of O₂?

• 2

• 4

• 1

• 3

Fill in the Blank

The sum of the coefficients in the balanced equation for CH₄ + 2O₂ → CO₂ + 2H₂O is ___

Multiple Select

Which of the following are steps in balancing a combustion reaction?

• Balance the carbon atoms.

• Balance the hydrogen atoms.

• Balance the oxygen atoms first.

• Check to see that everything is balanced.

Multiple Choice

Which type of reaction involves two or more reactants combining to form a single product?

• Synthesis reaction

• Decomposition reaction

• Single replacement reaction

• Double replacement reaction

Multiple Select

Which of the following are products of a combustion reaction involving a hydrocarbon and oxygen?

• CO2

• H2O

• O2

• CH4

Fill in the Blank

In a double replacement reaction, two compounds exchange ___ to form new compounds.

Multiple Choice

What must be true about the uncombined element in a single-replacement reaction for the reaction to occur?

• It must be higher than the element in the compound on the activity series.

• It must be lower than the element in the compound on the activity series.

• It must be the same as the element in the compound.

• It must be a noble gas.

Open Ended

Explain how you would use the activity series to predict whether a single-replacement reaction will occur between two elements.

Open Ended

Describe the difference between a precipitation reaction and an acid-base neutralization reaction, both of which are types of double replacement reactions.

Multiple Choice

What is a precipitate in the context of double replacement reactions?

• A gas formed during a reaction

• A solid product formed when two solutions are mixed

• A liquid that evaporates

• A color change in the solution

Multiple Choice

According to the solubility rules, which of the following compounds would be insoluble in water?

• NaNO3

• KCl

• AgCl

• NH4Br

Fill in the Blank

Fill in the blank: Compounds containing the ion ___ are generally insoluble unless combined with Li+, Na+, K+, or NH4+.

Multiple Select

Based on the solubility rules, select all the ions that, when present in a compound, generally make it soluble in water.

• Li+

• NO3-

• CO3 2-

• NH4+

Open Ended

Explain the difference between an overall ionic equation and a net ionic equation in double replacement reactions.

Multiple Choice

Given the reaction K2SO4(aq) + Ba(NO3)2(aq) → 2 KNO3(aq) + BaSO4(s), what is the net ionic equation?

• K2SO4(aq) + Ba(NO3)2(aq) → 2 KNO3(aq) + BaSO4(s)

• 2 K+(aq) + SO4 2-(aq) + Ba2+(aq) + 2 NO3-(aq) → 2 K+(aq) + 2 NO3-(aq) + BaSO4(s)

• Ba2+(aq) + SO4 2-(aq) → BaSO4(s)

• K+(aq) + NO3-(aq) → KNO3(aq)

Open Ended

How would you explain the difference between a chemical change and a physical change to someone who is new to chemistry?

Multiple Choice

What is a chemical change?

• A change where a new substance with different chemical properties is formed

• A change where the physical state changes but the substance remains the same

• A process that only involves mixing substances without any reaction

• A process where energy is always absorbed without forming new substances