Chemical Reactions Test

In a chemical equation, “dissolved in water” is represented by which of the following symbols?

• (s)
• (1)
• (g)
• (aq)

Two students conduct several tests to determine the identity of an unknown metal. They noted that it was powdery white, conducted both heat and electricity, and had a density of 10.49 g/cm3. It did not react with water but, with nitric acid it released a gas. What evidence above supports a chemical change in this unknown?

• It conducts heat.
• It reacts with nitric acid to produce a gas.
• It has a density of 10.49 g/cm3.
• It is powdery white.

How many atoms of oxygen are represented in 2Pb(SO4)2.

• 2
• 4
• 8
• 16

A solid produced from two aqueous solutions in a chemical reaction is known as a(n) _____ .

• precipitate
• oxide
• salt
• hydrocarbon

Classify the following reaction: HCl(aq) + NaOH(aq) -> NaCl(aq) + H2O(l).

• Double replacement
• Single replacement
• Combustion
• Decomposition

Which of the following statements about the reaction below is not true? N2(g) + 3H2(g) ⇌ 2NH3(g) + energy

• It is endothermic.
• Overall, it releases energy.
• It is in equilibrium.
• It is reversible.

To balance a chemical equation, it may be necessary to change the substances’ _______ .

• subscripts
• superscripts
• coefficients
• formulas

Which of the following statements best describes the following reaction? MgCl2 + I2 à MgI2 + Cl2

• It is a double replacement reaction.
• It is a decomposition reaction.
• It is a synthesis reaction.
• The reaction will not occur.

Which of the following would not be considered evidence of a chemical reaction?

• Formation of a precipitate
• Production of a gas
• State of matter change
• Sudden release of light

Which of the following statements is true about chemical equilibrium?

• The reaction has reached its end.
• The forward and reverse reactions occur at the same rate.
• The concentration of reactants is higher than the concentration of products.
• The amount of reactants and products is the same.