Formative assessment KEY
1. How many sig figs are in:
b. 0.00300sec __3__ c. 5030J _3___ d. 0.0084 ml __2___ e. 3.450x108 m ___4_
a. 4.0028g _5___
2. Convert 4.58x 107 nm/hr to dm/ms
4.58 x107 nm
1hr
1 dm
1 hr
1s
108 nm
3600s
1000 ms
= 1.27x 10 -7 dm/ms
3. If the volume of an object is 2.8 x10 -2 dm 3 and the mass is 5.08 g, determine density in g/cm3.
2.8 x 10-2 dm3
103 cm3
= 28 cm3
D= m/V= 5.08g/28 cm3 = .18g/cm3
1 dm 3
4. The Olympic record for the mens .400 km dash is 43.98seconds. Convert this speed to miles per hour.
(1 km= .621 mile
1 ft= 12 in
1 in= 2.54 cm)
.400 km
60 sec
60 min .621 mile = 20.3 miles/hr
43.98sec
1 min
1 hr
1 km
5. Round the following values to 3 sig figs and express the answer in scientific notation.
a. 2845972903 ml ____2.85x 109 ml_______________
b. 0.003847530 kg ____3.85x 10-3 kg_______________
6. Solve the following problems and report the answer in the correct number of sig figs.
a. 23.0 g + 20.38 g + 48.049 g = 91.4 g
b. (65.4) x (0.0033)/ (150) = 1.4 x 10 -3 or .0014
7. A student does an experiment to find the specific heat capacity of water. He repeats the experiment
three times, and comes up with values of 3.58 J/g°C, 3.56 J/gºC and 3.55 J/g°C. The actual specific heat
capacity is 4.18 J/gºC. Calculate his % error.
Average= 3.58+ 3.56+ 3.55 = 3.56 J/g⁰C
3
% error = I a-e I x 100 = I 4.18- 3.56I x100= 15%
a
4.18
8. Find the wavelength of a photon having 2.634 x 1014 J of energy.
E= hc/E= 7.547 x10 -40 m
9. Complete the table:
Isotope
Neon - 20
Neon- 21
Neon- 22
Mass (amu)
19.992
20.994
X = 22.007 amu
Abundance (%)
90.51
.27
9.22
Total%: 100
10. Write the complete reaction for each nuclear process below:
a.
210
87𝐹𝑟
b.
42
18𝐴𝑟


(alpha decay )
4
2∝
+
(beta decay with gamma radiation)
206
85𝐴𝑡
0
−1𝛽
+
42
19𝐾
+ 00𝛾
11. Determine the half-life of an isotope if a 840g sample of the isotope decays to 52.5g in 625
days.
840g 420g 210g  105g  52.5g
625 deys / 4 half –lifes= 156 days