How many moles of h2 would be contained in 4.0 l of the gas at 202.6 kpa and 127°c?

Quiz - \[02\] Exam 2

Question 1  5 / 5 points

How many moles of H2 would be contained in 4.0 L of the gas at 202.6 kPa and 127°C?

Question options:

89.6 mol

→0.24 mol

6.38 mol

0.77 mol

Question 2  5 / 5 points

The graph of several pressure-volume readings on a contained gas at constant temperature would be

Question options:

a vertical line.

a horizontal line.

a straight line.

→a curved line.

Question 3  5 / 5 points

Among the gases listed, which would have the fastest rate of effusion?

Question options:

NH3

NO2

→CH4

SO2

Question 4  0 / 5 points

Death Valley in California is 86 m below sea level. Will the partial pressure of oxygen in Death Valley be the same, lower or higher than the partial pressure of oxygen at sea level?

Question options:

×higher   (wrong)

the same

impossible to tell without additional information

lower

Question 5  0 / 5 points

A temperature of –25°C is equivalent to:

Question options:

25 K.

248 K.

→298 K.

–25 K.

Question 6  5 / 5 points

The volume (in L) that would be occupied by 5.00 mol of O2 at STP is

Question options:

0.411 L.

22.4 L.

41.6 L.

→112 L.

Question 7  5 / 5 points

If the Kelvin temperature of a gas is tripled and the volume if doubled, the new pressure will be ___.

Question options:

1/6 the original pressure

5 times the original pressure

2/3 the original pressure

→3/2 the original pressure

Question 8  5 / 5 points

The graph of a relationship between variables that is directly proportional is a straight line.

Question options:

→True

False

Question 9  5 / 5 points

Which of the following best describes the relationship of pressure and volume indicated by Boyle's Law?

Question options:

direct

→inverse

positively related

cannot be described without numbers to solve with

Question 10  5 / 5 points

If the temperature of a gas in a closed container increases

Question options:

→the pressure of the gas increases.

the pressure of the gas decreases.

the molecules collide with the walls of the container less frequently.

the average kinetic energy of the molecules decreases.

Question 11  5 / 5 points

Which of the following will increase the pressure of a gas in a closed container?  

I. part of the gas is removed  

II. the container size is decreased  

III. temperature is increased

Question options:

I and II only

→II and III only

I and III only

I, II, and II

Question 12  5 / 5 points

Absolute zero is

Question options:

–273.15°C.

the lowest possible temperature.

the temperature at which the average kinetic energy of particles would theoretically be zero.

→all of the above

Question 13  5 / 5 points

If a sample of oxygen occupies a volume of 2.15 L at a pressure of 58.0 kPa and a temperature of 25°C, what volume would this sample occupy at 101.3 kPa and 0°C?

Question options:

3.44 L

→1.13 L

1.35 L

4.10 L

Question 14  5 / 5 points

Doubling the number of particles of gas in an inflated tire will double the pressure of the gas in the tire.

Question options:

→True

False

Question 15  5 / 5 points

At constant pressure, the volume of a fixed mass of gas and its Kelvin temperature are said to be

Question options:

inversely related.

→directly related.

constant.

unrelated.

Question 16  0 / 5 points

At constant volume, if the Kelvin temperature of a gas is doubled, the pressure of the gas is halved.

Question options:

True

→False

Question 17  5 / 5 points

A sample of H2 is collected over water such that the combined hydrogen–water vapor sample is held at a pressure of 1 standard atmosphere. What is the partial pressure of the H2 if that of the water vapor is 2.5 kPa?

Question options:

→98.8 kPa

101.3 kPa

103.8 kPa

2.5 kPa

Question 18  5 / 5 points

What is the mass, in grams, of 0.125 L of CO2 at STP?

Question options:

→0.246 g

2.80 g

4.11 g

181 g

Question 19  5 / 5 points

Which of the following would double the pressure on a contained gas at constant temperature?

Question options:

doubling the volume of the container

halving the number of particles in the container

→doubling the number of particles in the container

none of the above

Question 20  5 / 5 points

The temperature of 6.24 L of a gas is increased from 25.0°C to 55.0°C at constant pressure. The new volume of the gas is

Question options:

5.67 L.

→6.87 L.

13.7 L.

2.84 L.

air quality

poor drinking water

and heavy polution

can lead to poor health

answer: the enthalpy of the overall chemical reaction is +87.88 kj or +88 kj.

according to hess's law, the overall enthalpy of a reaction is the difference between the sum of enthalpy values of all the products and the sum of enthalpy values of all the reactants.

δh(reaction) = ∑nδh(products) - ∑nδh(reactants)

δh(reaction) = [δh +δh] - [δh]

δh(reaction) = [1(-287.02) + 1(0) ] - [1(-374.9)] kj = +87.88 kj

here, δh (pcl3) = -287.02 kj, δh(cl2) = 0, δh(pcl5) = -374.9 kj

therefore, enthalpy of the overall reaction is +87.88 kj or +88 kj.