The mass of 5.15 × 10²¹ atoms of chromium is 0.44 g
From Avogadro's hypothesis,
6.02×10²³ atoms = 1 mole of Cr
But:
1 mole of Cr = 52 g
Thus, we can say that:
6.02×10²³ atoms = 52 g of Cr
With the above information, we can obtain the mass of 5.15 × 10²¹ atoms of chromium. This can be obtained as follow:
6.02×10²³ atoms = 52 g of Cr
Therefore,
5.15×10²¹ atoms = (5.15×10²¹ × 52) / 6.02×10²³
5.15×10²¹ atoms = 0.44 g of Cr
Thus, the mass of 5.15 × 10²¹ atoms of chromium is 0.44 g
Learn more: brainly.com/question/15488332
Answer:
D) 3.51x10²³ formula units
Explanation:
To know this, we need to calculate the molecular mass of CaO. To do that, let's use the atomic mass of each element of this compound.
Ca: 40.08 g/mol; O: 16 g/mol
With these given AM, let's calculate the molar mass of CaO:
Mm CaO = 40.08 + 16 = 56.08 g/mol
Now that we have the MM of CaO, it's time to determine the moles of CaO:
moles = mass / MM
moles = 32.7 / 56.08 = 0.5831 moles
Finally to get the formula units, we need to use the Avogadro's number which is 6.02x10²³. According to this number, 1 mole of any substance has this number of atoms, molecules or formula units. So, if we have 0.5831 moles, then the formula units will be:
FU = 0.5831 * 6.02x10²³
<h2>
FU = 3.51x10²³ formula units</h2>
Hope this helps
Because neither can be created or destroyed
Answer: 55.56 moles of MgO
Explanation:
1 mole = avogadro number
if 6.21x10^25 atoms then molecules of MgO (equal numbers of Mg and O atoms)
= 0.5*6.21x10^25 = 3.105 molecules of MgO
So moles of MgO = 0.5*6.21*10^25/avogadro number = 55.56
I don't know how well known/accepted this is (it's in my textbook so I'm guessing it's right), but Sulphur has two forms - the alpha and beta forms ,apparently gamma sulphur exists as well.
The alpha form is rhombic, yellow in color and has a MP of 385.8 K. The beta form is colorless and has a MP of 393 K and is formed by melting rhombic sulphur and cooling it till a crust forms on top. Poke a hole and pour out the liquid inside and you get beta sulphur. The transition point is 369K - below it, alpha sulphur is stable and above it, beta sulphur is stable. Both have helped. I had to pull out an old textbook and that's something that I don't usually do.
