What is the chemical formula for magnesium bromate?

• MgBr

• MgBr₂

• MgBrO₃

• Mg(BrO₃)₂

Answer explanation

Mg is 2+ and BrO3 is 1-, so as indicated by the formula 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

Answer explanation

Both tend to have high melting points

Which of these elements has the greatest atomic radius?

• H

• N

• Cl

• Cs

Answer explanation

Cs has the greatest atomic radius among the given elements as it is located at the bottom of the periodic table, indicating larger atomic size. Atomic radius tends to increase to the left and to the bottom on the P.T.

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.

Answer explanation

Temperature as a measure of the average kinetic energy, which relates to the heat

Tags

NGSS.HS-PS3-2

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?

• 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

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?

• 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.

The potential energy diagram of a chemical reaction is shown below. Which best describes the energy in the chemical reaction?

• 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?

• 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.

What happens to the system when the temperature is decreased?

• 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

This equation represents a chemical reaction at equilibrium:

2SO₂ (g) + O₂ (g) ⇌ 2SO₃ (g)

What will happen when the concentration of SO3 is increased?

• 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

NGSS.HS-PS1-6