2nd Pre Test in Science 9 - Earth Science - Volcanic Eruption

What term is used to describe the molten material deep inside the Earth?

• 1. hot spot

• 1. lava

• 1. magma

• volcano

Which is NOT a contributor in the formation of magma?

• 1. pressure

• 1. composition

• 1. temperature

• distance from the core

Viscosity is a measure of a material’s resistance to flow. Which affects the viscosity of magma?

• 1. temperature of the magma

• 1. chemical composition of the magma

• 1. presence of dissolved gases in the magma

• all of the choices

Which serves as the driving force that causes magma to explode to the surface?

• 1. the gravity in the core

• 1. the mass of the magma

• 1. the silica in the magma

• the dissolved gases trapped in the magma

Magma is a mixture of minerals and volcanic gases. Which describes the composition of gases in magma?

• 1. Mostly H2O (water vapor) & some CO2 (carbon dioxide)

• 1. Major amounts of Sulfur, Chlorine, and Fluorine gases

• 1. Mostly CO2 (carbon dioxide) and few H2O (water vapor)

• Mostly SO2 (sulfur dioxide) and some H2O (water vapor)

What are the characteristics of magma that create explosive eruptions?

• 1. high gas content and high viscosity

• 1. low gas content and low viscosity

• 1. high gas content and low viscosity

• low gas content and high viscosity

What would magma with the highest viscosity contain?

• 1. a high silica content and high temperature.

• 1. a high silica content and low temperature.

• 1. a low silica content and high temperature.

• a low silica content and low temperature.

At depth in the Earth, nearly all magmas contain gas dissolved in liquid. When do the gases form into a separate vapor phase?

• 1. When volume of gas is reduced as pressure increased.

• 1. When volume of gas expands as pressure is increased.

• 1. When pressure is decreased as magma rises toward the surface of the Earth.

• When pressure is increased as magma rises toward the surface of the Earth.

Which type of volcano ejects a basaltic magma?

• 1. Cinder cone

• 1. Composite

• 1. Shield

• Stratovolcanoes

In magma formation, what should be the temperature and pressure requirements?

• 1. High temperature and high pressure

• 1. Low temperature and low pressure

• 1. High temperature and low pressure

• High pressure and low temperature