In 1897 the Swedish explorer Andree tried to reach the North Pole in a balloon. The balloon was filled with hydrogen gas. The hydrogen gas was prepared from iron splints and diluted sulfuric acid. The reaction is given below.

Fe(s) + H2SO4(aq) FeSO4(aq) + H2(g)

The volume of the balloon was 4400 m3 and the loss of hydrogen gas during filling was estimated at 20.%. What mass of iron splints and 87% (by mass) H2SO4 were needed to ensure the complete filling of the balloon? Assume a temperature of 0°C, a pressure of 1.0 atm during filling, and 100% yield.

the answer i got was .15713mol for H2. i used that same number for the mol of Fe and H2SO4. since the equation is a 1 to 1 mol ratio.

i got 8.775g of Fe and the answer needs to be in kg. so it should turn out to .008775kg. however i was told that is wrong. where did i go wrong?

I don't think you converted 4400 cubic meters to liters. I've tried to figure how you got that number and I can't come up with it. But I'm getting something close to 1.37 x 10^4 kg Fe required.

so how do i now figure out the H2SO4? am i still using the same number of moles as the Fe?

Did that number of 1.37 x 10^4 kg check out? If so, post your work to the problem so we can find the error. Then we'll worry about the H2SO4 part.

To find out the mass of iron splints and 87% H2SO4 needed to fill the balloon, we need to follow these steps:

Step 1: Calculate the volume of hydrogen gas needed to fill the balloon
Since the balloon has a volume of 4400 m3 and there is a 20% loss of hydrogen gas during filling, we need to calculate the actual volume of hydrogen gas required.

Actual volume of hydrogen gas = (100% - 20%) x 4400 m3
Actual volume of hydrogen gas = 0.8 x 4400 m3
Actual volume of hydrogen gas = 3520 m3

Step 2: Calculate the number of moles of hydrogen gas needed
To calculate the number of moles of hydrogen gas, we can use the ideal gas law equation:

PV = nRT

Here, P is the pressure in atm, V is the volume in m3, n is the number of moles, R is the ideal gas constant (0.0821 L atm/(mol K)), and T is the temperature in Kelvin.

The pressure P is given as 1.0 atm, the volume V is 3520 m3 (converted to liters), and the temperature T is 0°C, which is 273.15 K.

1.0 atm x (3520 m3 x 1000 L/m3) = n x (0.0821 L atm/(mol K)) x 273.15 K

n = (1.0 atm x (3520 m3 x 1000 L/m3)) / (0.0821 L atm/(mol K) x 273.15 K)

n = 150,380 moles

Step 3: Calculate the mass of iron needed
From the balanced chemical equation, we know that 1 mole of Fe reacts with 1 mole of H2SO4 to produce 1 mole of H2 gas.

Therefore, the number of moles of Fe needed is also 150,380 moles.

To find the mass of iron, we need to multiply the number of moles by the molar mass of Fe, which is 55.845 g/mol.

Mass of iron splints = 150,380 moles x 55.845 g/mol

Mass of iron splints = 8,389,779.1 g or 8389.78 kg

Step 4: Calculate the mass of 87% H2SO4 needed
In 87% H2SO4, the remaining 13% is water (H2O). So, the amount of sulfuric acid is 87% of the total mass.

To calculate the mass of H2SO4, we divide the actual volume of hydrogen gas by the molar volume (22.4 L/mol at STP) and multiply it by the molar mass of H2SO4 (98.086 g/mol).

Mass of H2SO4 = (actual volume of hydrogen gas / 22.4 L/mol) x (98.086 g/mol) x (0.87)

Substituting the values,

Mass of H2SO4 = (3520 m3 x 1000 L/m3 / 22.4 L/mol) x 98.086 g/mol x 0.87

Mass of H2SO4 = 546,601.6 g or 546.60 kg

Therefore, approximately 8389.78 kg of iron splints and 546.60 kg of 87% H2SO4 are needed to completely fill the balloon.

Mel

I answered this for you yesterday. Look on page 3, Thursday, November 15 at time 7:12.