Chemistry Review 24

Which statement best explains how the periodic table is organized?

• increasing atomic number from left to right

• increasing number of neutrons from left to right

• decreasing number of electrons from left to right

• decreasing atomic mass number from left to right

How does a balanced chemical equation satisfy the Law of Conservation of Mass?

• During a chemical reaction, the total amount of matter stays the same.

• During a chemical reaction, matter is destroyed.

• During a chemical reaction, one or more new substances are formed.

• During a chemical reaction, the total number of atoms increases.

Tags

NGSS.MS-PS1-5

Which best explains why the total mass of the product(s) would be less than the total mass of the reactant(s) after a chemical reaction?

• A physical change occurred.

• Atoms involved in the reaction lost mass.

• Precipitates were created in the new solution.

• Gases were released to the atmosphere.

Tags

NGSS.MS-PS1-5

Chemical formulas for several common substances are listed in the table. Why does hydrogen (H) have a different subscript in each substance?

• The subscript indicates the number of hydrogen atoms in each substance.

• The subscript indicates the number of mixtures that the hydrogen is forming.

• The subscript indicates the number of compounds that the hydrogen is forming.

• The subscript indicates whether the hydrogen is forming a compound or a mixture.

Tags

NGSS.MS-PS1-1

Which best describes how to balance the chemical equation shown below to support the law of conservation of mass? Mg + O₂ → MgO

• Add the coefficient 2 before the Mg on both sides of the equation.

• Add the coefficient 2 before the O2 on the left side of the equation.

• Add the coefficient 2 before the Mg on the left side of the equation.

• Add the coefficient 2 before the MgO on the right side of the equation.

Tags

NGSS.MS-PS1-5

Which products would balance the equation below?

CaCl₂ + 2Li →

• LiCl + Ca

• Li₂Cl + Ca

• 2LiCl + Ca

• LiCl₂ + 2Ca

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

The following chemical reaction occurs:

2H₂O₂ → 2H₂O + O₂

How many atoms of hydrogen are involved in the reaction?

• 1

• 2

• 4

• 8

Tags

NGSS.MS-PS1-1

Where on the periodic table are you most likely to find elements that do not react with other elements?

• group 1

• group 2

• group 17

• group 18

Which subatomic particles determine the reactivity of groups of elements in the periodic table?

• electrons

• neutrons

• protons

• atoms

What is the best way to measure the gas produced in a chemical reaction?

• Perform the experiment in a beaker.

• Perform the experiment in a room.

• Perform the experiment in a closed system.

• Perform the experiment in an open system.