EXERCISE 8-1 Formula Mass, Moles and Molecules

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1	What is the atomic mass of krypton in g/mol to four significant figures?
		131.3 g/mol
		39.10 g/mol
		167.6 g/mol
		83.80 g/mol
		None of the previous answers.

2	Calculate the number of moles in 4.19 g of krypton.
		351 moles
		20.0 moles
		2.50x10^-2 moles
		5.00x10^-2 moles
		None of the previous answers.

3	How many atoms are in 5.00x10^-2 moles of krypton?
		3.01x10²² atoms
		8.30x10^-26 atoms
		1.20x10²⁵ atoms
		2.52x10²⁴ atoms
		None of the previous answers.

4	What is the mass of 1.80x10²⁴ atoms of krypton?
		3.57x10^-2 g
		2.80x10¹ g
		2.50x10² g
		9.08x10⁴⁹ g
		None of the previous answers.

5	How many atoms are in 8.38 g of krypton?
		4.23x10²⁶ atoms
		6.02x10²³ atoms
		1.66x10^-25 atoms
		6.02x10²⁴ atoms
		None of the previous answers.

6	What is the mass of 1 atom of krypton?
		5.046x10²⁵ g
		1.98x10^-26 g
		1x10^-22 g
		1.392x10^-22 g
		None of the previous answers.

7	What is the formula mass of molecular chlorine in g/mol to four significant figures?
		70.91 g/mol
		35.45 g/mol
		17 g/mol
		38.00 g/mol
		None of the previous answers.

8	Calculate the number of moles in 496 g of chlorine.
		7.00 moles
		14.0 moles
		3.52x10⁴ moles
		0.143 moles
		None of the previous answers.

9	1.2x10²⁰ molecules of chlorine is how many moles of chlorine?
		5.0x10^-4 moles
		2.0x10^-4 moles
		7.2x10⁴³ moles
		4.0x10^-4 moles
		None of the previous answers.

10	What is the formula mass of carbon dioxide in g/mol to four significant figures?
		22.00 g/mol
		76.01 g/mol
		44.01 g/mol
		28.01 g/mol
		None of the previous answers.

11	What is the mass of 2.5x10^-3 moles of carbon dioxide?
		5.68x10^-5 g
		1.76x10⁴ g
		9.09 g
		0.110 g
		None of the previous answers.

12	What is the mass of 1 molecule of carbon dioxide?
		7.31x10^-23 g
		3.77x10^-26 g
		2.65x10²⁵ g
		1.37x10²² g
		None of the previous answers.

13	What is the formula mass of copper(II) nitrate in g/mol to five significant figures?
		241.60 g/mol
		125.56 g/mol
		187.56 g/mol
		None of the previous answers.


14	Calculate the number of moles in 2.00 g of copper(II) nitrate.
		3.75x10² moles
		1.07x10^-2 moles
		9.38x10¹ moles
		2.67x10^-3 moles
		None of the previous answers.

15	What is the formula mass of copper(II) nitrate trihydrate in g/mol to five significant figures?
		241.60 g/mol
		205.57 g/mol
		187.56 g/mol
		None of the previous answers.


16	Calculate the number of moles in 2.00 g of copper(II) nitrate trihydrate.
		8.28x10^-3 moles
		1.07x10^-2 moles
		4.83x10² moles
		2.07x10^-3 moles
		None of the previous answers.

17	What is the formula mass of ammonia in g/mol to four significant figures?
		16.02 g/mol
		15.01 g/mol
		17.03 g/mol
		None of the previous answers.


18	What is the mass of 5.00x10²¹ molecules of ammonia?
		4.88x10^-4 g
		5.13x10⁴⁶ g
		1.77x10⁴⁴ g
		1.41x10^-1 g
		None of the previous answers.

19	How many molecules are in 6.8 g of ammonia?
		6.97x10²⁵ molecules
		6.63x10^-25 molecules
		2.40x10²³ molecules
		5.20x10²¹ molecules
		None of the previous answers.

20	What is the formula mass of molecular nitrogen in g/mol to four significant figures?
		14.01 g/mol
		28.01 g/mol
		14.00 g/mol
		None of the previous answers.


21	What is the mass of 0.0100 moles of nitrogen?
		0.140 g
		3.57x10^-4 g
		0.280 g
		None of the previous answers.


22	0.0100 moles of nitrogen contains ____ molecules.
		6.02x10²³ molecules
		1.66x10^-26 molecules
		6.02x10²⁵ molecules
		6.02x10^-22 molecules
		None of the previous answers.

23	What is the formula mass of potassium sulfide in g/mol to four significant figures?
		71.16 g/mol
		110.3 g/mol
		103.2 g/mol
		None of the previous answers.


24	Calculate the number of moles in 5.00 g of potassium sulfide.
		5.51x10² moles
		1.81x10^-3 moles
		2.20x10¹ moles
		4.53x10^-2 moles
		None of the previous answers.

25	What is the formula mass of ammonium sulfate in g/mol to four significant figures?
		114.10 g/mol
		132.14 g/mol
		210.16 g/mol
		None of the previous answers.


26	How many moles are in 0.250 g of ammonium sulfate?
		3.30x10¹ moles
		1.89x10^-3 moles
		3.03x10^-2 moles
		5.29x10² moles
		None of the previous answers.

27	What is the formula mass of glucose (C₆H₁₂O₆) in g/mol to four significant figures?
		180.2 g/mol
		96.00 g/mol
		340.2 g/mol
		None of the previous answers.


28	How many molecules are in 0.900 grams of glucose?
		9.77x10²⁵ molecules
		8.29x10^-27 molecules
		3.01x10²¹ molecules
		2.69x10^-23 molecules
		None of the previous answers.

29	Calculate the number of moles in 0.476 g of bromine.
		2.98x10^-3 moles
		3.36x10² moles
		5.96x10^-3 moles
		76.1 moles
		None of the previous answers.

30	It is determined that 6.90x10^-3 moles of an element have a mass of 0.662 g. The element is probably:
		Zr
		Pd
		Mo
		Ti
		None of the previous answers.

31	By titration, it is found that 3.05 g of an organic acid contains 2.50x10^-2 moles. What is the molecular mass of the acid?
		122 g/mol
		8.20x10^-3 g/mol
		0.0762 g/mol
		None of the previous answers.


32	Assuming that the limit of the most sensitive balance that can be built is 1x10^-6 g, what is the smallest number of atoms of neon that could be detected by a balance?
		1x10¹⁹ atoms
		3x10¹⁶ atoms
		8x10^-32 atoms
		3x10^-29 atoms
		None of the previous answers.

33	The mass of the earth is about 6x10²⁷ g. Assuming that it is made of iron (about 1/3), how many atoms are in the earth?
		2x10² atoms
		2x10⁵³ atoms
		6x10⁴⁹ atoms
		6x10⁵ atoms
		None of the previous answers.