1.
An ideal gas is a hypothetical gas
Correct Answer
B. That conforms to all of the assumption of the kinetic theory
Explanation
The correct answer is "that conforms to all of the assumptions of the kinetic theory". This is because the kinetic theory of gases assumes that gas particles are in constant random motion, have negligible volume, and do not interact with each other. Therefore, an ideal gas is a hypothetical gas that follows all of these assumptions of the kinetic theory.
2.
Which branch of chemistry deals with the mass relationships of elements in compounds and the mass relationships among reactants and products in chemical reactions
Correct Answer
D. Stoichiometry
Explanation
Stoichiometry is the branch of chemistry that deals with the mass relationships of elements in compounds and the mass relationships among reactants and products in chemical reactions. It involves the calculation of the quantities of reactants and products in a chemical reaction based on the balanced equation. This helps in determining the amount of each substance needed for a reaction and predicting the amount of product that will be formed.
3.
What is the study of the mass relationships among reactants and products in a chemical reaction?
Correct Answer
B. Composition stoichiometry
Explanation
Composition stoichiometry is the study of the mass relationships among reactants and products in a chemical reaction. It involves determining the quantities of reactants needed to produce a certain amount of product, as well as the quantities of products that can be obtained from a given amount of reactants. This branch of stoichiometry focuses on the composition or makeup of the substances involved in the reaction and how they combine or transform during the reaction.
4.
What is the study of the mass relationships among reactants and products in a chemical reaction
Correct Answer
A. Reaction stoichiometry
Explanation
Reaction stoichiometry is the study of the mass relationships among reactants and products in a chemical reaction. It involves determining the balanced chemical equation and using stoichiometric coefficients to determine the amount of reactants needed and the amount of products produced. This helps in understanding the quantitative aspects of a chemical reaction, such as the amount of substances involved and the ratios in which they react or are produced.
5.
In what kind of reaction do two or more substances combine to form a new compound?
Correct Answer
D. Synthesis reaction
Explanation
A synthesis reaction is a type of chemical reaction where two or more substances combine to form a new compound. In this reaction, the reactants come together to create a single product. This is the opposite of a decomposition reaction, where a compound breaks down into its individual elements. Combustion reactions involve the rapid combination of a fuel with oxygen, resulting in the release of energy. Double-displacement reactions occur when the cations and anions of two different compounds switch places to form two new compounds. Therefore, the correct answer is synthesis reaction.
6.
When the limiting reactant in a chemical reaction is completely used, the
Correct Answer
D. Reaction stops
Explanation
When the limiting reactant in a chemical reaction is completely used, it means that there are no more molecules of the limiting reactant available to react. As a result, the reaction cannot proceed any further because there are no more reactants to participate in the reaction. Therefore, the reaction stops.
7.
What is the measured amount of a product obtained from a chemical reaction?
Correct Answer
D. Actual yield
Explanation
The actual yield is the measured amount of a product obtained from a chemical reaction. It represents the amount of product that is actually produced in the reaction, taking into account any limitations or inefficiencies in the process. The actual yield is often compared to the theoretical yield, which is the amount of product that would be obtained if the reaction proceeded perfectly according to stoichiometry. The percentage yield is then calculated by dividing the actual yield by the theoretical yield and multiplying by 100. The mole ratio, on the other hand, is a ratio that relates the number of moles of one substance to another in a balanced chemical equation.
8.
Pressure is the force per unit
Correct Answer
B. Surface area
Explanation
Pressure is defined as the force applied per unit area. In this context, the correct answer is surface area because pressure is the force per unit surface area. It is a measure of how much force is applied over a given area. The larger the surface area, the lower the pressure, as the force is spread out over a larger area. Conversely, a smaller surface area will result in higher pressure, as the force is concentrated on a smaller area. Therefore, surface area is directly related to pressure.
9.
What is the SI unit of force
Correct Answer
D. Newton
Explanation
The SI unit of force is the newton. It is named after Sir Isaac Newton, who made significant contributions to the field of physics. The newton is defined as the force required to accelerate a one-kilogram mass by one meter per second squared. It is widely used in scientific calculations and measurements involving force.
10.
If force is held cosntant as surface area decreases, pressure
Correct Answer
C. Increases
Explanation
As the surface area decreases while the force remains constant, the same force is applied over a smaller area. This results in a higher pressure because pressure is defined as force per unit area. So, as the area decreases, the force is distributed over a smaller area, leading to an increase in pressure.
11.
What does the constant bombardment of gas molecules against the inside walls of a container produce?
Correct Answer
C. Pressure
Explanation
The constant bombardment of gas molecules against the inside walls of a container produces pressure. When gas molecules collide with the walls of the container, they exert a force, which creates pressure. The more frequently and forcefully the molecules collide, the higher the pressure. Pressure is a measure of the force exerted per unit area, and it is a result of the random motion of gas molecules.
