4. How many moles are in 54.0 grams of Silver?

54.0 g Ag x (108mol ag /1 g ag ) = 5,832 ag moles Ag

(Use the gray boxes to insert the values for the conversion factors.)

5. What is the mass of 6.3 moles of Sulfur?

6.3 mol S x ( / ) = g S

6. How many atoms are in 6.0 moles of Argon?

6.0 mol Ar x ( / ) = atoms of Ar

7. How many moles of Kr are in 112 g of Krypton?

112 g Kr x ( / ) = moles of Kr

8. How many moles are in 1.93 x1024 formula units of KF, potassium fluoride?

1.93 x1024 formula units x ( / ) = mol KF

(The next two problems need 2 step conversions - so there are two conversion factors (fractions) for the problem - remember the mole map - covert to moles first, then to the desired unit.)

9. How many atoms are in 86.2 g of Si (silicon)?

86.2 g Si x ( / ) x ( / ) = atoms of silicon

10. What is the mass in grams of 4.8 x 1024 atoms of Magnesium?

4.8 x 1024 atoms of Mg x ( / ) x ( / ) = g Mg


Sagot :

4. Molar mass of silver m Ms~=108 g/mol
Hence there are n=54*(1/108)=0.5 mols of Silver in 54 grams of Silver.

5. 6.3*(108/1)=680.4g

6. Avogadro's number : Na~=6.022×10^23
6.0*(6.022*10^23/1)=36.132*10^23 atoms

7. Molar mass of Krypton : Mk=84 g/mol
112/84=1.33 moles of Kr

8. 1.93*10^24*(1/(6.022×10^23))=3.2 moles KF

9. Molar mass of Silicon : Ms=28 g/mol
86.2*(1/28)*(6.022×10^23/1)=18.5*10^23 atoms of silicon

10. Molar mass of Magnesium : M1=24 g/mol
4.8*10^24*(1/(6.022×10^23))*(24/1)=191 g Mg