Use the following information to identify element A and compound B, then answer questions a and b.
An empty glass container has a mass of 658.572 g. It has a mass of 659.452 g after it has been filled with nitrogen gas at a pressure of 790 torr and a temperature of 15 C. When the container is evacuated and refilled with a certain element (A) ata pressure of 745 torr and a temperature of 26 C, it has a mass of 660.59 g.
Compound B, a gaseous organic compound that consists of 85.6% carbon and 14.4% hydrogen by mass, is placed in a stainless steel vessel (10.68L) with excess oxygen gas. The vessel is placed in a constant temperature bath at 22 C. The pressure in the vessel is 11.98 atm. In the bottom of the vessel is a container that is packed with Ascarit and a desiccant. Ascarite is abestos impregnated with sodium hydroxide; it quantitatively absorbs carbon dioxide:
2NaOH + CO2 => Na2CO2 + H2O
The desiccant is anhydrous magnesium perchlorate, which quantitatively absorbs the water produced by the combustion reaction as well as the water produced by the above reaction. Neither the Ascarite nor the desiccant reacts with compound B or the oxygen. The total mass of the container with the Ascarite and desiccant is 765.3 g.
The combustion reaction of compound B is initiated by a spark. The pressure immediately rises, then begins to decrease, and finally reaches a steady value of 6.02 atm. The stainless steel vessel is carefully opened, and the mass of the container inside the vessel is found to be 846.7 g.
A and B react quantitatively in a 1:1 mole ratio to form one mole of the single product, gas C.
a. How many grams of C will be produced if 10.0L of A and 8.60L of B (each at STP) are reacted by opening a stopcok connecting the two samples.
b. What will be the total pressure in the system?
Please put the subject (science) you need help with in the subject area.
To identify element A and compound B, we need to analyze the given information and perform calculations.
For element A:
1. Start by noting the mass of the empty glass container (658.572 g).
2. After filling the container with nitrogen gas at a pressure of 790 torr and a temperature of 15°C, the mass increases to 659.452 g.
3. Next, the container is evacuated and refilled with a certain element (A) at a pressure of 745 torr and a temperature of 26°C. The new mass is 660.59 g.
To identify element A, we need to calculate the change in mass and compare it to the molar mass of possible elements. The change in mass is due to the mass of element A that has been added.
Change in mass = Mass after filling with A - Mass after filling with nitrogen
Change in mass = 660.59 g - 659.452 g = 1.138 g
Now, we convert the change in mass to moles using the molar mass:
Molar mass of element A = Change in mass / Moles of A
Assuming no molar mass changes due to temperature and pressure differences, we compare the calculated molar mass (in g/mol) to find the closest match to a known element.
For compound B:
1. We know that compound B consists of 85.6% carbon and 14.4% hydrogen. This information allows us to determine the empirical formula of compound B by assuming we have 100g of the compound.
- Carbon mass = 85.6g
- Hydrogen mass = 14.4g
2. To determine the empirical formula, we need to convert the masses to moles:
- Moles of carbon = Carbon mass / Molar mass of carbon
- Moles of hydrogen = Hydrogen mass / Molar mass of hydrogen
3. Next, we need to find the simplest whole number ratio of carbon to hydrogen atoms by dividing the number of moles by the smallest number of moles calculated in step 2.
4. Finally, we can determine the molecular formula of compound B by multiplying the empirical formula by the appropriate factor to match the molecular mass.
Now let's move on to answering questions a and b:
a. To calculate the grams of compound C produced when 10.0L of A and 8.60L of B (each at STP) react, we need to determine the limiting reactant.
First, convert the given volumes to moles using the ideal gas law at STP:
Moles of A = Volume of A (in L) × (1 mol/ 22.4 L)
Moles of B = Volume of B (in L) × (1 mol/ 22.4 L)
Since the reaction between A and B occurs in a 1:1 mole ratio, we compare the number of moles of A and B. The limiting reactant is the one with fewer moles, as it will determine the maximum possible product.
Let's assume the limiting reactant is A (moles of A < moles of B). Then, we can calculate the moles of C produced by using the mole ratio:
Moles of C = Moles of A
Lastly, convert moles of C to grams using the molar mass of C:
Grams of C = Moles of C × Molar mass of C
b. To find the total pressure in the system during the reaction, we need to consider the ideal gas law:
PV = nRT
Where:
P = pressure (unknown)
V = total volume of the system (combined volumes of A and B)
n = total moles of gas in the system (moles of A + moles of B)
R = ideal gas constant (0.0821 L · atm/(mol · K))
T = temperature (STP = 273 K)
Rearrange the equation to solve for pressure (P):
P = (nRT) / V
Substitute the known values (moles of A and B, V = sum of their volumes) and calculate the total pressure in the system.