Chemical Reactions Review

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

• (s)

• (l)

• (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?

• A. It conducts heat.

• B. It reacts with nitric acid to produce a gas.

• C. It has a density of 10.49 g/cm³.

• D. It is powdery white.

Tags

NGSS.MS-PS1-2

How many atoms of oxygen are represented in 2Mg(SO₄)₂?

• A. 2

• B. 4

• C. 8

• D. 16

Tags

NGSS.MS-PS1-1

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

• A. precipitate

• B. oxide

• C. salt

• D. hydrocarbon

Tags

NGSS.MS-PS1-2

Classify the following reaction: HCl(aq) + NaOH(aq) ⟶ NaCl(aq) + H₂O(l)

• A. Double replacement

• B. Single replacement

• C. Combustion

• D. Decomposition

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

• A. It is endothermic.

• B. Overall, it releases energy.

• C. It is in equilibrium.

• D. It is reversible.

Tags

NGSS.HS-PS1-4

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

• A. subscripts

• B. superscripts

• C. coefficients

• D. formulas

Tags

NGSS.HS-PS1-7

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

• A. It is a double replacement reaction.

• B. It is a decomposition reaction.

• C. It is a synthesis reaction.

• D. The reaction will not occur.

Tags

NGSS.MS-PS1-2

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

• A. Formation of a precipitate

• B. Production of a gas

• C. State of matter change

• D. Sudden release of light

Tags

NGSS.MS-PS1-2

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.

Tags

NGSS.HS-PS1-6