Question

1. A sample of gold (Au) has a mass of 35.12 g.
a. Calculate the number of moles of gold (Au) in the sample and record in Table 1. Show your work.
b. Calculate the number of atoms of gold (Au) in the sample and record in Table 1. Show your work.
2. A sample of table sugar (sucrose, C12H22O11) has a mass of 1.202 g.
a. Calculate the number of moles of C12H22O11 contained in the sample and record in Table 1. Show your work.
b. Calculate the moles of each element in C12H22O11and record in Table 1. Show your work.
c. Calculate the number of atoms of each type in C12H22O11 and record in Table

Answer 1

Stoichiometry (ANY HELP WOULD BE APPRECIATED

My answers were
1a. I got 35.12 x 1mol/196.97g= 0.1783 mol (For this question if they meant the molar mass I got 197 g/mol

1b. 1.83 x 10^23 atoms AU. I also got (6.022 x 10^23) x 0.1783 moles= 1.074 x 10^23 atoms.

2a. 1 mole C12H22O11= 342.295g/mol because (1moleC12=144.132g, 1moleH22=22.1738g, 1moleO11=175.989g, and 1moleC12H22O11=342.295g

2b For this I got two possible answers
C: 0035moles×12=0.042molesC
H: 0035moles×22=0.077molesH
O: .0035moles×11=0.386molesO
OR
C: 0.03494 mol
H: 0.06406 mol
O: 0.03203 mol

2c. For this question I got
C: 2.10 x 1022
H: 3.86 x 1022
O: 1.93 x 1022


Any help would be appreciated. I'm checking my answers.

Answer 2

1a & 1b (0.1783 mol and 1.074 x 10^23 atoms) are correct. I don't know what the 1.83 x 10^23 atoms AU is.

Answer 3

It seems that you have 0.0035 mol C12H22O11. You are missing significant digits.

Answer 4

I'm not sure why you think there are multiple possible answers for these questions. There are, but there is only one correct answer :-)

When a problem asks for number of moles, it means mass / molar mass, never molar mass.

35.12 g Au / molar mass of Au = number of moles of Au

number of moles of Au * Avogadro number = number of atoms of Au

molar mass of sucrose = 12 * molar mass of C + 22 * molar mass of H + 11 * molar mass of O

1.202 g sucrose / molar mass of sucrose = moles of sucrose

moles of element / moles of sucrose = number of atoms of element/mole sucrose

moles of element = number of atoms of element in sucrose/mole sucrose * moles of sucrose

number of atoms of element = moles of element * Avogadro number

Your numbers of atoms for 2c are all incorrect because you used your incorrect answers for 2b to compute them. If you had shown your work as the problem requests, we could identify what you are doing incorrectly...