Reading Instruments:
Significant Figures:
1.
Determine the number of significant figures in each of the following:
a. _____ 75.02mm
f. ________ 150. Cm
b. _________ 0.0049 g
g. _________ 0.00456 mg
c. _______ 18.90 mL
h. _________ 107.20 mm
d. _______ 150 cm
i.
_________ 1720 g
e. __ ___ 12 test tubes
j.
_________ 3.03 x 10-1 kg
2. Rewrite the quantity 0.0031904 kg to show:
a. 1 sig. fig.
b. 2 sig. figs.
c. 3 sig. figs.
3. Round each of the following to 3 significant figures:
a. 0.14986 L
b. 861.85 kg
c. 4.203 x 104 km
d. 5.0981 x 10-3g
4.
Determine the uncertainty in each of the following:
a. 75.02mm
b. 18.90 mL
c. 150 cm
d. 150. cm
e. 0.00456 mg
f. 107.20 mm
5. Complete the mathematical operations and round to the proper number of significant
figures:
a. 31.06 m – 26.42 m
b. 5.058 g + 13.1 g
c. 15.2 L + 273.15 L
d. 87.54 cm – 83.2 cm
e. 76 s – 15.62 s
f. 1100 m + 110.5 m + 10.05 m
6. Complete the mathematical operations and round to the proper number of significant
figures:
a. 176.3 m / 2.8 s
b. (0.00340 x 57.21)/(2.99 x 1.6)
c. 3.4 x 10-5/2.66
d. (65,000.0 x 2.311)/2.91
Accuracy vs. Precision and Percent Error:
1.
For each of the following, label the accuracy and precision as either high or low.
accuracy ________
accuracy ___________
accuracy ________
precision _________
precision ___________
precision _________
2. A measurement was taken three times. The correct measurement was 68.1 mL. Circle whether
the set of measurements is accurate, precise, both, or neither.
a. 78.1 mL, 43.9 mL, 2.0 mL
accurate
precise
both
neither
b. 68.1 mL, 68.2 mL, 68.0 mL
accurate
precise
both
neither
c. 98.0 mL, 98.2 mL, 97.9 mL
accurate
precise
both
neither
3.
A 250.0 gram block is placed on a balance. The balance measures the mass of the block as 243.9 grams.
What is the percent error of the block?
4.
A teacher calculates the molar mass of sodium hydroxide as 37 g/mol. The true molar mass of sodium
hydroxide is 40 g/mol. Find the teacher’s percent error.
Scientific Notations:
1. Transform the following notations into proper scientific notations:
a.
672.10 mm = ________________
e.
0.00876 x 10-4 g = ________________
b.
0.000749 g = ________________
f.
7456 x 105 m = _______________
c.
0.003452 x 10-4 mL = ________________
g.
0.0002189 x 104 L = ______________
d.
230.4 x 106 cm = ________________
h.
356.92 x 10-6 m =________________
2. Fill-in the blanks.
a.
3.25 x 10-4 g = _________ x 10-2 g = ____________ x 10-6 g
b.
7.932 x 103 cm = ___________ x 10-1 cm = ______________ x 105 cm
c.
1.45 x 10-4 L = _____________ x 10-5 L = _______________ x 10-3 L
d.
7.65 x 105 kg = ____________x 103 kg = ______________ x 107 kg
e.
4.762 x 10-5 m = __________ x 10-3 m = ____________ x 10-7 m
3. Complete the mathematical operations and round to the proper number of significant
figures:
a. 2.54 x 10-3 m – 2.64 x 10-4 m = ____________
b. 5.06 x 104 g + 1.31 x 105 g = _______________
c. 1.52 x 10-3 L + 2.73 x 10-4 L = _____________
d. 8.754 x 10-3 cm – 8.32 x 10-4 cm = ____________
4. Complete the mathematical operations and round to the proper number of significant
figures:
a. (3.763 x 102) m / (1.82 x 104)s = ______________
b. (7.40 x 10-5) g/(2.9 x 10-2) cm3= _________________
c. (6.44 x 10-2) cm x (4.663 x 103) cm = ____________________
d. (6.523 x 10-4) m x (2.913 x 103) m = __________________
Dimensional Analysis:
1. Convert the following units.
a. 5.392 x 10-5 m to m (1 m = 10-6 m)
b. 7.76 x 108 mg to g (1 mg = 10-3 g)
c. 9.2 x 102ns to s (1 ns = 10-9 s)
d. 4.91 x 10-12 daL to L (1 daL = 101 L)
