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1. Calculate the mass of 6.022 × 1023 molecule of Calcium carbonate (CaCO3).

2. Calculate the mass of 12.044 × 1023 carbon atoms.

3. Calculate the number of oxygen atoms in 1 mole of O2.

4. Calculate the number of Cu atoms in 0.635g of Cu.

5. Calculate the number of molecules in 11.2 liters of SO2 gas at NTP.

6. An atom of some element X weighs 6.644 × 10-23 g. Calculate the number of gram-atoms in 40 kg of it.

7. An atom of some element X weighs 6.644 × 10-23 g. Calculate the number of gram-atoms in 40 kg of it.

8. Calculate the mass of 5 moles of CaCO3 in g.

9. Calculate the number of oxygen atoms in 0.2 mole of Na2CO3.10H2O.

10. What is the percent composition of all elements of glucose, C6H12O6?


Sagot :

Answer:

1. 100 g.

2. 24 g.

3. 12.044 ×1023 oxygen atoms.

4. 6.022 * 10^21

5. 3.011 × 10^23 molecules.

6. 1000

7. 1000

8. 500g

9. 1.566 X 10^24

10.40%, 6.66% and 53.33%.

Explaination:

1. CaCO3 = 40+12+3×16 = 100 g

No. of moles of CaCO3 = No.ofmolecules/Avogadro constant = 6.022 × 1023/ 6.022 × 1023 = 1

mole Mass of CaCO3 = No. of moles × molar mass = 1 × 100 g = 100 g.

2. of atoms/Avogadro constant = 12.044 × 1023/6.022 × 1023 = 2

mole Mass of carbon atoms = No. of moles × atomic mass = 2 × 12 = 24 g.

3. Solution — 1 molecule of O2 = 2 oxygen atoms So, 1 mole of O2 = 2 mole oxygen atoms = 2 × 6.022 × 1023 = 12.044 ×1023 oxygen atoms.

4.The atomic mass of Copper ( Cu ) is 63.5 u . There fore , the molar mass of Copper is 63.5 g . So , 63.5 g of Cu will contain 6.022 * 10^23 . So , 0.635 g of Cu will contain 6.022 * 10^23 / 100 = 6.022 * 10^21

5.Hence, 11.2 liters of SO2 gas at NTP contains 3.011 × 10^23 molecules.

6.Atomic mass of the element =Massofoneatom×6.02×10²³

=6.644×10

−23

×6.02×10

23

=40g

No. of gram atoms = No.ofgram

MMassoftheelementingram

= 40

40000

=1000

7. seym lang sa number

9. there are 1.566 X 10^24 atoms of oxygen in 0.2 moles of Na2CO3. 10H2O

10. elements present in are C, Oxygen and H. The atomic mass of Carbon, Hydrogen and Oxygen are 12,1 and 16. The percentage of composition of C, H and O in glucose is 40%, 6.66% and 53.33%.

#:correct me if I'm wrong