Calculations WS

Molar Conversion/Percent Composition
Calculate the number of moles in the following.

1)0.039g of carbon 0.0032

2)8200g of zinc 130

Calculate the mass in grams of each of the following amounts.

3)1.002mol of chlorine 35.52

4)550mol of manganese 3.0x104

Calculate the number of atoms in each of the following amounts.

5)17.0mol of xenon 1.02x1025

6)0.6144mol of aluminum 3.700x1023

Calculate the number of moles in each of the following quantities.

7)6.022 x 1024 atoms of germanium10.00

8)1.06 x 1023 atoms of radon 0.176

Calculate the number of atoms in each of the following masses.

9)0.0082g of uranium 2.1x1019

10)812g of cobalt 8.30x1024

Calculate the mass of each of the following.

11)8.22 x 1023 atoms of cesium 181

12)9.96 x 1026 atoms of iodine 2.10x105

For each of the following, (a) find the molar mass, (b) complete the conversion, and (c) find the % composition.

13)46.3g CsI = ___mol CsI 259.81, 0.178, 51.16%, 48.84%

14)1.03mol C2H3O2 =___g C2H3O2 59.05, 60.8, 40.68%, 5.13%, 54.19%

15)3.19 x 1024formula units (NH4)2HPO4 =____g (NH4)2HPO4132.08, 700., 21.21%, 6.88%, 23.45%, 48.46%

16)0.32mol NaHCO3=____formula units NaHCO384.01, 1.9 x 1023, 27.37%, 1.20%, 14.30%, 57.14%

17)2.04 x 1024 formula units Fe(OH)3=____mol Fe(OH)3 106.88, 3.39, 52.25%, 44.91%, 2.83%

18)3.97mol Mg3(PO4)2 =_____g Mg3(PO4)2 262.87, 1040, 27.74%, 23.56%, 48.69%

19)207.15g Ba(OH)2•8H2O=_____ formula unitsBa(OH)2•8H2O 315.51, 3.954 x 1023, 43.53%, 10.14%, 0.64%, 45.69%

20)185.3g Pb(CH3COO)2•3H2O =______mol Pb(CH3COO)2•3H2O 379.36, 0.4885, 54.62%, 12.66%, 16.87%, 1.60%, 14.25%

21)4.02 x 1023 molecules C6H12O6 =____g C6H12O6 180.18, 120, 39.99%, 6.73%, 53.28%

22)2.81mol CoCl2∙6H2O=_____ formula unitsCoCl2∙6H2O 237.95, 1.69x1024, 24.77%, 29.80%, 45.44%

23)3.61 x 1023form unitsmagnesium sulfate heptahydrate=__molmagnesium sulfate heptahydrate246.52, 0.599, 9.86%, 13.01%, 25.96%, 51.17%

24)17.59g chromium II phosphate= ____mol chromium II phosphate345.94, 0.05085, 45.09%, 17.90%, 37.00%

25)5.09g tetraphosphorous decoxide=___ molecules tetraphosphorous decoxide 283.88, 1.08x1022, 43.64%, 56.36%

Empirical/Molecular Formula

Determine the empirical formula for compounds that have the following analyses:

26)80.38% bismuth, 18.46% oxygen, 1.16% hydrogen BiO3H3

27)12.67% aluminum, 19.73% nitrogen, and 67.60% oxygen AlN3O9

28)35.64% zinc, 26.18% carbon, 34.88% oxygen, and 3.30% hydrogen ZnC4H6O4

29)76.89% Re and 23.12% O Re2O7

30)5.04% H, 35.00% N, and 59.96% O N2H4O3

Determine the empirical formula for compounds that have the following analyses:

31)a 13.07g sample of an unknown substance is composed of 9.48g of barium.1.66g of carbon, and 1.93g of nitrogen. BaC2N2

32)A 0.025g sample of an unknown substance is composed of 0.0091g manganese, 0.0106g oxygen, and 0.0053g sulfur. MnSO4

33)A sample was found to contain 1.116 g of iron and 0.480 g of oxygen. Fe2O3

34)A 0.470g sample contains 0.144g of manganese, 0.074g nitrogen, and 0.252g of oxygen. MnN2O6

35)A 3.880g sample contains 0.691g of magnesium, 1.824g of sulfur, and 1.365g of oxygen. MgS2O3

Determine the molecular formulas for compounds having the following empirical formulas and molar masses:

36)C2H3O2; experimental molar mass 119 C4H6O4

37)C2H2O; experimental molar mass 254 C12H12O6

38)NH2; experimental molar mass 32.06 N2H4

Use the experimental molar mass to determine the molecular formulas for compounds having the following analyses:

39)54.53% Carbon, 9.15% hydrogen, and 36.32% oxygen; experimental molar mass 88 C4H8O2

40)64.27% carbon, 7.19% hydrogen, and 28.54% oxygen; experimental molar mass 168.19 C9H12O3

41)A 2.65g sample of a salmon-colored powder contains 0.70g of chromium, 0.65g of sulfur, and 1.30g of oxygen. The molar mass is 392.2. What is the formula of the compound? Cr2S3O12

42)Histamine is a substance that is released by cells in response to injury, infection, stings, and materials that cause allergic reactions, such as pollen. Histamine causes dilation of blood vessels and swelling due to accumulation of fluid in the tissues. People sometimes take antihistamine drugs to counteract the effects of histamine. A sample of histamine having a mass of 385mg is composed of 208mg carbon, 31mg of hydrogen and 146mg of nitrogen. The molar mass of histamine is 222g/mol. What is the molecular formula for histamine? C10H18N6

43)A compound composed of hydrogen and oxygen is found to contain 0.59 g of hydrogen and 9.40 g of oxygen. The molar mass of this compound is 34.0 g/mol. H2O2

44)An unknown compound was found to have a percent composition as follows: 47.0 % potassium, 14.5 % carbon, and 38.5 % oxygen. If the true molar mass of the compound is 166.22 g/mol, what is its molecular formula? K2C2O4

45)The percentage composition of acetic acid is found to be 39.9% C, 6.7% H, and 53.4% O. Determine the empirical formula of acetic acid. The molar mass was determined by experiment to be 60.0 g/mol. What is the molecular formula? C2H4O2