Three volatile compounds X,Y, and Z each contain elements Q. The precent by weight of element Q in each compound was determined. Some of the data obtained are given below

Percent by weight Molecular
Compound of Element Q Weight

X 64.8% ?
Y 73.0% 104.
Z 59.3% 64.0
(a) the vapor density of compound X at 27 degress C and 750.mm Hg was determined to be 3.53 grams per litre. Calculate the molecular weight of compound X.

(b) Determine the mass of the element Q contained in 1.00 mole of each of the three compounds.

(c) Calculate the most probable value of the atomic weight of element Q

(d) Compound Z contains carbon, hydrogen, and element Q. When 1.00 gram of compound Z is oxidized and all of the carbon and hydrogen are converted to oxidized, 1.37 grams of CO2 and 0.281 gram of water are produced. determine the most prbable molecular formula of compound Z

Frankly, I understand the question but I don't understand the data. It may be that the spacing is not right since these posting sites don't handle spacing very well. You might try to show the data in a different form to see if that would help. One way to handle the spacing ability of these sites, or lack thereof, is to use periods. For example, if I try to make a table with columns, like this, notice that it posts with no space between and the numbers run together. It is impossible to know which number goes with which column.
properties molecular weight time of day
none 104 10:55 But I can use periods to help separate like this,
properties molecular weight time of day
none..........105.............10:55

Try something like that; perhaps someone will be able to help.

2.456

a. MM=drt/p=(3.53g/l)(62.4)(300k)/750mmHg=88.1g/mol

I have this exact question. It sucks. This is the worst class I've ever taken in my life. No joke. There's too much information to learn in one year and the review book even tells me that. It has ruined my entire junior year.

I apologize for the confusion caused by the formatting of the data. Let's reorganize the information to make it easier to understand:

Compound X:
- Percent by weight of element Q: 64.8%
- Molecular weight: ? (Unknown)

Compound Y:
- Percent by weight of element Q: 73.0%
- Molecular weight: 104

Compound Z:
- Percent by weight of element Q: 59.3%
- Molecular weight: 64.0

Now, let's address each part of the question step by step:

(a) To calculate the molecular weight of compound X, we need additional information. However, it is mentioned that the vapor density of compound X at 27 degrees Celsius and 750 mm Hg is 3.53 grams per liter. We can use the vapor density to estimate the molecular weight. The relationship between vapor density and molecular weight is given by the equation:
Molecular weight = 2 * vapor density

Substituting the given value of vapor density:
Molecular weight = 2 * 3.53 grams per liter
Molecular weight = 7.06 grams per mole

Therefore, the molecular weight of compound X is 7.06 grams per mole.

(b) To determine the mass of element Q contained in 1.00 mole of each compound, we can use the percent by weight of element Q.

For compound X:
Mass of element Q = Percent by weight / 100 * Molecular weight
Mass of element Q = 64.8 / 100 * 7.06 grams
Mass of element Q = 4.577 grams

For compound Y:
Mass of element Q = Percent by weight / 100 * Molecular weight
Mass of element Q = 73.0 / 100 * 104 grams
Mass of element Q = 75.92 grams

For compound Z:
Mass of element Q = Percent by weight / 100 * Molecular weight
Mass of element Q = 59.3 / 100 * 64.0 grams
Mass of element Q = 37.952 grams

Therefore, the mass of element Q contained in 1.00 mole of each compound is:
- Compound X: 4.577 grams
- Compound Y: 75.92 grams
- Compound Z: 37.952 grams

(c) To calculate the most probable value of the atomic weight of element Q, we need to calculate the average atomic weight. We can use the mass of element Q in 1.00 mole of each compound calculated in part (b) and find the average.

Average Atomic Weight = (Mass of element Q in compound X + Mass of element Q in compound Y + Mass of element Q in compound Z) / 3
Average Atomic Weight = (4.577 + 75.92 + 37.952) / 3
Average Atomic Weight = 39.816 grams

Therefore, the most probable value of the atomic weight of element Q is 39.816 grams.

