NC Chemistry Comprehensive Exam

What is the chemical formula for magnesium bromate?

• MgBr

• MgBr₂

• MgBrO₃

• Mg(BrO₃)₂

How are compounds with metallic bonds similar to ionic compounds?

• Both tend to have double and triple bonds.

• Both tend to have low boiling points.

• Both tend to have poor conductivity.

• Both tend to have high melting points.

Tags

NGSS.HS-PS1-1

Which of these elements has the greatest atomic radius?

• H

• Cl

• N

• Cs

How does the amount of heat energy change as a 250-g sample of water is heated from 5.0°C to 30.0°C?

• The amount of heat energy increases, causing the water to sublime.

• The amount of heat energy increases, causing the water to evaporate.

• As the temperature increases, the amount of heat energy decreases.

• As the temperature increases, the amount of heat energy increases.

Tags

NGSS.HS-PS3-4

This graph represents data collected when a sample of a gas is uniformly cooled from 155°C. Why does the temperature of the sample remain constant between point X and

point Y? (phase changes/cooling/heating curves)

• because the sample is transitioning from a gaseous state to a solid state

• because the sample is transitioning from a gaseous state to a liquid state

• because the sample is transitioning from a solid state to a gaseous state

• because the sample is transitioning from a liquid state to a solid state

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

The phases of a substance under various pressure and temperature combinations are shown on this phase diagram. What occurs if the pressure of the substance at point F remains constant, and the temperature increases to point G? (phase changes and phase diagrams)

• It will transition from a solid state to a liquid state.

• It will transition from a liquid state to a solid state.

• It will transition from a solid state to a gaseous state.

• It will transition from a gaseous state to a solid state.

Tags

NGSS.HS-PS3-4

The potential energy diagram of a chemical reaction is shown . Which best describes the energy in the chemical reaction? (energy diagrams/Activation Energy)

• Heat energy was released.

• Energy was lowered by a catalyst.

• 8 J of energy were required to start the reaction.

• 10 J of energy were required to start the reaction.

Tags

NGSS.HS-PS1-4

This balanced chemical equation represents a chemical reaction: 6NO + 4NH₃ → 5N₂ + 6H₂O

What volume of NH₃ gas, at Standard Temperature and Pressure (STP), is required to react with 15.0 g of NO? (Stoichiometry)

• 5.68 L

• 7.47 L

• 10.0 L

• 11.2 L

Tags

NGSS.HS-PS1-7

The equation represents a chemical reaction at equilibrium.

HCl (aq) + Mg (s) → MgCl₂ (aq) + H₂ (g) + heat

What happens to the system when the temperature is decreased? (reversible reactions)

• The reaction shifts toward the right, and the amount of hydrogen gas increases.

• The reaction shifts toward the right, and the amount of hydrogen gas decreases.

• The reaction shifts toward the left, and the amount of hydrogen gas

  increases.

• The reaction shifts toward the left, and the amount of hydrogen gas

  decreases.

Tags

NGSS.HS-PS1-5

NGSS.HS-PS1-6

This equation represents a chemical reaction at equilibrium:

2SO₂ (g) + O₂ (g) ↔2SO₃ (g)

What will happen when the concentration of SO₃ is increased? (reversible reactions)

• The reaction shifts to the right, and concentrations of SO₂ (g) and O₂ (g) decrease.

• The reaction shifts to the right, and concentrations of SO₂ (g) and O₂ (g) increase.

• The reaction shifts to the left, and concentrations of SO₂ (g) and O₂ (g) decrease.

• The reaction shifts to the left, and concentrations of SO₂ (g) and O₂ (g) increase.

Tags

NGSS.HS-PS1-5