Calculate the number of hydrogen molecules formed when 5.6 mL of ammonia at STP is decomposed by the following reaction:

Question

Calculate the number of hydrogen molecules formed when 5.6 mL of ammonia at STP is decomposed by the following reaction:

___NH3 „³ ___ N2 + ___ H2

Answer 1

ammonia gas?

You will have to know the temp,pressure to convert that volume to moles, then to molecules.

Recommend balance the equation first.

Answer 2

You have 5.6 mL of NH3.

There are 22.4 L per mole of gas at STP.

So 5.6e-3 / 22.4 mole of NH3.

Balance the equation to determine the corresponding number of H2.

Answer 3

Correct, Graham, I missed the STP statement.

Answer 4

To calculate the number of hydrogen molecules formed when ammonia (NH3) is decomposed, we need to use the balanced chemical equation for the reaction and the ideal gas law.

The balanced equation for the reaction is:

NH3 → N2 + 3H2

From the equation, we can see that for every 1 mole of ammonia (NH3) decomposed, we get 3 moles of hydrogen gas (H2).

To find the number of moles of ammonia, we can use the ideal gas law equation:

PV = nRT

Where:
P = pressure (at STP, pressure is 1 atm)
V = volume of ammonia
n = number of moles of ammonia
R = ideal gas constant (0.0821 L.atm/mol.K)
T = temperature (at STP, temperature is 273 K)

Given:
Volume of ammonia (V) = 5.6 mL (or 0.0056 L)

First, we need to convert the volume of ammonia to moles using the ideal gas law equation. Rearranging the equation to solve for n:

n = PV / RT

n = (1 atm) * (0.0056 L) / (0.0821 L.atm/mol.K * 273 K)

n ≈ 0.0002496 mol (approximately)

Since the balanced equation tells us that for every 1 mole of ammonia decomposed, 3 moles of hydrogen gas are formed:

The number of moles of hydrogen gas formed = 3 * (number of moles of ammonia decomposed)
= 3 * 0.0002496 mol
= 0.0007488 mol

Finally, to convert the number of moles to the number of hydrogen molecules, we need to use Avogadro's number, 6.022 x 10^23 molecules/mol:

Number of hydrogen molecules = (number of moles of hydrogen gas formed) * (Avogadro's number)
= 0.0007488 mol * (6.022 x 10^23 molecules/mol)
≈ 4.507 x 10^20 molecules

Therefore, approximately 4.507 x 10^20 hydrogen molecules are formed when 5.6 mL of ammonia at STP is decomposed.