•HChemistry Name
1•ChemistryFoundations Period Date
1 .1 PROB L EMS - M EA SU R EM ENTS
1. Writethefollowingnumbers in scientific notation.
Circlethe significantdigits. a. 0.000250
b. 2,000
c. 0.02081 d. 900.
2. Writethefollowingnumbers in standard decimal notation. Circle the significantdigits.
a. 2.150 × 102
b. 8.8 × 10–4 c. 1.00 ×10–5 d. 4.337 ×106
4. Howshouldeach measurementbe recorded?
Themass ofsamplesofsolid sodiumbicarbonate wasmeasuredin grams usingan electronic balance.
(a) 204.8 (b) 18.40 (c) 0.73
(d) 2.00
Thelength ofa strip ofmagnesiumwasmeasured in cmusinga ruler.
(e)
(0.1285)(38.00)
a. (0.08206)(255.)
(g)
1 2 3 4
5 cm
1
1
1000.
(h)
1 2 3 4
5 cm
b. 2.56 ×110.99×0.25× 1
c. 5.6792 +0.6 + 4.33
The volume ofsolutionsof copper(II)chloride was measured in mL using graduatedcylinders.
(i) (j)
400 20
d. 3.70 – 2.9133
300 10
e. (1.74 ×1024) 1 22.4
6.0223 ×1023 1
2460
f. (0.0385)(100.0 –28.6)
The volume ofa solutionofpotassiumhydroxide wasmeasuredin mL usinga buret.
(k) (l)
14 6
15 7
g. (3.26 ×10−3) –(7.88 × 10−5)
h. (4.02 ×106) +(7.74 ×107)
Thetemperature ofwaterina beakerwas measured in Celsius(ºC)usinga thermometer.
(m.) (n)
(a) For each group,(i)reportthe measurement usingtheaverage valueandaverage deviation, and (ii)findthe percenterror.
30 30
20 20
5. Two groupsofstudents determined the densityof an aluminumbar. Group Ausesa simple metric ruler, whileGroup Busesaprecision micrometer. Thecalculated densitiesareshown below.The accepted valueforthe densityofaluminumis 2.702
g/cm3.(Usecomplete sentencesin yourresponses.)
(b)Group A’sresultsreportedwithtwo significant figures, while Group B’sresults arereported withfoursignificantfigures. Whatisthe reason forthe difference?
Group A(g/cm3)
2.5
2.7
2.7
2.6
Average: Deviation:
Group B(g/cm3)
2.793
2.801
2.805
2.784
Average: Deviation:
(c) Howdoesthe measuringinstrumentaffect the precision ofa setofmeasurements?
(d)Which Groupis moreaccurate?Which group is more precise?Howdo you know?