Chem 101 Quiz 4

What is the equivalent pressure of 0.805 atm in unit of mm Hg?

0.805atm*760mmHg/1atm= 611.8mm Hg

In which gas law equation, do we need to express the unit of temperature in Kelvin?

All gas laws, any kind of gas equations, including bones law, charles law, combined gas law and ideal gas law

List all the intermolecular forces exist in the following molecules: CO2 H2S CH4 F2 I2 H2 HF

Co2- dispersion force CH4- dispersion force H2-dispersion force H2S-dispersion forces and dipole-dipole forces F2- dispersion forces I2-dispersion forces HF-dispersion forces and hydrogen bonding

The temperature of a gas is _____ (inversely or directly) proportional to its pressure.

Directly. Because when T increases, P increases. When T decreases, P decreases

What are the four types of intermolecular forces names? What is the strength sequence?

Dispersion forces (weakest), dipole-dipole forces (moderate), hydrogen bonding (strong), ion-dipole force (very strong)

What is the correct sequence of increasing density of the three phases of water?

Gas<Solid<Liquid

Liquid has a ____(high or low) density and a ____(definite or indefinite) volume.

High, definite

Solid has a ____(high or low) density and a ____(definite or indefinite) volume.

High, definite

The volume of a gas is _____ (inversely or directly) proportional to its pressure.

Inversely. Because when V increases, P decreases. When V decreases, P increases

What is the type of solid for the following substance: NaCl, dry ice(CO2), Silicon, Copper

NaCl- ionic solid dry ice(CO2)- molecular solid Silicon- covalent atomic solid Copper- metallic atomic solid

According to Kinetic molecular theory, is there any strong attractive forces between the gas molecules?

No. Kinetic molecular theory says there is no forces between gas molecules

A gas cylinder contains two-part gas mixture (mixture of nitrogen gas and carbon dioxide), the total pressure is 6.0 atm with 90.0% of nitrogen, what would be the pressure due to the carbon dioxide gas component?

P(CO2)=Ptot*fraction composition of CO2 =6.0atm*(100%-90%)=0.6atm

A sample of 0.366 mole of gas has a volume of 768 mL at 29°C. Calculate the pressure of this gas. (R=0.0821 L·atm/mol·K) R (ideal gas constant) value

P=nRT/V=0.366x0.0821x(29+273.15)/0.768=11.8atm

What is the equation of ideal gas law?

PV=nRt P=nRt/V V=nRt/P T=PV/nR n=PV/RT

Suppose you had a balloon containing 2 mole of helium at STP and a balloon containing 2 mole of oxygen at STP, the two balloons will have the same _____ (volume or mass)? Use equation to explain why?

Same volume. Because at STP, regardless of the identity of the gas, 1 mole of gas takes up 22.4L volume

According to kinetic molecular theory, gas pressure results from the collision of gas molecules. True or false?

True. Gas pressure results from the collision of gas molecules and against the wall of container.

According to Kinetic molecular theory, the average kinetic energy of the gas molecules is dependent to the temperature of the gas. True or false

True. Temperature is the measurement of thermal energy. With temperature increase for gas that means more thermal energy is absorbed by gas molecules, which result in the transformation of more kinetic energy.

According to Kinetic molecular theory, the size of the gas molecules is negligible, why?

Yes. Because the distance between gas molecules are very very far compared to the size of the molecules. The distance is so far away that we can almost neglect the size of the gas molecules

The opposite process of evaporation is _____.

condensation

As increasing the intermolecular forces of a liquid, the evaporation rate will ____(increase or decrease).

decrease

As increasing the intermolecular forces of a liquid, the vapor pressure will ____(increase or decrease).

decrease

Increasing the strength of intermolecular forces can ____ (increase or decrease) the rate of vaporization.

decrease

Which intermolecular force is present in all molecules and atoms?

dispersion forces

Evaporation is ____(endothermic or exothermic) process.

endothermic

When humans sweat, what does the cooling process called?

evaporation

____ (high or low) pressure can cause gas to decrease the space between gas particles.

high

As increasing the intermolecular forces of a liquid, the surface tension will ____(increase or decrease

increase

As increasing the intermolecular forces of a liquid, the viscosity will ____(increase or decrease).

increase

Increasing the surface area can ____ (increase or decrease) the rate of vaporization.

increase

Increasing the temperature can ____ (increase or decrease) the rate of vaporization.

increase

As the temperature increases, the evaporation process ____(increase or decrease).

increases

____ (high or low) temperature can cause gas particles to slow down.

low

Gas has a ____(high or low) density and a ____(definite or indefinite) volume.

low, indefinite

Dipole-dipole forces occur between ____(polar or nonpolar) molecules.

polar