I'm having a little trouble doing a worksheet.
1.25 moles of KBr contains how many Br atoms?
How do I find the number of atoms for one of them?
Also, I'm not sure how to solve:
Calculate the number of atoms in CO2.
Thanks.
Is that 1.25 or the #1 problem that has 0.25 mols. I'll assume it is 1.25 moles.
1 mole KBr contains 6.02 x 10^23 molecules of KBr so there will be 6.02 x 10^23 x 1.25 = ?? molecules of KBr. You can see that each molecule of KBr contains 1 Br ion. Technically, there aren't ANY Br ATOMS but I think the intent of the problem is to solve for Br ions and call those atoms.
How much CO2? 1 kg, 1 mg, 1 rail car? There are 3 atoms per molecule of CO2; 2 atoms of oxygen and 1 atom of C to make 3 atoms total per molecule CO2.
Thank you for answering my question. The atom part in the last part was the only thing that confused me. Much appreciated.
To find the number of Br atoms in 1.25 moles of KBr, you need to use Avogadro's number. Avogadro's number is a constant that represents the number of particles (atoms, molecules, ions) in one mole of a substance, which is approximately 6.022 x 10^23.
Here's how you can solve it step by step:
1. Start by finding the molar mass of KBr. The molar mass of K (potassium) is approximately 39.10 g/mol, and the molar mass of Br (bromine) is approximately 79.90 g/mol. So, the molar mass of KBr is 39.10 + 79.90 = 119.00 g/mol.
2. Use the given amount of moles (1.25 moles) and the molar mass of KBr to find the mass of KBr. Multiply the moles by the molar mass:
1.25 moles * 119.00 g/mol = 148.75 grams.
3. Use the mass of KBr (148.75 grams) to determine the number of KBr molecules by dividing the mass by the molar mass:
148.75 g / 119.00 g/mol = 1.25 moles.
4. Finally, multiply the number of moles by Avogadro's number to get the number of Br atoms:
1.25 moles * (6.022 x 10^23 atoms/mol) = 7.53 x 10^23 Br atoms.
For the second question, you can follow a similar approach to find the number of atoms in CO2:
1. Determine the molar mass of CO2. The molar mass of C (carbon) is approximately 12.01 g/mol, and the molar mass of O (oxygen) is approximately 16.00 g/mol. Therefore, the molar mass of CO2 is 12.01 + (16.00 x 2) = 44.01 g/mol.
2. Divide the given amount by the molar mass to find the number of moles. If no amount is given, assume it to be 1 mole in this case:
1 mole / 44.01 g/mol = 0.0227 moles.
3. Finally, multiply the number of moles by Avogadro's number to obtain the number of CO2 molecules, which will also be the number of atoms in CO2:
0.0227 moles * (6.022 x 10^23 atoms/mol) = 1.37 x 10^22 atoms of CO2.
Remember to always use consistent units and follow the steps carefully to get accurate results.