CHM2045
WS01
1.
Briefly explain the relationship between hypothesis and experiment in the scientific method.
Hypothesis and experiment have a symbiotic relationship in the scientific method. A hypothesis is formed and after further testing (a.k.a
experiments), the results will tell us if the hypothesis is correct.
2. The density of water at 298K (room temperature) is 0.9970𝑔/𝑐𝑚3 . What is the density in kg/𝑚3 ?
298𝑘 ×
0.9970
𝑔
𝐶𝑚3
×
1𝑘𝑔
1000𝑔
×
1000000𝐶𝑚3
=
1𝑚3
=
3.
297106
𝑘𝑔
𝑚3
297𝑘𝑔
𝑚3
If an object is traveling at 30.0 meters per second, how fast is it moving in miles per hour?
30.0𝑚
1𝑚ⅈ
60𝑠
60𝑚ⅈ𝑛
×
×
×
= 67.108 = 67.1
̇
𝑠
1609.34𝑚 1𝑚ⅈ 𝑛
1ℎ𝑟
4. An acre is defined as a unit of land that is 1 chain (22 yards) by 1 furlong (220 yards). How many square
meters is an acre?
1𝑎𝑐 ×
4046.86𝑚2
1𝑎𝑐
= 4046.86𝑚2
5. The S.I. unit of energy is the joule, J. 1 J= 1 𝑘𝑔 ∙
2
2
𝑚2
.
𝑠2
Another energy unit, the erg, was once in widespread
use. 1 erg= 1𝑔 ∙ 𝑐𝑚 /𝑠 . Calculate the number of ergs in 1 J, showing all your work.
1𝑘𝑔 ×
1𝑚2 1000𝑔 10000𝐶𝑚2
×
×
× 𝑠 2 = 10000000 = 1.0 × 10−7
𝑠2
𝐼𝑘𝑔
1𝑚2
CHM2045
WS01
6. Classify the following properties of hydrogen gas as either intensive or extensive.
a) The mass of the gas sample
b) The average speed of a molecule in the sample
c) Temperature
d) Density
e) Number of molecules present
7.
An evacuated 276 mL glass bulb ways 129.6375 grams. Filled with an unknown gas, the bulb weighs 130.0318
grams. Calculate the gas density in g/L, and express it with an appropriate number of significant figures.
8. Use the relationship between temperatures in Celsius and Fahrenheit to calculate the temperature at which
a. the numerical value is the same on both skills.
b.
The Fahrenheit number is exactly twice the Celsius number.
CHM2045
WS01
9. Write the following numbers and results in scientific notation, with appropriate significant figures.
a. 654
b.
1234560
c.
0.000000673
d.
0.002590
e.
200.4
f.
260.0
g.
𝜋𝑟 2 , where r= 8.7 𝑐𝑚
h.
23.24 + 18.6 − 5
10. Write the following numbers and results in standard notation, with appropriate significant figures.
a.
7.85× 10−3
b.
7.85× 104
c.
5.920× 103
d.
7.85× 1012 ÷ 1.0 × 1010
e.
f.
7.00× 10−5
Circumference of a circle, 2𝜋𝑟, where r= 8.7 𝑐𝑚
g.
6.626×10−34 ×6.02214×1023 ×2.9979×108
5.23×10−6