1 g alloy of Cu and Zn reacted with excess of H2SO4 gives 60 ml of H2 at STP. What is the % of Zn in the alloy?

60 ml of H2 at STP is .060/22.4 = 0.0268 moles of H2 formed.

Zn will release H2 in sulfuric acid, but Cu will not.

If you have x grams of Zn and 1-x grams of Cu (total = 1.0 g), the Zn reaction will result in x/65.4 moles of H2.

x/65.4 = 0.00268 moles
x = 0.175

The alloy is 17.5% zinc

Well, let's calculate it with a touch of humor, shall we?

So, we have an alloy of Cu and Zn. They walk into a bar and meet their old friend, H2SO4. They have a few rounds of drinks together and things get a little rowdy. In the end, 60 ml of H2 is produced at STP.

Now, to find the percentage of Zn in the alloy, we'll need to do a little math.

Let's assume that the total weight of the alloy is 100 grams (just to make our calculations easier).

Assuming that Zn is X% of the alloy, then Cu would be (100 - X)% of the alloy.

Now, we know that when the alloy reacts with H2SO4, we get 60 ml of H2 at STP. But remember, H2 is a pretty lightweight gas, so its weight can be neglected.

Since 1 mole of any gas occupies 22.4 L at STP, we can calculate the number of moles of H2 that were produced. We'll use the ideal gas law here: PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the ideal gas constant, and T is temperature.

But wait, I promised humor, didn't I?

Okay, here goes:

Why did the H2 go to therapy? Because it had too many "moles" to deal with!

Back to the calculation!

Using the ideal gas law, we find that the number of moles of H2 is 60 ml / 22.4 L/mol ≈ 2.68 × 10^-3 moles.

Now, let's figure out the molar ratios between Zn and H2 in the reaction.

From the balanced chemical equation, we see that for every mole of Zn, we get 1 mole of H2. So, the number of moles of Zn will also be 2.68 × 10^-3 moles.

Now, let's calculate the molar mass of Zn, which is approximately 65.38 g/mol.

The mass of Zn in the alloy will be: 2.68 × 10^-3 moles × 65.38 g/mol ≈ 0.174 grams.

Since our original assumption was that the total weight of the alloy is 100 grams, we can now calculate the percentage of Zn in the alloy:

Percentage of Zn = (0.174 g / 100 g) × 100 ≈ 0.174%.

So, there you have it — the percentage of Zn in the alloy is approximately 0.174%.

I hope I was able to bring a smile to your face and provide some useful information at the same time!

To find the percentage of zinc (Zn) in the alloy, we need to calculate the moles of hydrogen gas (H2) produced and the moles of zinc in the alloy.

First, let's calculate the moles of H2 gas produced.
At STP (Standard Temperature and Pressure), 1 mole of any gas occupies 22.4 liters. Since we have 60 ml of H2 gas, we need to convert it to liters.

1 L = 1000 mL
60 mL = 60/1000 L = 0.06 L

Now, we can calculate the moles of H2 gas produced using the ideal gas law.

PV = nRT

Where:
P = pressure (at STP = 1 atm)
V = volume (in liters)
n = moles
R = ideal gas constant (0.0821 L·atm/mol·K)
T = temperature (at STP = 273 K)

Using the given information:
P = 1 atm
V = 0.06 L
R = 0.0821 L·atm/mol·K
T = 273 K

Plugging in the values:

(1 atm)(0.06 L) = n(0.0821 L·atm/mol·K)(273 K)

Simplifying:

0.06 = n(22.4)

n = 0.06/22.4
n ≈ 0.0027 moles

Now, let's calculate the moles of Zn in the alloy.
From the balanced chemical equation, we know that the reaction is:

Zn + H2SO4 → ZnSO4 + H2

From the equation, we can see that for every 1 mole of Zn, 1 mole of H2 is produced.

Therefore, the number of moles of Zn in the alloy is equal to the number of moles of H2 produced, which is approximately 0.0027 moles.

To find the percentage of Zn in the alloy, we need to compare the moles of Zn to the total moles of the alloy.

Let's assume the alloy has a total mass of 100 grams.

The molar mass of Zn is approximately 65.38 g/mol.

Using the number of moles of Zn (0.0027 moles) and the molar mass of Zn (65.38 g/mol), we can calculate the mass of Zn in the alloy.

Mass of Zn = Number of moles of Zn × Molar mass of Zn
Mass of Zn = 0.0027 mol × 65.38 g/mol
Mass of Zn ≈ 0.1761 g

The percentage of Zn in the alloy can be calculated by dividing the mass of Zn by the total mass of the alloy and multiplying by 100.

% of Zn = (Mass of Zn / Total mass of the alloy) × 100
% of Zn = (0.1761 g / 100 g) × 100
% of Zn ≈ 0.1761%

Therefore, the percentage of Zn in the alloy is approximately 0.1761%.

To determine the percentage of Zn in the alloy, we need to understand the chemical reaction that is taking place. In this case, the alloy of Cu and Zn is reacting with excess H2SO4 to produce hydrogen gas (H2).

The balanced chemical equation for this reaction is as follows:
Cu + Zn + H2SO4 → CuSO4 + ZnSO4 + H2

From the equation, we see that one mole of Zn reacts with one mole of H2SO4 to produce one mole of H2 gas. Since we are given that 60 mL of H2 gas is produced at STP (Standard Temperature and Pressure), we can use the ideal gas law to find the number of moles of H2 gas.

STP conditions are defined as a temperature of 273.15 K (0°C) and a pressure of 1 atmosphere (atm). At these conditions, one mole of any ideal gas occupies a volume of 22.4 liters.

Converting the given volume of H2 gas from mL to liters:
60 mL * (1 L / 1000 mL) = 0.06 L

Using 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, we can rearrange the equation to solve for n (number of moles).

n = PV / RT

Plugging in the values:
n = (1 atm) * (0.06 L) / (0.0821 L·atm/mol·K * 273.15 K)
n ≈ 0.002178 mol

According to the balanced equation, one mole of Zn produces one mole of H2. Hence, the number of moles of Zn in the alloy is also approximately 0.002178 mol.

To calculate the percentage of Zn in the alloy, we need to know the total mass of the alloy. Once we have the mass, we can divide the moles of Zn by the total moles of the alloy and multiply by 100.

For example, if the total mass of the alloy is 10 g, we can calculate the percentage of Zn as follows:

Mass of Zn = (0.002178 mol Zn) * (Atomic Mass of Zn)
Mass of Alloy = (Mass of Cu + Mass of Zn)
% Zn = (Mass of Zn / Mass of Alloy) * 100

By plugging in the values, you will be able to find the percentage of Zn in the alloy.