A chunk of iron weighs 4.32 g.
a) How many iron atoms are there in this sample?
55.85 g Fe = 1.00 mol Fe = 6.022 x 1023 atoms Fe
mols Fe = grams Fe/55.85
Then mols Fe x 6.022E23 = ? no. atoms.
b) How many moles of iron are there in this sample?
See above.
2. . You have a copper bar weighing 71.24 g and a silver disk weighing 98.50 g. Which sample has the greater number of atoms, and how many more atoms are there in the one than the other?
mols Cu = grams Cu/atomic mass Cu=?
Then mols Cu x 6.022E23 = number Cu atoms. Compare with other answer and subtract.
3. a)How many moles of compound are present in 221 g of ammonium chloride, NH4Cl?
mols = grams NH4Cl/molar mass NH4Cl = ?
b)How many moles of hydrogen are in this sample?
There are 4 mols H in each mol NH4Cl; therefore, there are 4x mols NH4Cl of H
can some one help me with a few chem questions please.
A chunk of iron weighs 4.32 g.
a) How many iron atoms are there in this sample?
55.85 g Fe = 1.00 mol Fe = 6.022 x 1023 atoms Fe
b) How many moles of iron are there in this sample?
2. . You have a copper bar weighing 71.24 g and a silver disk weighing 98.50 g. Which sample has the greater number of atoms, and how many more atoms are there in the one than the other?
3. a)How many moles of compound are present in 221 g of ammonium chloride, NH4Cl?
b)How many moles of hydrogen are in this sample?
4 answers
1. i do not understand your explaination.
2. i do not understand explaination.
3. a i don't understand, so b is 16?
2. i do not understand explaination.
3. a i don't understand, so b is 16?
OK, so I'll start over. Below I have erased all I wrote but kept what you wrote. My response is in bold.
A chunk of iron weighs 4.32 g.
a) How many iron atoms are there in this sample?
55.85 g Fe = 1.00 mol Fe = 6.022 x 1023 atoms Fe
What you have written is exactly right. 55.85 is the atomic mass Fe, 55.85 grams is 1 mol Fe and there are 6.022E23 atoms in 1 mol. So how many mols Fe are there in 4.32 g Fe? I wrote that mols Fe = grams atomic mass so 4.32/55.85 = approx 0.078 mols (but you need to do it more accurately). If there are 6.022E23 atoms in 1 mol then there must be approx 0.078 x 6.022E23 = ? atoms in 0.078 mols. Again, you need to do it more accurately.
b) How many moles of iron are there in this sample?
I calculate the mols Fe in that 4.32 sample above.
2. . You have a copper bar weighing 71.24 g and a silver disk weighing 98.50 g. Which sample has the greater number of atoms, and how many more atoms are there in the one than the other?
You calculate the mol Cu (same process as above) in the 71.23 g Cu and calculate atoms Cu in that many mols (again, same process as above), then compare atoms Cu in 2 with atoms Fe in 1 to see which is larger, then subtract the larger number from the smaller number to find the difference.
3. a)How many moles of compound are present in 221 g of ammonium chloride, NH4Cl?
From above, mols = grams/molar mass; therefore, in 221 g NH4Cl you will have 221/approx 53.5 = approx 4 mols NH4Cl.
b)How many moles of hydrogen are in this sample?
There are approx 4 mols NH4Cl. You have 4 mols H atoms for every mol of NH4Cl; therefore, there must be approx 4 x 4 = approx 16. The number isn't exactly 16; I obtained 4.13 mols NH4Cl so you will have 4 x 4.13 = 16.5 mols H atoms.
Anna Friday, November 13, 2015 at 1:28pm
1. i do not understand your explaination.
2. i do not understand explaination.
3. a i don't understand, so b is 16?
A chunk of iron weighs 4.32 g.
a) How many iron atoms are there in this sample?
55.85 g Fe = 1.00 mol Fe = 6.022 x 1023 atoms Fe
What you have written is exactly right. 55.85 is the atomic mass Fe, 55.85 grams is 1 mol Fe and there are 6.022E23 atoms in 1 mol. So how many mols Fe are there in 4.32 g Fe? I wrote that mols Fe = grams atomic mass so 4.32/55.85 = approx 0.078 mols (but you need to do it more accurately). If there are 6.022E23 atoms in 1 mol then there must be approx 0.078 x 6.022E23 = ? atoms in 0.078 mols. Again, you need to do it more accurately.
b) How many moles of iron are there in this sample?
I calculate the mols Fe in that 4.32 sample above.
2. . You have a copper bar weighing 71.24 g and a silver disk weighing 98.50 g. Which sample has the greater number of atoms, and how many more atoms are there in the one than the other?
You calculate the mol Cu (same process as above) in the 71.23 g Cu and calculate atoms Cu in that many mols (again, same process as above), then compare atoms Cu in 2 with atoms Fe in 1 to see which is larger, then subtract the larger number from the smaller number to find the difference.
3. a)How many moles of compound are present in 221 g of ammonium chloride, NH4Cl?
From above, mols = grams/molar mass; therefore, in 221 g NH4Cl you will have 221/approx 53.5 = approx 4 mols NH4Cl.
b)How many moles of hydrogen are in this sample?
There are approx 4 mols NH4Cl. You have 4 mols H atoms for every mol of NH4Cl; therefore, there must be approx 4 x 4 = approx 16. The number isn't exactly 16; I obtained 4.13 mols NH4Cl so you will have 4 x 4.13 = 16.5 mols H atoms.
Anna Friday, November 13, 2015 at 1:28pm
1. i do not understand your explaination.
2. i do not understand explaination.
3. a i don't understand, so b is 16?
number 1a is 4.66x10^23, atoms Fe
number 1b is .0774mol Fe
number 2 is 1.25x10^23 more atoms of
copper
number 3a is 4.13 mol ammonium chloride
number 3b is 16.52 mol H
number 1b is .0774mol Fe
number 2 is 1.25x10^23 more atoms of
copper
number 3a is 4.13 mol ammonium chloride
number 3b is 16.52 mol H
1 answer