Q1) in which of the following layers is atmospheric pressure the lowest?

a. troposphere
b. stratosphere
c. thermosphere
d mesosphere

q2) most of the earth's atmosphere is composed of which of the following two gases?

a. nitrogen and carbon dioxide
b. nitrogen and oxygen
c. methane and argon
d. carbon dioxide and oxygen

q3) what is barometric pressure?

a. the increase in the weight of the atmosphere as elevation increases
b. the pressure of 1 metric ton of seawater
c. the increase in temperature as elevation increases
d. the pressure the atmosphere exerts on an object

Q1

C. Thermosphere is the layer of very rare air above the mesosphere. The air in this layer is so thin that it would feel freezing cold to us. Many satellites actually orbit Earth within the thermosphere so it is more like outer space than a part of the atmosphere. Variations in the amount of energy coming from the Sun exert a powerful influence on both the height of the top of this layer and the temperature within it.

Q2

A. Nitrogen and oxygen are the two most common gases that composes the atmosphere; dry air is composed of about 78% nitrogen (N2) and about 21% oxygen (O2). Argon, carbon dioxide (CO2), and many other gases are also present in much lower amounts; each makes up less than 1% of the atmosphere's mixture of gases. The atmosphere also includes water vapor.

Q3

1) Answer is: c. Thermosphere.

Moving upward from ground level, layers of Earth's atmosphere are: the troposphere, stratosphere, mesosphere and thermosphere.

The troposphere is the lowest layer of our atmosphere with highest pressure. It extends upward to about 10 km above sea level. Air pressure drops, moving higher in the troposphere.

The stratosphere extends from the top of the troposphere to about 50 km above the ground.

Mesosphere extends upward to a height of about 85 km above Earth. The pressure continues dropping as go higher.

Thermosphere is between 500 and 1000 km above the ground.

2) Answer is: b. Nitrogen and Oxygen.

Together, nitrogen (N₂) and oxygen (O₂) by volume account for 99,03% of the gases composing the dry air in the lower atmosphere.

Volume of nitrogen in air is 78,08%.

Volume of oxygen in air is 20,95%.

Together: 78,08% + 20,95% = 99,03%.

This gases can be separated by fractional distillation of liquefied air.

3) Answer is: d. The pressure the atmosphere exerts on an object.

Barometric pressure (atmospheric pressure), is the pressure within the atmosphere of Earth

Atmospheric pressure decreases with increasing height, because there are fewer air molecules above a given object.

Barometer is an instrument used in meteorology to measure atmospheric pressure.

the volume of fluid displaced would equal the volume of the gas. use a gas syringe - this is a laboratory instrument that can be used to withdraw a certain volume of gas from a closed system or to measure the volume of gas from a chemical reaction.