2. Convert the following units.
a. 4.29 x 102 cm to pm (1 cm = 10-2 m; 1 pm = 10-12 m)
b. 2.87 x 10-4 Gs to ms (1 Gs = 109 s; 1 ms = 10-3 s)
c. 3.16 x 1012 g to Mg (1 g = 10-6 g; 1 Mg = 106 g)
d. 4.62 x 104 mL to ML (1 mL = 10-3 L; 1 ML = 106 L)
3. Answer the following questions.
a. How many mm are there in 3.56 miles? (1 mile = 1760 yards; 1 yard = 3 ft.; 1 ft. = 12 in.;
1 in. = 2.54 cm; 1 cm = 10-2 m; 1 mm = 10-3 m)
b. How many s are there in 2.5 years? (1 s = 10-6 s; 1 min. = 60 s; 1 hr. = 60 min.; 1
day=24 hr.; 1 yr. = 365 days)
c. Convert 5.98 x104 kg/m3 to g/cm3. (1 kg = 1000 g; 1 m3 = 106 cm3) [Note: very
challenging question. Think hard.]
1. Convert the following units.
a. 6.59 x 10-4 cg to ng
b. 4.82 x 104 mL to GL
c. 5.46 x 10-2 m to Hg
2. Answer the following questions.
a. How many mm are there in 3.56 miles? (1 mile = yards; 1 yard = 3 ft.; 1 ft. = 12 in.; 1 in.
= 2.54 cm; 1 cm = 10-2 m; 1 mm = 10-3 m)
Moles to Number of Particles:
Apply the unit analysis (monkey-bar) approach. Write the details on paper.
1. Convert from number of particles to moles.
a. 1.204 x 1024 He atoms
b. 100 Ar atoms
c. 1 S atom
d. 6.78 x 1020 water molecules
e. 4.92 x 1018 carbon dioxide molecules
2. Convert from number of moles to number of particles.
a. 3.00 moles Li
b. 8.50 x 10-2 moles Ca
c. 0.001 moles Al
d. 1.66 x 10-4 moles of CO
3. Answer the following questions. [More complex problems. Some need to be set up properly.]
a. How many moles of sodium atoms are there in 3.5 moles of sodium carbonate?
b. How many hydrogen atoms are there in 3.45 x 10-3 moles of calcium bicarbonate?
c. How many moles of calcium bicarbonate that would contain 5.82 x 10 24 carbon atoms?
Moles to Mass:
Apply the unit analysis (monkey-bar) approach. Write the details on paper.
1. Determine the number of representative particles in each of the following. Note: pay close attention to
significant figures and scientific notation.
a. How many nitrogen atoms are there in 0.425 mol nitrogen gas molecules (N2)?
b. What is the total number of atoms (hydrogen + oxygen) in 3.4678 x 10-4 mol water molecules
(H2O)?
2. Determine number of moles of representative particles in each of the following. Note: pay close
attention to significant figures and scientific notation.
a. How many moles of oxygen atoms are there in 4.96 x 1024 molecules of Na2SO4?
b. How many moles of NaHCO3 is needed to produce 5.39 x 1025 oxygen atoms?
3. Make the following conversions. Note: pay close attention to scientific notation.
a. 1.51 x 1015 atoms Fe to mol of Fe2O3
b. 4.25 x 10-2 mol of hydrogen atoms in H2SO4 to molecules H2SO4
c. 8.95 x 1025 molecules CCl4 to mol of Cl atoms
4. How many moles of each individual element are present in 1 mole of the compounds below?
a. Na2CO3
b. C5H12
c. N2O5
5. Determine the molar mass of the following compounds.
a. C7H14O2
b. Ca(OH)2
c. Dinitrogen pentoxide
d. Iron(III) sulfite
6. For each of the compound given in Q5, calculate the number of moles of molecules (or formula units)
present in 50.00 grams of sample.
7. For each of the compound given in Q5, calculate the mass that is equivalent to 2.54 mol.
More Complex Moles Problems:
1. Answer the following questions.
a. How many nitrogen molecules (N2) are there in 12.65 grams of nitrogen gas?
b. How many grams are there in 3.4678 x 1024 water molecules (H2O)?
c. How many pentane (C5H12) molecules are there in 46.3 grams of pentane?
d. How many moles of aluminum sulfate are there in 6.29 x 1020 formula units of aluminum
sulfate?
2. Answer the following challenging questions. (optional)
a. How many oxygen atoms are there in 4.96 grams of Na2SO4?