12.
Which instrument measures atomospheric pressure?
Correct Answer
A. Barometer
Explanation
A barometer is an instrument used to measure atmospheric pressure. It works by balancing the pressure exerted by the atmosphere with the pressure exerted by a column of liquid, usually mercury or water. Changes in atmospheric pressure cause the liquid level in the barometer to rise or fall, indicating changes in weather conditions. A manometer, on the other hand, measures pressure in closed systems, such as gas tanks or pipes, while a vacuum pump is used to create a vacuum by removing air or gas from a sealed space. A torrometer is not a valid instrument for measuring atmospheric pressure.
13.
Which insturment measures the pressure of an enclosed gas
Correct Answer
B. Manometer
Explanation
A manometer is an instrument used to measure the pressure of an enclosed gas. It consists of a U-shaped tube filled with a liquid, such as mercury or water, and the gas pressure is measured by the difference in height of the liquid in the two arms of the tube. This device is commonly used in various applications, such as monitoring gas pressure in pipes, tanks, or other closed systems. A barometer measures atmospheric pressure, a vacuum pump creates a vacuum, and a torrometer is not a recognized instrument.
14.
Convert the pressure 0.75 atm to mm Hg
Correct Answer
C. 570 mm Hg
Explanation
To convert the pressure from atm to mm Hg, we need to multiply the given value by the conversion factor of 760 mm Hg/1 atm. Therefore, 0.75 atm multiplied by 760 mm Hg/1 atm equals 570 mm Hg.
15.
Standard temperature is exactly
Correct Answer
C. 0 C
Explanation
Standard temperature is defined as 0 degrees Celsius. It is the temperature at which water freezes and forms ice under normal atmospheric pressure. This temperature is widely used as a reference point for various scientific and industrial applications, including the calibration of thermometers and the measurement of other physical properties.
16.
Standard pressure is the pressure exerted by a column of mercury exactly
Correct Answer
B. 760 mm high
Explanation
Standard pressure is defined as the pressure exerted by a column of mercury exactly 760 mm high. This is because the unit of pressure, called the torr, is based on the height of a column of mercury in a barometer. At sea level, the average atmospheric pressure is equal to the weight of a column of mercury that is 760 mm high. Therefore, 760 mm is the standard height used to measure pressure in this context.
17.
Standard pressure is the pressure exerted by a column of mercury exactly
Correct Answer
B. 760 mm high
Explanation
Standard pressure is defined as the pressure exerted by a column of mercury exactly 760 mm high. This is because the unit of pressure, called the atmosphere (atm), was originally defined as the average pressure at sea level. To measure this pressure, a barometer is used, which consists of a column of mercury in a tube. When the height of the mercury column is 760 mm, it balances the atmospheric pressure and is considered the standard reference point for pressure measurements. Therefore, the correct answer is 760 mm high.
18.
A sample of oxygen occupies 560. mL when the pressure is 800.00 mm Hg. At constant temperature, what volume does the gas occupy when the pressure decreases to 700.0 mm Hg
Correct Answer
D. 640 mL
Explanation
According to Boyle's Law, the volume of a gas is inversely proportional to its pressure when the temperature is constant. In this case, the initial volume of the oxygen is 560 mL and the initial pressure is 800.0 mm Hg. When the pressure decreases to 700.0 mm Hg, the volume of the gas will increase. Using the formula P1V1 = P2V2, we can calculate the final volume of the gas. Rearranging the formula, we get V2 = (P1V1)/P2. Plugging in the values, we get V2 = (800.0 mm Hg * 560 mL) / 700.0 mm Hg = 640 mL. Therefore, the correct answer is 640 mL.
19.
The gas pressure inside a container decreases when
Correct Answer
B. The number of gas molecules is decreased
Explanation
When the number of gas molecules is decreased, the gas pressure inside a container decreases. This is because with fewer gas molecules, there are fewer collisions between the molecules and the walls of the container, resulting in less force exerted on the walls. As a result, the gas pressure decreases.
20.
The standard molar volume of a gas at STP is
Correct Answer
A. 22.4 L
Explanation
The standard molar volume of a gas at STP is 22.4 L. This means that at standard temperature and pressure (STP), one mole of any gas occupies a volume of 22.4 liters. This value is derived from the ideal gas law, which states that at STP, one mole of an ideal gas occupies a volume of 22.4 liters. Therefore, the correct answer is 22.4 L.
21.
The standard molar volume of a gas at STP is
Correct Answer
A. 22.4 L
Explanation
The standard molar volume of a gas at STP is 22.4 L. This means that at standard temperature and pressure, one mole of any gas occupies a volume of 22.4 liters. This value is derived from the ideal gas law equation, where the volume of a gas is directly proportional to the number of moles present. Therefore, at STP, the molar volume is a constant value of 22.4 L.