Zn metal was allowed to react with hydrochloric acid to produce hyrdogen gas.This gave a total of 555mL of gas collected over water at 20C and a pressure of 747mm of Hg. How many moles of hydrogen were collected? The vapor pressure of water at 20C is 18mm Hg.

Well, first let's convert the pressure of hydrogen gas into the standard unit of pressure, which is atmospheres. To do that, we can use the conversion factor: 1 atm = 760 mmHg.

So, the pressure of hydrogen gas in atmospheres can be calculated as follows:
747 mmHg * (1 atm / 760 mmHg) = 0.9825 atm

Now that we have the pressure in the correct unit, we can use the ideal gas law to calculate the number of moles of hydrogen gas collected. The ideal gas law is given by the formula: PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the ideal gas constant, and T is the temperature in Kelvin.

However, we need to take into account the vapor pressure of water at 20°C (293 K).

The effective pressure of hydrogen gas is given by:
Effective Pressure = Total Pressure - Vapor Pressure

Effective Pressure = 0.9825 atm - 0.0237 atm (calculated as 18 mmHg * (1 atm / 760 mmHg))

Now we have the effective pressure, which is 0.9588 atm. Let's plug this value, along with the known values of volume, temperature, and R, into the ideal gas law to solve for the number of moles (n):

n = PV / RT

n = (0.9588 atm * 0.555 L) / (0.0821 L·atm/mol·K * 293 K)

Simplifying the equation, we find that:

n ≈ 0.021 moles

So, approximately 0.021 moles of hydrogen gas were collected. I hope that's enough mole-larity for you!

To find the number of moles of hydrogen collected, we need to use the ideal gas law equation: PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature in Kelvin.

First, let's convert the given temperatures to Kelvin:
20°C + 273.15°C = 293.15 K

Now, we need to subtract the vapor pressure of water from the total pressure to get the pressure of the hydrogen gas alone:
747 mmHg - 18 mmHg = 729 mmHg

Next, we need to convert the pressure from mmHg to atm, as the ideal gas constant is in units of atm:
729 mmHg / 760 mmHg/atm = 0.9592 atm

We also need to convert the volume of gas collected to liters:
555 mL = 0.555 L

Now we can plug these values into the ideal gas law equation:
0.9592 atm * 0.555 L = n * 0.0821 L·atm/mol·K * 293.15 K

Simplifying the equation:
0.53287 = n * 24.093015

Finally, solving for n:
n = 0.53287 / 24.093015
n ≈ 0.0221 moles

Therefore, approximately 0.0221 moles of hydrogen gas were collected.

To calculate the number of moles of hydrogen gas collected, we need to use the ideal gas law equation:

PV = nRT

Where:
P = pressure of the gas
V = volume of the gas
n = number of moles of the gas
R = ideal gas constant (0.0821 L.atm/mol.K)
T = temperature in Kelvin

First, we need to convert the given temperature from degrees Celsius to Kelvin:
T(K) = T(°C) + 273.15
T(K) = 20 + 273.15
T(K) = 293.15 K

Next, we need to account for the vapor pressure of water. The total pressure of the gas collected is the sum of the pressure of hydrogen gas and the vapor pressure of water:
Total pressure = Pressure of hydrogen + Vapor pressure of water
Total pressure = 747 mmHg + 18 mmHg
Total pressure = 765 mmHg

Now, we can rearrange the ideal gas law equation to solve for the number of moles of hydrogen gas:

n = PV / RT

Plugging in the values:
n = (765 mmHg) * (555 mL) / (0.0821 L.atm/mol.K * 293.15 K)

First, let's convert the volume from milliliters (mL) to liters (L):
Volume (L) = Volume (mL) / 1000
Volume (L) = 555 mL / 1000
Volume (L) = 0.555 L

n = (765 mmHg) * (0.555 L) / (0.0821 L.atm/mol.K * 293.15 K)

Now, let's simplify the equation:
n = 42.166575 / 24.07065615
n ≈ 1.7529 moles (rounded to four decimal places)

Therefore, approximately 1.7529 moles of hydrogen gas were collected.

PV = nRT

P = (747-18/760) = ?atm
V = 555 mL = 0.555L
R = you know it
T = 20C = 273K
Solve for n.