Chemical Processes and Equations

How many HCl molecules do you need to balance the chemical equation below? Mg + __HCl → MgCl2 + H2

• 2

• 12

• 5

• 1

The synthesis reaction can also be named by____________. (Select all that apply).

• Decomposition

• Buring

• Combination

• Composition

• Replacement

A reaction that always starts with a Hydrocarbon that reacts with oxygen and produces carbon dioxide and water.

In the reaction below, water is a ________________.

• Reactant

• Product

• A and B are correct

• None of the above.

Evidence of a chemical reaction is anything that shows ____________.

• a new substance has formed

• a solid dissolved in a liquid

• interaction between 2 gases

• a change in the state of matter

Decomposition is the opposite reaction of ______________.

• Synthesis

• Combustion

• Single replacement

• Double replacement

Choose the correct answer: The number to the lower side of an element is a __________.

• Subscript

• Superscript

• Coefficient

• B and C are correct

The Law of Conservation of matter states that _____________.

• Mass is created in a chemical reaction

• Mass is created in a physical change

• New chemicals formed from a chemical reaction have a larger overall mass than the original reactants

• Mass is never created or destroyed

The arrow in a chemical equation points to the ____________.

• Reactants

• Reactants and products

• Products

• Sometimes point to the reactants while other times point to the products.

A student places a piece of a potato into a container of hydrogen peroxide. One observation the student makes is that bubbles form around the potato. The presence of bubbles might indicate the formation of a new substance because _____________.

• Bubbles could show that a gas is forming.

• Bubbles always rise to the top of a liquid.

• Bubbles are almost always perfectly spherical.

• Bubbles usually burst after a few minutes.