What mass of water has 6.70 x10^23 molecules?
I keep getting 2.005e47 On my calculator but the answer key says 20 g .
6.70x10^23 molecuels *1 mol/6.02x10^23*18.02 g H2O /1 mol
That's how I set it up.
nah, 10^23/10^23 = 1
perhaps write it as
(6.70/6.02)(10^23/10^23) * 18.02
Well, it seems like your calculation got a bit too heavy on the water molecules! It looks like you forgot to consider the Avogadro's constant in the equation. Let's do the math again, with a bit of twisted humor, shall we?
First, we start with 6.70 x 10^23 molecules of water, which is a big splash of water, I must say. Then we divide it by Avogadro's number, 6.02 x 10^23, to convert it to moles. Now we have a cozy little pond!
Next, we need to convert moles to grams, so we multiply by the molar mass of water, which is 18.02 grams per mole. And voila! We get the answer, 20 grams of water.
So, it seems like your calculator took a dive into the deep end, but don't worry, that happens sometimes. Just remember to add a sprinkle of Avogadro's constant next time, and you'll get the right answer!
Your calculations and setup are correct. Let's go through the calculation:
Given:
Number of water molecules = 6.70 x 10^23 molecules
Step 1: Convert the number of water molecules to moles.
6.70 x 10^23 molecules * (1 mol / 6.02 x 10^23 molecules) = 1.112 mol
Step 2: Convert moles to grams using the molar mass of water.
1.112 mol * (18.02 g H2O / 1 mol) = 20.02104 g
When rounded to the appropriate number of significant figures, the mass of water is approximately 20 g. Your calculated answer of 2.005 x 10^47 g seems to be an error, and the correct answer is indeed 20 g as stated in the answer key.
To calculate the mass of water with 6.70x10^23 molecules, you can use the following steps:
Step 1: Start with the given number of water molecules: 6.70x10^23 molecules.
Step 2: Convert the number of molecules to moles by using Avogadro's number (6.02x10^23 molecules/mol):
6.70x10^23 molecules × (1 mol/6.02x10^23 molecules) = 1.11 mol
Step 3: Use the molar mass of water (H2O), which is approximately 18.02 g/mol, to convert from moles to grams:
1.11 mol × (18.02 g H2O/1 mol) = 19.99 g
Rounded to two decimal places, the mass of water with 6.70x10^23 molecules is approximately 20 g. Therefore, your answer key is correct.