(d) To determine the most probable molecular formula of compound Z, we need to analyze the oxidation products obtained when 1.00 gram of compound Z is oxidized.

Given:
Mass of CO2 produced = 1.37 grams
Mass of H2O produced = 0.281 gram

From the masses of CO2 and H2O, we can calculate the moles of carbon and hydrogen present in the reaction.

Moles of carbon = Mass of CO2 / Molar mass of CO2
Moles of carbon = 1.37 grams / 44.01 grams per mole
Moles of carbon = 0.0311 moles

Moles of hydrogen = Mass of H2O / Molar mass of H2O
Moles of hydrogen = 0.281 grams / 18.02 grams per mole
Moles of hydrogen = 0.0156 moles

Now, based on the Law of Multiple Proportions, we can determine the simplest whole number ratio between carbon, hydrogen, and element Q. To do this, we need to calculate the ratio of moles of carbon, hydrogen, and element Q.

Mole ratio of carbon to hydrogen = Moles of carbon / Moles of hydrogen
Mole ratio of carbon to hydrogen = 0.0311 moles / 0.0156 moles
Mole ratio of carbon to hydrogen = 1.99

Therefore, in the most probable molecular formula of compound Z, the ratio of carbon to hydrogen is approximately 1:2.

Since compound Z contains element Q, the formula of compound Z can be represented as CxHyQz. However, without further information about the ratio of element Q to carbon and hydrogen, it is not possible to determine the specific molecular formula of compound Z.

I apologize for the confusion caused by the formatting of the data. However, I can still provide explanations and assistance based on the information you have provided.

(a) To calculate the molecular weight of compound X, we first need to convert the vapor density (3.53 grams per liter) to molar mass. The vapor density is the mass of one mole of the compound divided by the volume it occupies at a specific temperature and pressure.

The molar mass can be calculated using the equation: Molar Mass = Vapor Density * (22.4 L/mol)

In this case, the vapor density is given as 3.53 grams per liter. Therefore, the molar mass of compound X can be calculated as:

Molar Mass = 3.53 g/L * 22.4 L/mol = 78.992 g/mol

So, the molecular weight of compound X is approximately 78.992 g/mol.

(b) To determine the mass of element Q contained in 1.00 mole of each of the three compounds, we can use the percent by weight of element Q in each compound.

For compound X, the percent by weight of element Q is given as 64.8%. Therefore, the mass of element Q in 1.00 mole of compound X can be calculated as:

Mass of Element Q in Compound X = 64.8% * Molar Mass of Compound X

For compound Y, the percent by weight of element Q is given as 73.0%. Therefore, the mass of element Q in 1.00 mole of compound Y can be calculated in the same way.

For compound Z, the percent by weight of element Q is given as 59.3%. Therefore, the mass of element Q in 1.00 mole of compound Z can be calculated in the same way.

(c) To calculate the most probable value of the atomic weight of element Q, we need additional information. The atomic weight of an element is the average weighted mass of its isotopes. We would need the masses of the isotopes of element Q and their abundances to calculate its atomic weight.

(d) To determine the most probable molecular formula of compound Z, we need to analyze the information given about the products of its oxidation.

From the given data, 1.00 gram of compound Z produced 1.37 grams of CO2 and 0.281 gram of water. We can use these mass values to calculate the moles of carbon and hydrogen in compound Z.

Moles of Carbon = Mass of CO2 / Molar Mass of CO2
Moles of Hydrogen = Mass of Water / Molar Mass of Water

Once we have the moles of carbon and hydrogen, we can then calculate the moles of element Q by subtracting the moles of carbon and hydrogen from the total moles of compound Z.

Since we have the moles of each element, we can find the empirical formula by dividing the moles of each element by their lowest common multiple.

For example, if the moles of carbon are 0.100 and the moles of element Q are 0.150, we can divide both values by 0.050 (their lowest common multiple) to get the empirical formula ratio of 2:3. Therefore, the most probable empirical formula of compound Z would be Q2C3H2O.

Please note that the most probable molecular formula may differ from the empirical formula due to the presence of multiple atoms of each element within the molecule.