# chemistry

1.)Calculate the number of moles in
3.50 x 10^21 atoms of silver. Show all work.

2.) Calculate the number of atoms in 2.58 mol antimony. Show all work

3.) Determine the mass of 1.45 mol FePO4. Show all work.

4.) Calculate the number of mol in 6.75 g of NaCl. Show all work.

5.) What is the volume, in liters, of 2.54 mol methane (CH4) gas? Show all work.

6.) What is the empirical formula of a compound that is 36.2% aluminum and 63.8% sulfur. Show all work.

Thanks so much!!! :)

1. A mol is 6*10^23 of anything, sort of like a dozen is 12 of anything
so
3.50 x 10^21 atoms (1 mol of atoms/6*10^23 atoms)

= (3.5/6) 10^(-2) = .58*10^-2 mol = 5.8 *10^-3 = .0058 moles

posted by Damon
2. Now with that information and knowing that a mole of any chemical weighs its gram molecular mass I think you can do the rest
for example a mol of water, H2O has mass
2 H + O = 2(1) + 16 = 18 grams
so for water
18 grams is 6*10^23 molecules is one mole

posted by Damon
3. 4. mols = grams/molar mass

5. At what pressure? If you mean standard pressure of 760 mm Hg then you need to remember that 1 mol of gas occupies 22.4 L at STP

6. Take a 100 g sample which will be
36.2g Al
63.8g S.
Convert these to mols by mols = g/atomic mass.

Find the ratio. The easy way to do that is to divide both numbers by the smaller number. This makes the smaller number of the two exactly 1.0.
Al = 1.24/1.24--This is to get qet 1.00
S = 2/1.34 = 1.49
Obviously, the answer is NOT Al1S1.5 because we want whole numbers. But a 1:1.5 ratio also is 2:3 in whole numbers so the empirical formula is Al2S3.

posted by DrBob222

First Name

## Similar Questions

1. ### Chemistry Help

1.) Calculate the number of atoms in 2.58 mol antimony. 2.) Determine the mass of 1.45 mol FePO4. 3.) Calculate the number of mol in 6.75 g of NaCl. 4.) What is the volume, in liters, of 2.54 mol methane (CH4) gas?. 5.) What is
2. ### chem

calculate the number of oxygen atoms in 0.25 mol fluoroacetic acid (C2H3O2F) show work if possible
3. ### Chemistry

I have realized I don't understand Avagado's number at all My book shows me this diagram instead of just providing a simple formulas that makes no sense at all here is what I have made sense of so far (6.022 x 10^23
4. ### chemistry

calculate number of atoms in 4.67 mol of Ca(NO3)2 I got: 2.81 X 10^24 C atoms or should it be 28.11 x 10^23 C atoms? 5.62 X 10^24 N atoms or should it be 9.34 x 10^23 N atoms? 1.69 x 10^25 O atoms....but are you allowed to do ^25
5. ### chemistry

Calculate the following quantities. (See the periodic table.) (a) mass, in grams, of 2.54 10-2 mol of CdS g (b) number of moles of NH4Cl in 90.0 g of this substance mol (c) number of molecules in 5.081 10-2 mol C6H6 molecules (d)
6. ### Chemistry

A 24.3g sample of a compound XO2 contains 3.365 x 10^23 oxygen atoms. Determine the molar mass in g/mol of the element X. Show your work.
7. ### Chemistry

I donâ€™t know how to do this because I was sick when this was thought. If someone could please explain how to do or set up the first problem. A. Measure out 0.130 moles of salt (NaCl) into a blue, dry cup. You need to convert to
8. ### ap chem

A mole of helium gas contains 6.02x10^23 helium atoms. How many helium atoms are there in a micromole of helium? How many moles of helium does 1.25x10^20 atoms of helium represent? ~I have no idea how to start or what the value of
9. ### Chemistry

Calculate the number of atoms in 2.58 mol antimony. Its an example problem, I need help!
10. ### science

A 24.3g sample of a compoud XO2 contains 3.365 x 10^23 oxygen atoms. Determine the molar mass in g/mol of the element X. Show your work.

More Similar Questions