I GCHEM SIG/FIG CONCEPT PROBLEMS
Before performing the calculations of a problem, determine the number of sig/figs in all
given data, imported data, and constants. Based on this determination, estimate the
number of sig/figs that will be in your final answer (least precise data or constant). While
performing the calculation always carry one digit more than the number of sig/figs that
will be in your final answer to accommodate rounding. Round final answer ONLY !!!
Underline a number in the problem that will determine number of sig/figs in final answer.
1.
A brass cylinder is 4.668 inches long. If 1.00 inch equals 2.5 centimeters, how long is the brass
cylinder in centimeters ?
extra digit for rounding
Gross Answer = 11.6
2.
S/Fs
Answer: _____________________
S/Fs
Answer: ______________________
S/Fs
Answer: ______________________
The standard density of copper is 8.92g/cm3. Based on the following density determinations for
copper : 1) 8.32, 2) 9.21, 3) 8.523, and 4) 8.86 g/cm3, what is the percent error compared to std ?
percent error = (calculated avg density minus std density)/std density *100
Gross Answer = ____________
7.
Answer: is ______________________
What the density (density = mass/volume) of an irregular aluminum object that has a mass of 12.5
grams and volume* determined by difference in water displacement of 98.3 cm3 minus 64.564 cm3.
Gross Answer = ____________
6.
S/Fs
What is the calorimeter temperature change (T = Tf - Ti ) during an exothermic chemical reaction
if the T (initial) is 24.54 o C and the T (final) is 35.4 o C.
Gross Answer = _____________
5.
Answer: __________12__________
What is the mass of a NaCl sample in a beaker if the mass of the beaker is 35.724 grams and mass
of beaker and NaCl is 45.67 grams ?
Gross Answer = _____________
4.
2
Average the following mass values of a copper wire: 12 grams; 12.2 grams;14.23 grams
Gross Answer = ____________
3.
S/Fs
S/Fs
% Error: ______________________
The heat of reaction for AlCl3 (s) was measured in a calorimeter (kJ/mole) three times as follows:
#1) 701.2, #2) 685.24, and #3) 712.234 kJ/mole. What is the percent error compared to
standard textbook value ( - 705.6kJ/mole) ?
Gross Answer = ____________
S/Fs
% Error: ______________________
jpechunf02/2007