The question says:

A sample of helium is collected by displacing 182 mL of water. The pressures of the gas and the atmosphere are equalized, using the method described in this experiment. The atmospheric pressure is 738 mmHg. The temperature of the water and that of the gas are identical at 26 C. How many moles of helium have evolved?

I know I need to use PV=nRT, but I want to make sure I'm plugging in the correct parts.
Would the pressure of the He also be 738 mmHg because it is equalized?
And is the volume of He also 182 mL because it displaced that volume of water?

Well, it seems like you've got the right formula in mind! However, I have to warn you that my knowledge of science is a bit... inflated, to say the least. But fear not! I shall attempt to assist you nonetheless.

Now, when it comes to the pressure of the helium, think of it like this: the pressure of the gas and the atmosphere are equalized, so the pressure of the helium would indeed be 738 mmHg. Great job!

As for the volume of the helium, it may not be exactly the same as the volume of water displaced. You see, the water is just there to give us a way of measuring the volume of the helium. So, in this case, the volume of the helium would actually be the volume of the water displaced, which is 182 mL.

Now, we can plug these numbers into the formula PV = nRT and solve for n, the number of moles of helium.

But remember, I'm just a clown bot, so double-check my calculations before you hand in your homework. Good luck, and may the helium be with you!

You are on the right track! In this problem, the pressure of the helium gas will indeed be equal to the atmospheric pressure of 738 mmHg since they have been equalized.

However, the volume of the helium gas will not be equal to the volume of water displaced (182 mL). The volume of the helium gas can be determined using the ideal gas law equation, PV = nRT.

Let's break down the information given in the question step-by-step:

1. Pressure of the helium gas: 738 mmHg
2. Volume of the helium gas: Unknown (Let's call it V)
3. Moles of the helium gas: Unknown (Let's call it n)
4. Gas constant: R = 0.0821 L·atm/(mol·K) (Remember to use the appropriate unit depending on the units used for pressure, volume, and temperature.)
5. Temperature of the gas (and water): 26°C = 26 + 273 = 299 K

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

PV = nRT

n = (PV) / (RT)

Substituting the given values, we have:

n = (738 mmHg) x (V mL) / [(0.0821 L·atm/(mol·K)) x (299 K)]

Since the given volume of the water displaced is in mL, we need to convert it to liters to maintain consistent units in the calculation:

V = 182 mL = 0.182 L

Plugging in this value and solving the equation:

n = (738 mmHg) x (0.182 L) / [(0.0821 L·atm/(mol·K)) x (299 K)]

Now you can calculate the number of moles of helium that have evolved.

To find the number of moles of helium evolved, you can indeed 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 this case, the pressure of the gas and the atmosphere are equalized, so the pressure of the helium gas is indeed 738 mmHg.

However, the volume of the helium gas is not equal to the volume of water displaced. When the water is displaced, it creates a vacuum in the container, allowing the helium gas to expand and fill the entire volume. Therefore, the volume of helium is not 182 mL.

To determine the volume of the helium gas, you need to consider the conditions mentioned in the problem statement. It states that the temperature of the water and the gas are identical at 26°C. Since the temperature is the same, you can calculate the volume of the helium gas using the volume of water displaced.

To calculate the volume of the helium gas, you need to convert the volume of water from milliliters (mL) to liters (L) since the unit of volume in the Ideal Gas Law equation is in liters. 1 mL is equivalent to 0.001 L.

The volume of water displaced is given as 182 mL, so you convert it to liters by multiplying 182 mL by 0.001 L/mL:

Volume of water displaced = 182 mL × 0.001 L/mL = 0.182 L

Now that you have the volume of water displaced, you can use it as the volume (V) in the Ideal Gas Law equation to find the number of moles of helium (n). Keep in mind to convert the temperature from Celsius (°C) to Kelvin (K) since the unit of temperature in the Ideal Gas Law equation is in Kelvin. To convert from Celsius to Kelvin, you add 273.15 to the Celsius temperature.

So, the equation becomes:

738 mmHg × V = nRT

738 mmHg × 0.182 L = n × (0.0821 L·atm/(mol·K)) × (26°C + 273.15)

Now you can solve for n, the number of moles of helium evolved.

bkj